DERR-2024-012963

Chevron Environmental Management Company

Tier 2 Risk Assessment
Chevron Service Station No. 211535
19 North Main Street
Teasdale, Utah 84773
DEQ Facility ID #2000143
Release Site GOC

June 5, 2024, revised November 21, 2024

Tier 2 Risk Assessment
This document is intended only for the use of the individual or entity for which it was prepared and may contain information
that is privileged, confidential and exempt from disclosure under applicable law. Any dissemination, distribution or copying of
this document is strictly prohibited.
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211535 Tier 2 Risk Assessment 21NOV2024 i
Tier 2 Risk Assessment
Chevron Service Station No. 211535
19 North Main Street
Teasdale, Utah 84773
DEQ Facility ID #2000143
Release Site GOC

June 5, 2024, revised November 21, 2024

Prepared By: Prepared For:
Arcadis U.S., Inc. Ms. Eileen Brennan
630 Plaza Drive, Suite 200 Utah Department of Environmental Quality
Highlands Ranch Division of Environmental Response and
Colorado 80129 Remediation
Phone: [phone] North 1950 West
Fax: [phone] Salt Lake City, Utah 84116

Our Ref:
30062776

________________________________________
Erin Osborn
Risk Assessor

________________________________________ ________________________________________
Siobhan Pritchard Taura Nichols, P.E.
Project Manager Utah PE license #8568538-2202
Certified Consultant No. CC-0247

Tier 2 Risk Assessment
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211535 Tier 2 Risk Assessment 21NOV2024 ii
Contents
Executive Summary
Appendix B
1.1 Worksheet #1 Risk Assessment Report
1.2 Worksheet #2 Data Requirements
1.3 Worksheet #3 Site Conceptual Exposure Model
1.4 Worksheet #4a Plume Stability Results
1.5 Worksheet #4b Mass Calculations for Initial and Ending Dissolved Phases
1.6 Worksheet #4c Mass Calculations for Initial and Ending Adsorbed Phases
1.7 Worksheet #4d Determining Percent Decrease in Dissolved COC Concentrations in Contaminant
Plumes
1.8 Worksheet #4e Statistical Evaluation of Plume Stability
Appendix C
2.1 Tables
2.1.1 Table B-1 Site-Specific Cleanup Levels for Surface Soil
2.1.2 Table B-2 Site-Specific Cleanup Levels for Subsurface Soil
2.1.3 Table B-3 Site-Specific Cleanup Levels for Groundwater
2.1.4 Table C-2 Soil Analytical Results
2.1.5 Table C-3a Historical Groundwater Monitoring and Analytical Data
2.1.6 Table C-3b Current Groundwater Monitoring and Analytical Data
2.2 Figures
2.2.1 Figure C-1 Site Plan
2.2.2 Figure C-3 Groundwater Elevation Contour Map
2.2.3 Figure C-4 Groundwater Analytical Map
2.3 Attachments
2.3.1 Attachment A Site Vicinity Map (Former soil boring locations) (Secor 2006)
2.3.2 Attachment B Vapor Points Analytical Results (Secor 2006)
2.3.3 Attachment C Site Location Map (Stantec 2010)
2.3.5 Attachment D Additional Site Assessment Report (Secor 2006)
Appendix D
3.1 Appendix D-1 Calculations for Site-Specific Cleanup Levels (SSCLs) – Residential
3.2 Appendix D-2 Calculations for Site-Specific Cleanup Levels (SSCLs) – Construction
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211535 Tier 2 Risk Assessment 21NOV2024 1

Executive Summary
Facility History and Site Characterization
The site was operated for retail gasoline sales from the 1920s until approximately 1987 and contained two 1,000-
gallon USTs and a single dispenser island, and two 550-gallon USTs at an unknown location. The building and
associated property are currently used as a part-time art studio.
Land use at the site and surrounding areas is residential. Buried utilities, including water and telephone, cross
within the area of soil impact under Main Street. Sensitive ecological habitat or surface water are not present in
the vicinity of the site. Drinking water is supplied by a municipal water source and the nearest downgradient
groundwater well not classified as “non-production” is more than 2500 feet from the Site.
The site soil consists of fine-grained sand and silty sand with traces of gravel to a depth of 30 to 35 feet below
ground surface (bgs). Groundwater flows toward the northeast with a hydraulic gradient of 0.256 feet per foot. The
depth to groundwater in the source area fluctuated between approximately 24 and 130 bgs between 1994 and
2023.
Site assessments to evaluate subsurface conditions were conducted in 1994, 1998 and 2005 (Secor, 2000). A
vapor intrusion assessment was completed in 2005. Annual groundwater sampling is ongoing.
Remedial Activities
During UST removal and subsequent subsurface investigation activities, petroleum hydrocarbon impacted soil
and groundwater and light non-aqueous phase liquid (LNAPL) were identified. A two phase (combined
groundwater and soil vapor) extraction and treatment (TPET) system was installed on-site and operated almost
continuously from March 2000 to June 25, 2004, and from February 2, 2005, to July 12, 2005. Operation of the
system was discontinued in July 2005 due to diminished hydrocarbon mass removal. An estimated 16,453
pounds of petroleum hydrocarbons were removed from the subsurface by the TPET system (Stantec, 2017).
Post-remedial Conditions
Residual petroleum hydrocarbons are present in groundwater and subsurface soil beneath the Site. As of the
most recent sampling event (November 30, 2023), constituents exceeding UDEQ ISLs included TPH-GRO and
benzene at off-site monitoring well CGW-12 and benzene at on-site monitoring well AGW-1. Measurable separate
phase hydrocarbons (0.01 foot) were last detected in September 2015 in CGW-12. Post-remedial vadose zone
soil sample analysis fromFSB-6 and FSB-7, collected adjacent to AGW-1 and AGW-2 in November 2005, indicate
soil concentrations within the source area were detected below UDEQ ISLs for soil. No petroleum hydrocarbons
have been detected in soil above ISLs on offsite properties other than beneath Main Street.
The groundwater plume is decreasing based on linear regression analysis of benzene and TPH-GRO
concentrations in groundwater, with concentrations below ISLs expected in all wells by 2039. Additionally, results
of the plume stability evaluation indicate that the dissolved phase hydrocarbon plumes are stable to diminishing
(Worksheets #4a through #4e). Adsorbed phase mass calculations are not available, as post-remedial soil
samples are limited to one sampling event conducted in 2005. Prior to remediation, offsite soil concentrations of
petroleum-related compounds were below ISLs and/or Tier I Screening Criteria, except for the onsite source area
and some locations adjacent to the Site boundary and within the Main Street right of way.
Currently, monitored natural attenuation (MNA) is the selected corrective action methodology for the site. MNA
was approved as the remedial technology for the site in an April 25, 2016, Corrective Action Plan Addendum
Approval Letter. However, as the primary source has been removed/treated and limited impacts remaining in
Tier 2 Risk Assessment
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211535 Tier 2 Risk Assessment 21NOV2024 2
groundwater continue to attenuate, a risk assessment was performed to support a no further action determination
and remove the site from continued monitoring.
Tier 2 Risk Assessment
The Tier 2 Risk Assessment evaluated potential exposures associated with residual petroleum hydrocarbons
present in surface and subsurface soil, groundwater, and indoor and outdoor air. Potential receptors included
onsite and offsite residents, site visitors, and future construction workers. As described below, the exposure
pathways were evaluated quantitatively and determined to be currently incomplete.
Groundwater ingestion is currently an incomplete exposure pathway as drinking water is supplied by a municipal
water source. Although residual benzene concentrations in groundwater exceed Option 1 SSCLs for drinking
water and UDEQ ISLs, onsite and offsite properties are supplied with municipal drinking water. Therefore, the
drinking water exposure pathway is incomplete. Residual petroleum hydrocarbon concentrations in all onsite and
offsite groundwater wells are projected to be below ISLs by 2039.
Direct contact with soil exposure pathways are incomplete as residual petroleum hydrocarbon concentrations do
not exceed Option 1 SSCLs and/or ISLs. For surface and shallow soil in the 0 to 10 ft bgs interval, residual
petroleum concentrations are below ISLs. Post-remedial soil data are not available below 10 ft bgs, however, pre-
remedial petroleum hydrocarbon concentrations at 15 ft bgs are below Option 1 SSCLs for direct contact
exposure pathways.
For potential inhalation of vapors in air that originate from residual petroleum hydrocarbons in subsurface soil
and/or groundwater, soil vapor data indicate that vapor intrusion is not occurring. Benzene was the only petroleum
constituent detected in soil vapor collected at 4.5 ft bgs above the indoor air SSCL. Using the USEPA (2015)
default soil vapor-to-indoor air attenuation factor (AF) of 0.03, predicted indoor air concentrations are below the
Option 1 indoor air SSCL. The default AF was derived for chlorinated solvents and overestimates indoor air
concentrations for petroleum hydrocarbons that are subject to significant biological degradation in soil.
Additionally, outdoor air concentrations would be lower than predicted for indoor air due to dilution with ambient
air. Significant biological degradation is likely since soil vapor data were collected in 2005.
Utility lines were not considered a complete exposure pathway, based on the depth to historical hydrocarbon
concentrations in soil (typically 30 feet bgs or deeper). Post-remedial vadose soil samples collected from borings
FSB-6 and FSB-7 to 10 ft bgs did not contain petroleum hydrocarbons concentrations above ISLs and further
indicate utilities are not impacted by soil contamination. However, if construction work will be conducted on utility
lines in Main Street it is advised that DERR and/or 811 Blue Stakes be notified to ensure any potentially
contaminated soil encountered is handled appropriately.
Conclusions and Recommendations
No additional remedial work is recommended. Evaluated potential exposure pathways are currently incomplete
and multiple lines of evidence indicate ongoing natural attenuation of residual petroleum hydrocarbons in the
subsurface. Additionally, potentially remaining residual hydrocarbons present under Main Street can be managed
as part of the Blue Stakes program. An environmental covenant can be used to mitigate residual hydrocarbons
detected within the groundwater and potential vapor intrusion.
Based on the information presented in this Tier 2 Risk Assessment, Arcadis, on behalf of Chevron Environmental
Management Company, respectfully requests a No Further Action determination by the DEQ.
Appendix B
Worksheets

 
  
            
         
             
      
      
         

    
        
        
    
          
    
       Print and sign your name in this portion to acknowledge that you are providing
accurate information used for formulating your conclusions regarding any remaining contamination, exposure pathways and receptors.
If exposure pathways are complete, receptors are likely to be at risk, and further action may therefore be necessary.
               
       
         
  Summarize each of the following:            
                 
    
                    
                      
                     
                    
                    
                 
                
                 
                   
                     
                
   
                   
               
                
                 
              
                
                    
       
                
                   
        
                
           
 
  

    Describe site characteristics and assessment results including the following:
                  
                      
    
                      
                      
                  
                    
               
                 
                  
                      
               
     
                         
                     
                       
                   
            
                 
                    
                
                
              
                 
        
               
                
               
                
                  
              
                 
                 
                 
            
                  
                 
                   
                 
               
                   
                  
                         
                     
                
                   
                    
                    
        
                
           
 
  

      
                      
                
 
            
        Mark the applicable spaces provided below,, for the
option used to calculate and/or derive SSCLs, and describe why the Option was used.
   
                
                  
           
       
                 
       
                

   
         
      
 
               
       
                 
       
                

   
         
       
  
         
                 
       
                

   
         
       
  
         
                  
      
                 
        
                
           
 
  

  
                    
                
            

1. Check the boxes below where applicable.
2. Discuss each current and potentially complete exposure pathway, on-site and off-site receptors, and land use and exposed
populations in the space provided. Exposure pathways are complete in accordance with Worksheet #3 (Site Conceptual Exposure
Model), and when all the following conditions exist: (a) Receptors are present; (b) Transport mechanisms are active, and; (c) The
SSCLs or ALs are exceeded. A potentially complete exposure pathway is one that is likely to be complete in the future, generally
within 5 to 10 years.
3. If pathways are potentially complete, discuss the likelihood of receptors being exposed to contaminant concentrations greater than
the TER (i.e., a 10
-6 TER for carcinogenic compounds, 1.0 Hazard Quotient for non-carcinogenic compounds, ISLs or other
standards).
  
        
[NOTE: The Surface Soil pathway must be considered if subsurface soil will potentially be excavated.]
                       
 
                  
                          
       
                  
                      
                  
   
                     
                        
                
                      
                    
                    
                       
                      
                  
     
                  
                        
                     
    
  continued
        
NOTE: Subsurface soil has the potential to become surface soil if it is excavated.
                       
 
                  
                     
                
        
                
           
 
  

                
                     
                       
                    
                    
                       
                        
                    
               
                  
     
                 
                   
                       
                  
                      
              
     
             
  
         
         
                  
                  
          
         
       
            
                  
                    
                  
  continued
        
                       
 
                  
                       
         
                   
                   
                         
                      
                        
               
                       
                
                   
     
                
                 
                   Assumes Chevron
Waste T&D subcontractor can provide adequate trucks for disposal.         
                   
                    
                       
                       
                      
                  
                   
               
        
                
           
 
  

                 
                   
                      
                  
                      
               
                 
  
             
      
  
                    
                
                   
                 
  
                 
                   
                    
               
  continued
       
                       
  
                 
                   
        
                
                
                 
                  
                
                   
                
                
              
                 
                   
                      
                  
                      
               
                 
  
                  
                   
                  
            
       
         
         
                  
                 
  continued
       
                       
 
                 
                   
        
        
                
           
 
  

                
                
                 
                  
           
                    
                 
             
                    

                 
                   
                      
                  
                      
               
                 
  
                  
                   
                  
            
       
         
       
                     
                    
                     
            
  
       
                       
 
                 
                 
                      
                  
            
                   
                   
                        
                  
                   
                  
                    
                   
                  
                    
                 
             
                
                
                   
               
        
                
           
 
  

  continued
   
                       
 
               
                   
                    
                 
     
                 
                
                  
                      
                     
                 
                     
              
             
                    
                   
              
  [NOTE: This pathway must be considered if subsurface soil will potentially be excavated.]
          
       
                       
 
                 
                          
                  
                 
        
                  
                      
              
                      
                        
                
                       
                   
                     
                       
                     
                  
               
                  
                 
                   
                     
  continued
        
                
           
 
  

   
              
      
                
                 
                    
                     
                 
                  

                      
            
        
                
           
 
  

       Contaminants must attenuate to the Target Excess Risk
level (10
-6 and Hazard Quotient = 1.0), ISLs or other applicable standards at all receptors.
      

                  
                      
                   
                
                     
  
                    
               
                 
                    
                  
        

                    
                   
           
     (check the applicable below and specify analytical or numerical)
     
       
            

     

                  
               
                 
                    
                      
      

                   


                    
          

           

        
                
           
 
  

  
                    
          
NOTE: DO NOT PROCEED WITH PUBLIC NOTIFICATION UNTIL THE FORM SHOWN BELOW HAS BEEN COMPLETED,
AND REVIEWED AND APPROVED BY THE EXECUTIVE SECRETARY.
                 
            
       
         
           
                    
                      
                     
                 
              
                  
                  
                        
               
     
                   
                
                
                 
                  
                   
                   
                
          
       
                
                  
               
                 
                
                
                   
                  
                   
                      
                 
                   
                  
                     
                  
                    
               
                   
       
        
                
           
 
  

           
                  

                
          
       
            
        
                
           
 
  

              
                  
               
                 
                    
                      
                     
                    
             
                 
                
                  
                     
                     
                 
                   
               
                
                 
                  
                   
                    
                
         
                  
              
                      
                   
      
                  
                
                 
                    
                    
                 
                      
                
          
                 
          
        
                
           
 
  

               
                     
                        
       
                  
           
                
               
                 
  
        
                
               
             
          

      
     
         
        
      
  
       

  
 
  
     
   

 
 

               
             
              
        
               
               
             
                
              

          
            
    

 
 
NOTE: The number of sampling
and monitoring locations, the
number of years for monitoring,
and the COCs to be analyzed
are recommended and subject to
change as determined by the
Executive Secretary. These
parameters must be capable of
defining the extent and degree of
contamination, the plume
centerline, if applicable, and the
nature of the contaminant
plume.
               
       
    
    
    
   

    
    
    
   

Plumes < 10,000 ft
2  
     
    
  
Plumes > 10,000 ft
2  
    
    
   
    
     
 
Plumes < 10,000 ft
2 
     
    
  
Plumes > 10,000 ft
2  
    
    
   
    
     
 
                      
          
 
                 
  
        
                    
                      
  
If performed, mark the spaces
provided where applicable:
    
  
   
    
  
   
    
  
   
   
                  
 
          
    
If performed, indicate below and circle the parameters monitored:
       
  
   
    
    

     
Indicate below and circle the parameters monitored:
       
  
   
    
b     

  
  
   
 
           
       
                   

          continued
            
    
 
Use Worksheets #4a
through #4e to document
plume stability and
mass balance.
    

plume stability may not be
possible without monitoring data
 



If plume is not stable or
diminishing, go to next
applicable Option, or submit
Risk Assessment report and
CAP.
    

 



If plume is not stable or
diminishing, go to next
applicable Option, or submit
Risk Assessment report and
CAP.
   
  
 



If plume is not stable or
diminishing, Option 4 may be
required, or submit Risk
Assessment report and CAP.
   
  
 



If plume is not stable or
diminishing, submit Risk
Assessment report and CAP.
 



    
    
    
    
    
    


   


   


   
    

   
  
    
  
   
   
   
   
  
   
    

   
  
    
  
  
  
   
   
   
  

 
    
        
     
      
           
        

          continued
     
                      
                          
                       
       
  


 
 


  
  
   
   
   
  
     
   





















  
   
  
   
  
  
 
  
   
  
   
  
  
 
     
     
 
   
   
   
   
 
   

          continued
                




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

  


     
   

     
   
 
 
 

  
  
  
    
 
 


  
  
  
    
i 

 
i

           

  
 
 

      
    
 
  
   

     
   
    
    
    
       
      
Note         
          
       
 
 
  
  
  
    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 
n  

      
 
  
  
  
  
    

  

     

 
  

    
  

    
 

 



 
 
 
 
 
     
   
 
     
   
 




 

    
   

    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.


 
 
 

    
  

    


 
  

    
  

    


 
 

     


 

  
  
  
    


 

  
  
  
    

 
  
  

  
  
 
 
    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.


 
 



 
  
 
  
  
    
    
   

         
      
     

    
   
 
    

         
      
     

    
   
 
    



 
 


 
 
  
 
  
  
    
    
   

         
      
     

    
   
 
    

         
      
     

    
   
 
    


          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 



 
       

 
 
 
  
  
  
 
  
 
  
  
 
  
 
  

  

         
       

    
   
 
Field measurements are not permissible
         
       

    
   
 
Field measurements are not permissible
 
 

 

       
   
 
       
   
 

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 

   
     
   
     
 
     


 



 


        
         
        
       

        
         
        
       




 





      
   
      i
       
    
      i
 
 

  
  
  
   
 
 

  
  
  
   
  
 
  
  
  
   
 
 

  
  
  
   

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.


 
 
  
 
  
  
    
    
   


 
 





 

    
      
        
      
     (for
shallow aquifers only. Use average and/or
representative values)
       
   
    
      
        
      
     (for
shallow aquifers only. Use average and/or
representative values)
       
   
  

 
     
          


 
 
       

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 

 
 
  
  
  
   
 
 

  
  
  
   

 
 
 
  
      
    
   
 
      
    
   
 
 


 
 
       
   
 
       
   
 
 

 
   


       
   
 
       
   
 
  
 

  
  
  
   

 

  
    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 
   
   
       

 
 

  
  
  
   

 
 
  
  
  
   
      
  

    
 


 
       
 
 
 
    
   
  

  
  
  
   
 
  


       

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 


       
 
 
 
  
  

   
 
 
  
  
  
   
 
 
 
 
 
    

 

 
                    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 
n 
  
 
 
 



      
     
       
 
 
 
  
 




 
                  

 
 
  


   


    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 
 
  
 


     


    

  
  
  



     


    

 
 
 


     


   

 
 
 



     


    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 

 
  
  
 
       

 






    
  
  
 
  
 
 
 
 
 
 
   

 
 
     
  
 


 
   

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
  
 

   
 
  

  
  
  
  
  
   
 
 
 


  
 

 


      
 
 

  

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.


  


 
 

 
  
 
  
  
    
    
   

 
      
  
    
   
 
    

 
      
  
    
   
 
    

 
 

 
 
  
 
  
  
    
    
   

      
       
      
 
    
   
 
    

      
       
      
 
    
   
 
    


          continued
                continued




 
   
Mark the spaces provided,
where applicable
If
applicable


 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 
 


  
 
  
 
  
  
    
   

   

     
      
      
    
   
 
    

     
       
      
    
   
 
    

 

 


   

          continued
                continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 


  
      
  
   
  
   
   
 
   
 
   

   

     
      
     


    

     
      
     
  
    


          continued
                




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

  



     
 
   


       
   
 

 


 

  
  
    

  


 

  
  
    
i 
 
 
i

     

       

  
 
 


     

    
 
  
   

     
   
    
    
    
       
      
Note         
          
       
 
 
 

  
  
    

          continued
                continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 

n 


      
 
  
  
  
  
    

 
 

     

 
 
 

    
  


    
 

 



 
 
 
 
 
      

   


       
   
 




 

    
  


    

          continued
                continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 
 
 

    
  


    


  
 

    
  

    

 
 

     

 

  
  
  
    


 
  
  
  
    
 
 
  

  
  
 
 

    

          continued
                continued




 
   
Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.


 
 


 
 
  
 
  
  
    
    
   

  
      
    
   
    
   
 
    

         
       
     
    
   
 
    



 
 


 
 
  
 
  
  
    
    
   

  
      
    
   
    
   
 
    

         
       
     
    
   
 
    


          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 



 
       

 
 
 
  
  
  
 
  
 
  

  
 
  
 
  

  
 
       
  
    
   
 
Field measurements are not permissible
         
        
    
   
 
Field measurements are not permissible
 
  
         

   
 
       
   
 

          continued
                , continued




 
   
Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 

   
     
   
     
 
     
 
 



  

      
       
      
       
      
        
         
        
       




 
 


    
      

      i
     
      
      i
 
 

  
  
  
   
 
 

  
  
  
   
  
 
  
  
  
   
 
 

  
  
  
   

          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.


 
  
 
 
 





 

      
       
    
 
       
   
       
       
     
       
   
  

 
     
          


 
 
       
 

 
 
  
  
  
   
 
 

  
  
  
   

          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 
 
 
      
     
   
 
      
    
   
 
 


 
 
       

   
 
       
   
 
 

 
   

      

   
 
       
   
 
  

 

  
  
  
   

 

  
    

 
   
   
   


 


  
  
  
    


 

  
  
  
    

          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
      
  

    
 


 
       
 
 
 
    
   
 
 

  
  
  
   
 
 



       
 
 


       
 
 
 
  
  

    
 


 
  
  
    

          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 
 
 
 
    

 

 
                    

 

n 
  

 

 



      
     
      


 
 
 
  
 




 
                  

 
 
  


   
   


    

          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 
 
 
 



   
   


    

 
  

  



     


    

 
 
 


   
   


    

 
 
 




   
   


    

          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 

 
  
  

 

      
 






    
  
 
 
 
 
 
 
 
 
 
    

 
 
    
  
 



 
    
  
 

    

          continued
                , continued




 
   
Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
  

  
  
  
  
  

    
 

 

  


 



  

    
 
 

  



  


 
 

 
  
 
  
  
    
    
   

       
      
    
    
   
 
    

        
      
   
    
   
 
    


          continued
                , continued




 
   
Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.
 
 


 
  
 
  
  
    
    
   

      
       
      
 
    
   
 
    

      
      
     
   
    
   
 
    


 
 

  
 
  
 
  
  
    
   
   

     
       
      
    
   
 
    

     
       
     
 
    
   
 
    


          continued
                , continued




 
  

Mark the spaces provided,
where applicable
If applicable
 
 


 
   
Mark the spaces provided or enter values,where applicable
For Field-Measured parameters, use average and representative values.

 


  

    

 
 


  
      
  
   
  
   
   
 
   
 
   

   

     
       
     
 
    

     
       
     
   
 
    

         
         
    
  
           
   
  
 
 
   
 

         continued
      
            
                  
    
   
  
  
  
   
  
    
  
 
  
   
  
 
  
  
  

B-58
AIR
Inhalation of Vapors
or Particulates
SOIL
Dermal
Contact/Ingestion
GROUNDWATER
Potable Water Use
or Property Boundary
SURFACE WATER
Recreational Use/
Sensitive Habitat
TRANSPORT
MECHANISM
EXPOSURE
PATHWAY
CAUSES
of RELEASE
IMPACTED
MEDIUM
Surface Soil
<3 ft deep**
Free Phase Liquid
Plum e***
Dissolved
Groundwater Plume
Subsurface Soil
>3 ft deep**
Surface soils,
Sediments, or
Surface Water
Storm water/Surface
Water Transport
Mobile Free Phase
Migration
Leaching and/or
Groundwater
Transport
Volatilization to
Indoor Air
Volatilization to
Outdoor Air
Volatilization and
Dust Transport
POTENTIAL
RECEPTORS*
____Product
Storage
(tanks/UST)
____Piping
____Dispenser
____Other
On-site:Residential
Sensitive Habitat
Off-site:Residential
Sensitive Habitat
nonresidential
construction worker
nonresidential
construction worker
Exposed Receptors
Exposed Persons
On-site:Residential
Sensitive Habitat
Off-site:Residential
Sensitive Habitat
nonresidential
construction worker
Groundwater Users
On-site:Residential
Sensitive Habitat
Off-site:Residential
Sensitive Habitat
nonresidential
construction worker
Surface Water Users
On-site:Residential
Sensitive Habitat
Off-site:Residential
Sensitive Habitat
nonresidential
construction worker
nonresidential
None
1. Mark the small boxes if the specified condition is applicable
INSTRUCTIONS
Worksheet #3: Site Conceptual Exposure Model (modified from GSI, 1995)
2. Fill in the shutoff valves to indicate that exposure pathway is NOT complete.
Exposure pathway may not be complete due to source removal, control, and/or treatment.
CLEANUP
OPTIONS
Complete ___Current
Pathway ___Potential
Complete ___Current
Pathway ___Potential
Complete ___Current
Pathway ___Potential
Action Required? Yes__ No__
if YES, list cleanup options below:
_________________________________
_________________________________
Action Required? Yes__ No__
if YES, list cleanup options below:
_________________________________
_________________________________
Action Required? Yes__ No__
if YES, list cleanup options below:
_________________________________
_________________________________
3. For each complete pathway, identify the cleanup options.
(check applicable)
**Evaluate potential for subsurface soil to be excavated and become surface soil
*"Potential" refers to a projection of 5 to 10 years
Notes:
***Free Product is a source that must be eliminated or controlled. See Free Product Removal Report in Subsurface Investigation, Appendix D.
Complete ___Current
Pathway ___Potential
Action Required? Yes__ No__
if YES, list cleanup options below:
_________________________________
_________________________________
nonresidential
construction worker
nonresidential
construction worker
Site Name: __________________________
Site Location: _______________________
Facility ID:_________________


 

Old Teasdale Merc
19 N. Main St., Teasdale, UT
2000143

B-1
Worksheet #4a
Plume Stability Evaluation Procedures and Results

Facility Name and Location: Old Teasdale Merc, 19 North Main Street, Teasdale, UT 84773
Date Completed: May 31, 2023
Facility ID: 2000143
Completed By: Erin Osborn with oversight from Taura Nichols

INSTRUCTIONS
STEP 1
Use this Worksheet 4a to show the final results of your mass balance and plume stability calculations. Complete
Worksheets 4b through 4e, as applicable, to ensure that your final conclusions regarding contaminant reduction
are as accurate as possible.
Discuss groundwater fluctuations, biodegradation capacity, or other phenomena to support your conclusions
regarding plume stability. Discuss the source of data used and show applicable figures in Appendix C.

STEP 2
Check the worksheet(s) below that apply to the site:
__X__ Worksheet 4a: Plume Stability Results (this page)
__X__ Worksheet 4b: Mass Calculations for Dissolved Phase
_ NA_ Worksheet 4c: Mass Calculations for Adsorbed Phase
__X__ Worksheet 4d: Percent of Average Decrease of Dissolved Contaminant Concentrations
__X__ Worksheet 4e: Statistical Evaluation of Plume Stability

STEP 3
Discuss the results of each Worksheet (4b through 4e) as they relate to your Tier 2 Risk Assessment and plume
stability in each medium.
Several lines of evidence support the conclusion that the groundwater plume, as defined by TPH and benzene
concentrations exceeding ISLs, is diminishing.
 Mass Calculations for Dissolved Phase (Worksheet 4b): Dissolved phase TPH and benzene mass calculations were
completed for the period following cessation of the TPET system (4Q2005 through 3Q2023). Over this 18-year
period, masses of TPH-GRO and benzene in the dissolved phase have been reduced by 72.75 percent and 97.58
percent, respectively. The estimated mass of TPH-GRO in the dissolved phase has decreased from 3.1 kg to 0.847 kg.
For dissolved benzene, mass in the dissolved phase has decreased from an initial mass of 0.25 kg to 0.0061 kg in
3Q2023. The calculations were completed using measured groundwater data from the plume, an assumed plume
thickness of 3 feet, and soil porosity values selected from DERR permissible values for silty sand.
 Mass Calculations for Adsorbed Phase (Worksheet 4c): Adsorbed phase mass calculations are not available, as
post-remedial soil samples are limited to one sampling event conducted in 2005. Prior to remediation, offsite soil
concentrations of petroleum-related compounds were below ISLs, except for the onsite source and some locations
near the Site boundary under Main Street.
 Percent of Average Decrease of Dissolved Contaminant Concentrations (Worksheet 4d): The percent reductions
of dissolved contaminant concentrations were calculated for TPH-GRO and benzene for the period following
cessation of the TPET system (3Q2005 through 3Q2023). For TPH-GRO, the average percent reduction is currently
88 percent relative to baseline (i.e., initial post-remedial concentrations measured in 3Q2005). The average
concentration reductions were calculated based on data from 4 groundwater monitoring wells in the plume. Data from
3Q2005, 3Q2012, 3Q2019, and 3Q2023 were used to calculate the average concentration reductions of 58 percent, 87
percent, and 88 percent for the three time periods following initial post-remedial conditions (3Q2005). For benzene,
concentration reductions were calculated using the same four monitoring wells and time periods as for TPH-GRO.
The average percent reduction between 3Q2005 and 3Q2012 was 66 percent; current average percent reduction based
on 3Q2023 data relative to baseline conditions is 97 percent.
 Statistical Evaluation of Plume Stability (Worksheet 4e): TPH-GRO and benzene concentration trends in
groundwater were evaluated over the period since cessation of the TPET system (4Q2005 through 3Q2023) using
linear regression analysis. For TPH-GRO, a significant decreasing concentration trend was observed in the three
evaluated wells, (AGW-1, CGW-12, and FGW-17) with concentrations below ISLs projected by 2019 to 2039.
Attenuation factors for TPH-GRO were similar for each well. For benzene, similar decreasing trends were observed in
the two evaluated wells (AGW-1 and CGW-12). Benzene concentrations are projected to reach ISLs in all wells by
2039.

Worksheet #4b, Dissolved-GRO
Date Completed:  December 26, 2023
Facility and Release ID: 2000143 Person Completing this Worksheet: J. Adams
Outermost Contour Line, mg/L: 1 mg/L (4Q05); 0.1 mg/L (3Q23)
TIME = INITIAL  
GW Area "A"
Enter Plume Length                    
below (feet)
Enter Plume Width                     
below (feet)
Enter Plume 
Thickness               
below (feet) *
Enter Average Conc. 
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
40 15 3 110 0.41 1.805
GW Area "B"
Enter Plume Length                    
below (feet)
Enter Plume Width                     
below (feet)
Enter Plume 
Thickness               
below (feet)
Enter Average Conc. 
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
130 60 3 5.5 0.41 1.083
GW Area "C"
Enter Plume Length                    
below (feet)
Enter Plume Width                     
below (feet)
Enter Plume 
Thickness               
below (feet) *
Enter Average Conc. 
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
180 120 3 0.55 0.41 0.208
TIME=INITIAL: TOTAL MASS IN 
DISSOLVED PHASE SHOWN BELOW 
(kg):
Pounds of TPH-GRO in Dissolved Phase
(lbs)
Gallons of TPH-GRO Contaminated 
Groundwater
(gal)
Gallons of TPH-GRO 
in Dissolved Phase
(gal)
3.10 6.82 484,704 1.10
Mass Area(A) = (thickness of plume in Area A, ft)((Length Area A/2)(Width Area A/2)*3.14)(ave conc in Area A, mg/L)(total porosity)(UMC) 
Ellipse Method of Mass Calculations for Initial and Ending Dissolved Phase (TPH-GRO contoured to the 1 mg/L line)
Facility Name and Location: Old Teasdale Merc, 19 N. Main St., Teasdale, UT
INSTRUCTIONS
1. Evaluate applicable, appropriate and representative individual and/or combined 
constituents (e.g., benzene, total BTEXN, TPH, other) that, for example, exceed Tier 1 
criteria or MCLs.
2. Construct site-specific GW contamination concentrations contour maps, like the example 
shown, for initial and ending times.   Divide the map into discrete sections or "areas" and 
calculate the mass in each area, for each time interval, as shown.
3. If you use this spreadsheet to solve the equations, enter your site-specific data in the 
unshaded cells below.
Mass Area(B) = (thickness of plume in Area B, ft)((Length Area B/2)(Width Area B/2)*3.14))-(Length Area A/2)(Width Area A/2)*3.14)(ave. concen. Area B, 
mg/L)(total porosity)(UMC)
Mass Area(C) = (thickness of plume in Area C, ft)((Length Area C/2)(Width Area C/2)*3.14))-(Length Area B/2)(Width Area B/2)*3.14)(ave. concen. Area C, 
mg/L)(total porosity)(UMC)
Unit Mass Conversion = (1000 L/m3)(0.02832 m^3/ft3)(1g/1000mg)(1kg/1000g)
GW: FINAL % REDUCTION (+) OR INCREASE (-) shown below
72.65%
4. Calculate the total mass in the dissolved phase, in each area, at TIME = INITIAL. Then, 
calculate the total mass in the dissolved phase, in each area, for TIME = END.  Identify your 
INITIAL and ENDING times.
5. The plume is stable if the ending mass is the same or similar to the initial mass.  The 
plume is decreasing if the ending mass is less than the initial mass.
6. The FINAL PERCENT REDUCTION (+) or INCREASE ( - ) of mass is shown.
7. If you are manually calculating mass, use the equations below.
EQUATIONS
Worksheet #4b, Dissolved-GRO
TIME = END
GW Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
30 15 3 10.5 0.41 0.129
GW Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
110 40 3 5.5 0.41 0.594
GW Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
180 70 3 0.55 0.41 0.123
TIME=END: TOTAL
MASS IN DISSOLVED PHASE
SHOWN BELOW (kg):
Pounds of TPH-GRO in Dissolved Phase
(lbs)
Gallons of TPH-GRO Contaminated
Groundwater
(gal)
Gallons of TPH-GRO
in Dissolved Phase
(gal)
0.847 1.87 282,744 0.30
*Use 3 feet for GW plume thickness unless you have evidence such as vertical sampling, to prove otherwise.
Worksheet #4b, Dissolved-Benzene
Date Completed: December 26, 2023
Facility and Release ID: 2000143 Person Completing this Worksheet: J. Adams
Outermost Contour Line, mg/L: 1 µg/L (4Q05); 0.1 µg/L (3Q23)
TIME = INITIAL
GW Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
40 20 3 1.05 0.41 0.023
GW Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
145 100 3 0.55 0.41 0.206
GW Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
220 130 3 0.055 0.41 0.021
GW Area "D"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
260 160 3 0.0055 0.41 0.002
TIME=INITIAL: TOTAL MASS IN
DISSOLVED PHASE SHOWN BELOW
(kg):
Pounds of Benzene in Dissolved Phase
(lbs)
Gallons of Benzene Contaminated
Groundwater
(gal)
Gallons of Benzene in
Dissolved Phase
(gal)
0.25 0.55 641,784 0.09
Ellipse Method of Mass Calculations for Initial and Ending Dissolved Phase (Benzene contoured to the 1 µg/L line)
Facility Name and Location: Old Teasdale Merc, 19 N. Main St., Teasdale, UT
INSTRUCTIONS
1. Evaluate applicable, appropriate and representative individual and/or combined
constituents (e.g., benzene, total BTEXN, TPH, other) that, for example, exceed Tier 1
criteria or MCLs.
2. Construct site-specific GW contamination concentrations contour maps, like the example
shown, for initial and ending times. Divide the map into discrete sections or "areas" and
calculate the mass in each area, for each time interval, as shown.
3. If you use this spreadsheet to solve the equations, enter your site-specific data in the
unshaded cells below.
4. Calculate the total mass in the dissolved phase, in each area, at TIME = INITIAL. Then,
calculate the total mass in the dissolved phase, in each area, for TIME = END. Identify your
INITIAL and ENDING times.
5. The plume is stable if the ending mass is the same or similar to the initial mass. The
plume is decreasing if the ending mass is less than the initial mass.
6. The FINAL PERCENT REDUCTION (+) or INCREASE ( - ) of mass is shown.
GW: FINAL % REDUCTION (+) OR INCREASE (-) shown below
97.58%
7. If you are manually calculating mass, use the equations below.
EQUATIONS
Mass Area(A) = (thickness of plume in Area A, ft)((Length Area A/2)(Width Area A/2)*3.14)(ave conc in Area A, mg/L)(total porosity)(UMC)
Mass Area(B) = (thickness of plume in Area B, ft)((Length Area B/2)(Width Area B/2)*3.14))-(Length Area A/2)(Width Area A/2)*3.14)(ave. concen. Area B,
mg/L)(total porosity)(UMC)
Mass Area(C) = (thickness of plume in Area C, ft)((Length Area C/2)(Width Area C/2)*3.14))-(Length Area B/2)(Width Area B/2)*3.14)(ave. concen. Area C,
mg/L)(total porosity)(UMC)
Unit Mass Conversion = (1000 L/m
3)(0.02832 m^3/ft
3)(1g/1000mg)(1kg/1000g)
Worksheet #4b, Dissolved-Benzen
TIME = END
GW Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
120 30 3 0.055 0.41 0.0054
GW Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
155 45 3 0.0055 0.41 0.00051
GW Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume
Thickness
below (feet)*
Enter Average Conc.
below (mg/L)
Enter Porosity Mass in Dissolved Phase shown below (kg)
195 80 3 0.00055 0.41 0.00013
TIME=END: TOTAL
MASS IN DISSOLVED PHASE
SHOWN BELOW (kg):
Pounds of Benzene in Dissolved Phase
(lbs)
Gallons of Benzene Contaminated
Groundwater
(gal)
Gallons of Benzene in
Dissolved Phase
(gal)
0.0061 0.013 350,064 0.0021
*Use 3 feet for GW plume thickness unless you have evidence such as vertical sampling, to prove otherwise.
Worksheet #4c, Adsorbed-GRO
Date Completed:
Facility and Release ID: Person Completing this Worksheet:
Outermost Contour Line, mg/kg:
Example of Adsorbed Phase INSTRUCTIONS
Concentration Map at TIME=INITIAL
Soil Mass % decrease or increase: 1-(mass END/mass INITIAL)
UMC, Unit Mass Conversion = (28320 cm^3/ft^3)(1kg/1000g)(1g/1000mg)(1kg/1000g)
FINAL RESULTS OF SOIL MASS REDUCTION OR INCREASE
MASS SUMMARY (kg)
Total Mass in Soil at
Time = INITIAL (kg)
Total Mass in Soil
at Time = END
(kg)
Final Mass Reduction/Increase in Soil:
0.00 0.00
Soil Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
TIME=INITIAL:
TOTAL MASS IN Adsorbed PHASE
SHOWN BELOW (kg):
Pounds TPH in
Soil Phase Shown
Below (lbs)
Gallons TPH in
Soil Phase Shown
Below (gal)
Cubic
Yards TPH-
Contaminated
Soil
(yd3)
0 0 0 0
Example Ellipse Method of Mass Calculations for Initial and Ending Adsorbed Phase Constituent(s) Evaluated: TPH to the 10 mg/kg
contour line
Mass Area A = (thickness of soil plume in Area A, ft)((Length Area A/2)(Width Area A/2) * 3.14)(ave soil conc in Area A, mg/kg)(bulk
density)(UMC)
Mass Area B = (thickness of soil plume in Area B, ft)[(Length Area B/2)(Width Area B/2) * 3.14) - (Length Area A/2)(Width Area A/2) *
3.14)](ave soil conc in Area B, mg/kg)(bulk density)(UMC)
#DIV/0!
TIME = INITIAL:
Facility Name and Location:
NOTE: Adsorbed phase mass calculations are not available, as post-remedial soil samples are limited to one sampling event conducted in 2005. See Worksheet
#1 Section E for more information.
1. Evaluate applicable, appropriate and representative individual and/or combined constituents (e.g., benzene, total BTEXN, TPH,
other) that, for example, exceed Tier 1 criteria or ISLs. Identify constituent(s) evaluated.
2. Construct site-specific soil contamination concentrations contour maps, like the example shown, for initial and ending times. Divide
the map into discrete sections or "areas" and calculate the mass in each area, for each time interval, as shown.
3. If you use this spreadsheet to solve the equations, enter your site-specific data in the unshaded cells below.
4. First, calculate the total mass in the adsorbed phase, in each area, at TIME = INITIAL. Then, calculate the total mass in adsorbed
phase, for each time interval, in each area, for TIME = END. Identify your INITIAL and ENDING times.
5. The plume is stable if the ending mass is the same as the initial mass. The plume is decreasing if the ending mass is less than the
initial mass. The plume is increasing if the ending mass is greater than the initial mass.
6. The FINAL PERCENT REDUCTION (+) OR INCREASE ( - ) of mass is shown in the cell below.
Mass Area C = (thickness of soil plume in Area C, ft)[(Length Area C/2)(Width Area C/2) * 3.14) - (Length Area B/2)(Width Area B/2) *
3.14)](ave soil conc in Area C, mg/kg)(bulk density)(UMC)
7. If you are manually calculating mass, use the equations below.
Worksheet #4c, Adsorbed-GRO
Soil Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
TIME=END:
TOTAL MASS IN ADSORBED
PHASE SHOWN BELOW (kg):
Pounds TPH in
Soil Phase Shown
Below (lbs)
Gallons TPH in
Soil Phase Shown
Below (gal)
Cubic
Yards TPH-
Contaminated
Soil
(yd3)
0.00 0.000 0.000 0
TIME = END Enter Ending Date Here:
Worksheet #4c, Adsorbed-Benz
Date Completed:
Facility and Release ID: Person Completing this Worksheet:
Outermost Contour Line, mg/kg:
Example of Adsorbed Phase INSTRUCTIONS
Concentration Map at TIME=INITIAL
Soil Mass % decrease or increase: 1-(mass END/mass INITIAL)
UMC, Unit Mass Conversion = (28320 cm^3/ft^3)(1kg/1000g)(1g/1000mg)(1kg/1000g)
FINAL RESULTS OF SOIL MASS REDUCTION OR INCREASE
MASS SUMMARY (kg)
Total Mass in Soil at
Time = INITIAL (kg)
Total Mass in Soil
at Time = END
(kg)
Final Mass Reduction/Increase in Soil:
0.00 0.00
Soil Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
TIME=INITIAL:
TOTAL MASS IN Adsorbed PHASE
SHOWN BELOW (kg):
Pounds TPH in
Soil Phase Shown
Below (lbs)
Gallons TPH in
Soil Phase Shown
Below (gal)
Cubic
Yards TPH-
Contaminated
Soil
(yd3)
0 0 0 0
Example Ellipse Method of Mass Calculations for Initial and Ending Adsorbed Phase Constituent(s) Evaluated: TPH to the 10 mg/kg contour line
Facility Name and Location:
1. Evaluate applicable, appropriate and representative individual and/or combined constituents (e.g., benzene, total BTEXN, TPH,
other) that, for example, exceed Tier 1 criteria or ISLs. Identify constituent(s) evaluated.
2. Construct site-specific soil contamination concentrations contour maps, like the example shown, for initial and ending times. Divide
the map into discrete sections or "areas" and calculate the mass in each area, for each time interval, as shown.
3. If you use this spreadsheet to solve the equations, enter your site-specific data in the unshaded cells below.
4. First, calculate the total mass in the adsorbed phase, in each area, at TIME = INITIAL. Then, calculate the total mass in adsorbed
phase, for each time interval, in each area, for TIME = END. Identify your INITIAL and ENDING times.
NOTE: Adsorbed phase mass calculations are not available, as post-remedial soil samples are limited to one sampling event conducted in 2005. See Worksheet
#1 Section E for more information.
#DIV/0!
TIME = INITIAL:
5. The plume is stable if the ending mass is the same as the initial mass. The plume is decreasing if the ending mass is less than the
initial mass. The plume is increasing if the ending mass is greater than the initial mass.
6. The FINAL PERCENT REDUCTION (+) OR INCREASE ( - ) of mass is shown in the cell below.
7. If you are manually calculating mass, use the equations below.
Mass Area A = (thickness of soil plume in Area A, ft)((Length Area A/2)(Width Area A/2) * 3.14)(ave soil conc in Area A, mg/kg)(bulk
density)(UMC)
Mass Area B = (thickness of soil plume in Area B, ft)[(Length Area B/2)(Width Area B/2) * 3.14) - (Length Area A/2)(Width Area A/2) *
3.14)](ave soil conc in Area B, mg/kg)(bulk density)(UMC)
Mass Area C = (thickness of soil plume in Area C, ft)[(Length Area C/2)(Width Area C/2) * 3.14) - (Length Area B/2)(Width Area B/2) *
3.14)](ave soil conc in Area C, mg/kg)(bulk density)(UMC)
Worksheet #4c, Adsorbed-Benz
Soil Area "A"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "B"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
Soil Area "C"
Enter Plume Length
below (feet)
Enter Plume Width
below (feet)
Enter Plume Thickness
below (feet)*
Enter Average Conc.
below (mg/kg)
Bulk Density
(g/cm^3)
Mass in Adsorbed Phase shown below (kg)
NA NA NA NA NA 0.000
TIME=END:
TOTAL MASS IN ADSORBED
PHASE SHOWN BELOW (kg):
Pounds TPH in
Soil Phase Shown
Below (lbs)
Gallons TPH in
Soil Phase Shown
Below (gal)
Cubic
Yards TPH-
Contaminated
Soil
(yd3)
0.00 0.000 0.000 0
TIME = END Enter Ending Date Here:

B-65
WORKSHEET #4d
Determining Percent Decrease in Dissolved Concentrations
Constituent(s) Evaluated: _________________________

Facility Name and Location: Date Completed:
Facility ID: Completed By:

INSTRUCTIONS: Example of Calculating Percent Reduction of Dissolved Contamination Across a Site.
Enter your data in the UNSHADED cells

Enter Well # below
Enter
Concentration at
Time 1
(= baseline
concentration)
Enter
Concentration at
Time 2
Enter
Concentration at
Time 3
Enter
Concentration at
Time 4
MW-1
MW-2
MW-3
MW-4
ENTER TOTAL # OF
WELLS LISTED
ABOVE

TOTAL
CONCENTRATION
OF ALL WELLS

AVERAGE
CONCETNRATION
OF ALL WELLS

TOTAL AVERAGE
CONCENTRATION

AVERAGE %

FORMULAS: AVERAGE % REDUCTION = (concentration average at TIME = 1) – (concentration
average at TIME = 2)
Old Teasdale Merc, 19 N. Main St. Teasdale, UT
2000143
Dec. 21, 2023
J. Adams
TPH - GRO
(AGW-1)
(CGW-12)
(FGW-17)
(DGW-16)
4
3Q 2005 3Q 2012 3Q 2019 3Q 2023
35,000 13,000 4,900 805
59,000 26,000 7,100 11,100
7,000 2,100 1,300 834
4,300 3,200
88 <31.4
105,300
26,325
44,300
11,075
13,388
3,347
12,770
3,193
100%42%13% 12%
--- 58%
87%88%
Concentrations in µg/L

B-65
WORKSHEET #4d
Determining Percent Decrease in Dissolved Concentrations
Constituent(s) Evaluated: _________________________

Facility Name and Location: Date Completed:
Facility ID: Completed By:

INSTRUCTIONS: Example of Calculating Percent Reduction of Dissolved Contamination Across a Site.
Enter your data in the UNSHADED cells

Enter Well # below
Enter
Concentration at
Time 1
(= baseline
concentration)
Enter
Concentration at
Time 2
Enter
Concentration at
Time 3
Enter
Concentration at
Time 4
MW-1
MW-2
MW-3
MW-4
ENTER TOTAL # OF
WELLS LISTED
ABOVE

TOTAL
CONCENTRATION
OF ALL WELLS

AVERAGE
CONCETNRATION
OF ALL WELLS

TOTAL AVERAGE
CONCENTRATION

AVERAGE %

FORMULAS: AVERAGE % REDUCTION = (concentration average at TIME = 1) – (concentration
average at TIME = 2)
Old Teasdale Merc, 19 N. Main St. Teasdale, UT
2000143
Dec. 21, 2023
J. Adams
Benzene
(AGW-1)
(CGW-12)
(FGW-17)
(DGW-16)
4
3Q 2005 3Q 2012 3Q 2019 3Q 2023
1,100 400 140 78.9
2,300 630 99 91.8
1,000 10 0.8 0.530
1,100 810
0.7 <0.0941
5,500
1,375
1,850
463
241
60
171.3
42.8
100%34%4% 3%
--- 66%
96%97%
Concentrations in µg/L
Worksheet #4e
Summary of Statistical Analysis of Groundwater Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Minimum
Concentration
(mg/L)
Maximum
Concentration
(mg/L)
Concentration
Measured Most
Recently (mg/L)
% of Data
Above
Laboratory
Reporting
Limit
Start Date End Date
Coefficient of
Determination, R-
squared2
p-value of
Correlation
(Significance
of Slope)
Attenuation
Half-life
(days)
Trend
Direction
Significance
of Trend3
Projected
Year to
Screening
Level
TPH-GRO (post-treatment) AGW-1 1 0.81 35 0.8 100 8/16/2005 11/8/2023 0.48 <0.01 1,697 Decreasing Significant 2028
TPH-GRO (post-treatment) FGW-17 1 0.67 7.1 0.8 100 9/20/2005 11/8/2023 0.85 <0.01 2,124 Decreasing Significant 2019
TPH-GRO (post-treatment) CGW-12 1 3.5 120 11.1 100 8/16/2005 11/8/2023 0.52 <0.01 2,111 Decreasing Significant 2039
Benzene (post-treatment) AGW-1 0.005 0.003 1.1 0.08 100 8/16/2005 11/8/2023 0.33 <0.01 1,710 Decreasing Significant 2039
Benzene (post-treatment) CGW-12 0.005 0.008 2.3 0.092 100 8/16/2005 11/8/2023 0.53 <0.01 1,242 Decreasing Significant 2035
Notes, Abbreviations and Assumptions:
mg/L = milligrams per liter
1 Utah Department of Environmental Quality Initial Screening Levels
2 Linear regression analysis with R2 values <0.1 are defined as having no apparent trend (No Trend).
3 Statistically significant trend defined as having p-value 
Data in italics ND taken at reporting limit/reported value
Data is underlined Qualified data converted to reported value
NotesWellConstituentUDEQ ISLs
(mg/L)1
Data Range Linear Regression Analysis
Page 1 of 1
Sample Information
Sample Location AGW-1
Constituent TPH-GRO (post-treatment)TPH-GRO (post-treatment)
Data
Sample Date Concentration LN Concentration
(mg/L)
8/16/2005 3535 3.56
11/16/2005 1414 2.64
2/21/2006 2424 3.18
5/9/2006 2020 3.00
2/15/2007 1515 2.71
7/9/2007 1111 2.40
2/27/2008 1414 2.64
7/8/2008 9 2.20
2/10/2009 1515 2.71
8/3/2009 1919 2.94
3/1/2010 1717 2.83
8/2/2010 2424 3.18
2/10/2011 2020 3.00
8/18/2011 2323 3.14
3/8/2012 1414 2.64
8/28/2012 1313 2.56
3/28/2013 1212 2.48
8/21/2013 1818 2.89
3/19/2014 1414 2.64
9/23/2014 1717 2.83
3/26/2015 6.7 1.90
9/24/2015 1515 2.71
9/29/2016 9.6 2.26
8/27/2017 8.7 2.16
11/7/2018 0.84 -0.17 Notes:
9/12/2019 4.9 1.59 ND taken at reporting limit/reported valueND taken at reporting limit/reported value
9/29/2020 1.87 0.63 Qualified data converted to reported valueQualified data converted to reported value
10/28/2021 1.80 0.59
11/8/2023 0.81 -0.22 Data quality
Total # of data points used in regressionTotal # of data points used in regression 2929
# of nondetects 0
% of data as detects 100
Results
Coefficient of Determination (RCoefficient of Determination (R
2) =0.4773
p-Value =2.91E-07
Attenuation Rate in Groundwater (K) =Attenuation Rate in Groundwater (K) =0.0004 days-1-1
Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =0.0003 days-1-1
Chemical Half Life in Groundwater (tChemical Half Life in Groundwater (t1/2) =1.70E+03 days
Date Screening Level ReachedDate Screening Level Reached
Screening Level 1
LN Screening Level 0.0
Intercept 19.139
Slope -0.0004
Date to Screening Level 5/3/2028
Abbreviations and NotesAbbreviations and Notes
mg/l = micrograms per litermg/l = micrograms per liter
LN = Natural Logarithm
AGW-1, TPH-GRO (post-treatment)AGW-1, TPH-GRO (post-treatment)
y = -0.0004x + 17.281
R² = 0.4773
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
5/
2
8
/
2
0
0
5
2/
2
2
/
2
0
0
8
11
/
1
8
/
2
0
1
0
8/
1
4
/
2
0
1
3
5/
1
0
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1
6
2/
4
/
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1
9
10
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LN Concentration LN Screening Level Linear (LN Concentration)
Worksheet #4e Statistical Evaluation of Plume Stability
Sample Information
Sample Location FGW-17
Constituent TPH-GRO (post-treatment)TPH-GRO (post-treatment)
Data
Sample Date Concentration LN Concentration
(mg/L)
09/20/05 7.00 1.95
11/16/05 6.90 1.93
02/21/06 7.10 1.96
05/08/06 5.10 1.63
02/15/07 4.80 1.57
07/09/07 3.60 1.28
02/27/08 4.20 1.44
07/08/08 2.80 1.03
02/10/09 2.60 0.96
08/03/09 3.80 1.34
03/01/10 3.00 1.10
08/02/10 2.50 0.92
02/11/11 2.90 1.06
08/18/11 2.30 0.83
03/08/12 2.70 0.99
08/29/12 2.10 0.74
3/28/2013 1.60 0.47
8/21/2013 2.20 0.79
3/19/2014 1.40 0.34
9/23/2014 1.30 0.26
3/26/2015 1.10 0.10
9/24/2015 1.70 0.53
9/29/2016 2.30 0.83
8/30/2017 0.72 -0.33
11/7/2018 1.00 0.00 Notes:
9/12/2019 1.30 0.26 ND taken at reporting limit/reported valueND taken at reporting limit/reported value
9/29/2020 0.88 -0.13 Qualified data converted to reported valueQualified data converted to reported value
10/27/2021 1.01 0.01
9/28/2022 0.665 -0.41 Data quality
11/8/2023 0.834 -0.18 Total # of data points used in regressionTotal # of data points used in regression 3030
# of nondetects 0
% of data as detects 100
Results
Coefficient of Determination (RCoefficient of Determination (R
2) =0.8474
p-Value =1.35E-13
Attenuation Rate in Groundwater (K) =Attenuation Rate in Groundwater (K) =0.0003 days-1-1
Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =0.0003 days-1-1
Chemical Half Life in Groundwater (tChemical Half Life in Groundwater (t1/2) =2.12E+03 days
Date Screening Level ReachedDate Screening Level Reached
Screening Level 1
LN Screening Level 0.0
Intercept 14.247
Slope -0.0003
Date to Screening Level 7/20/2019
Abbreviations and NotesAbbreviations and Notes
mg/l = milligrams per liter
LN = Natural Logarithm
FGW-17, TPH-GRO (post-treatment)FGW-17, TPH-GRO (post-treatment)
y = -0.0003x + 14.89
R² = 0.8474
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
05
/
2
8
/
0
5
02
/
2
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11
/
1
8
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08
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4
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1
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05
/
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1
6
02
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LN Concentration LN Screening Level Linear (LN Concentration)
Worksheet #4e Statistical Evaluation of Plume Stability
Sample Information
Sample Location CGW-12
Constituent TPH-GRO (post-treatment)TPH-GRO (post-treatment)
Data
Sample Date Concentration LN Concentration
(mg/L)
8/16/2005 5959 4.08
11/17/2005 120 4.79
2/21/2006 4949 3.89
5/9/2006 1717 2.83
2/15/2007 4444 3.78
7/9/2007 3939 3.66
2/27/2008 4141 3.71
7/8/2008 3232 3.47
2/10/2009 4444 3.78
8/3/2009 4545 3.81
3/8/2012 4141 3.71
8/28/2012 2626 3.26
3/28/2013 5959 4.08
3/19/2014 7676 4.33
3/26/2015 3838 3.64
9/29/2016 1515 2.71
8/27/2017 1414 2.64
11/8/2018 3.5 1.25
9/12/2019 7.1 1.96
9/29/2020 8.67 2.16
10/28/2021 10.3 2.33
9/28/2022 4.85 1.58
11/8/2023 11.1 2.41
Notes:
ND taken at reporting limit/reported valueND taken at reporting limit/reported value
Qualified data converted to reported valueQualified data converted to reported value
Data quality
Total # of data points used in regressionTotal # of data points used in regression 2323
# of nondetects 0
% of data as detects 100
Results
Coefficient of Determination (RCoefficient of Determination (R
2) =0.5160
p-Value =1.15E-05
Attenuation Rate in Groundwater (K) =Attenuation Rate in Groundwater (K) =0.0003 days-1-1
Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =0.0002 days-1-1
Chemical Half Life in Groundwater (tChemical Half Life in Groundwater (t1/2) =2.11E+03 days
Date Screening Level ReachedDate Screening Level Reached
Screening Level 1
LN Screening Level 0.0
Intercept 16.787
Slope -0.0003
Date to Screening Level 12/25/2039
Abbreviations and NotesAbbreviations and Notes
mg/l = milligrams per liter
LN = Natural Logarithm
CGW-12, TPH-GRO (post-treatment)CGW-12, TPH-GRO (post-treatment)
y = -0.0003x + 16.857
R² = 0.5160
0.0
1.0
2.0
3.0
4.0
5.0
6.0
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LN Concentration LN Screening Level Linear (LN Concentration)
Worksheet #4e Statistical Evaluation of Plume Stability
Sample Information
Sample Location AGW-1
Constituent Benzene (post-treatment)Benzene (post-treatment)
Data
Sample Date Concentration LN Concentration
(mg/L)
8/16/2005 1.1 0.10
11/16/2005 0.046 -3.08
2/21/2006 1 0.00
5/9/2006 0.95 -0.05
2/15/2007 0.32 -1.14
7/9/2007 0.4 -0.92
2/27/2008 0.77 -0.26
7/8/2008 0.63 -0.46
2/10/2009 0.7 -0.36
8/3/2009 0.6 -0.51
3/1/2010 0.69 -0.37
8/2/2010 1.1 0.10
2/10/2011 0.32 -1.14
8/18/2011 0.57 -0.56
3/8/2012 0.57 -0.56
8/28/2012 0.4 -0.92
3/28/2013 0.48 -0.73
8/21/2013 0.57 -0.56
3/19/2014 0.38 -0.97
9/23/2014 0.17 -1.77
3/26/2015 0.1 -2.30
9/24/2015 0.16 -1.83
9/29/2016 0.19 -1.66
8/27/2017 0.14 -1.97
11/7/2018 0.003 -5.81 Notes:
9/12/2019 0.14 -1.97 ND taken at reporting limit/reported valueND taken at reporting limit/reported value
9/29/2020 0.133 -2.02 Qualified data converted to reported valueQualified data converted to reported value
10/28/2021 0.0834 -2.48
11/8/2023 0.0789 -2.54 Data quality
Total # of data points used in regressionTotal # of data points used in regression 2929
# of nondetects 0
% of data as detects 100
Results
Coefficient of Determination (RCoefficient of Determination (R
2) =0.3276
p-Value =4.23E-04
Attenuation Rate in Groundwater (K) =Attenuation Rate in Groundwater (K) =0.0004 days-1-1
Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =0.0002 days-1-1
Chemical Half Life in Groundwater (tChemical Half Life in Groundwater (t1/2) =1.71E+03 days
Date Screening Level ReachedDate Screening Level Reached
Screening Level 0.005
LN Screening Level -5.3
Intercept 15.419
Slope -0.0004
Date to Screening Level 12/8/2039
Abbreviations and NotesAbbreviations and Notes
mg/l = milligrams per liter
LN = Natural Logarithm
AGW-1, Benzene (post-treatment)AGW-1, Benzene (post-treatment)
y = -0.0004x + 16.211
R² = 0.3276
-7.0
-6.0
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
5/
2
8
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LN Concentration LN Screening Level Linear (LN Concentration)
Worksheet #4e Statistical Evaluation of Plume Stability
Sample Information
Sample Location CGW-12
Constituent Benzene (post-treatment)Benzene (post-treatment)
Data
Sample Date Concentration LN Concentration
(mg/L)
8/16/2005 2.3 0.83
11/17/2005 0.6 -0.51
2/21/2006 1.1 0.10
5/9/2006 1.3 0.26
2/15/2007 1.4 0.34
7/9/2007 2 0.69
2/27/2008 1.4 0.34
7/8/2008 1.7 0.53
2/10/2009 1.7 0.53
8/3/2009 2 0.69
3/8/2012 0.7 -0.36
8/28/2012 0.63 -0.46
3/28/2013 2.1 0.74
3/19/2014 0.34 -1.08
3/26/2015 1.7 0.53
9/29/2016 0.077 -2.56
8/30/2017 0.63 -0.46
11/8/2018 0.008 -4.83
9/12/2019 0.099 -2.31
9/29/2020 0.116 -2.15
10/28/2021 0.0767 -2.57
9/28/2022 0.058 -2.85
11/8/2023 0.0918 -2.39
Notes:
ND taken at reporting limit/reported valueND taken at reporting limit/reported value
Qualified data converted to reported valueQualified data converted to reported value
Data quality
Total # of data points used in regressionTotal # of data points used in regression 2323
# of nondetects 0
% of data as detects 100
Results
Coefficient of Determination (RCoefficient of Determination (R
2) =0.5266
p-Value =6.54E-06
Attenuation Rate in Groundwater (K) =Attenuation Rate in Groundwater (K) =0.0006 days-1-1
Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =Attenuation Rate in Groundwater at 90% confidence (K) =0.0004 days-1-1
Chemical Half Life in Groundwater (tChemical Half Life in Groundwater (t1/2) =1.24E+03 days
Date Screening Level ReachedDate Screening Level Reached
Screening Level 0.005
LN Screening Level -5.3
Intercept 22.340
Slope -0.0006
Date to Screening Level 7/30/2035
Abbreviations and NotesAbbreviations and Notes
mg/l = milligrams per liter
LN = Natural Logarithm
CGW-12, Benzene (post-treatment)CGW-12, Benzene (post-treatment)
y = -0.0006x + 23.155
R² = 0.5266
-6.0
-5.0
-4.0
-3.0
-2.0
-1.0
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Worksheet #4e Statistical Evaluation of Plume Stability
Appendix C
Tables

       
      
                        
                    
        
                
    
       
  
      
          
    
    
    
       
         
     
    
  
 

     
(Check boxes below for the applicable condition).


   
  
 
 
  
 
 
 


 
 
 
 
 

  

 








 
















 
 
 



  

    
  
    
    
  
    
      
  
    
    
  
    
    
  
    
      
  
    
  

    
              
                

       
      
                        
                    
        
                
    
       
  
     
         
    
    
    
       
         
     
     
  
 

     
(Check boxes below for the applicable condition).


   
  
 
 
 

 
 
 
 

 
 
 
 
 
 

  

 



 
 

 
 
 





 
 

 
 

 
 



 
 
 



  

    
  
    
    
  
    
      
  
    
    
  
    
    
  
    
      
  
    
  

    
              
                          
       
         
                        

      
                          
                      
        
                
    
       
  
     
          
    
     
    
  
         
       
         
     
     
  
 

     
(Check boxes below for the applicable condition and enter SSCL in applicable locations).



 
 
 
 
  
 
 


  
 
 
 
 
 

  

 



 
 

 
 
 





 
 

 
 

 
 



 
 
 



 
 
           
            
             
           
            
     
       
  

 
   
              
                     
                    
            
TABLE C-2
Soil Analytical Results
Teasdale Mercantile Site
19 North Main Street, Teasdale, Utah
Sample
Location
Date
Sampled
Depth
(feet bgs)PID (ppm)TPH-GRO
(mg/Kg)
Benzene
(mg/Kg)
Toluene
(mg/Kg)
Ethyl
Benzene
(mg/Kg)
Total
Xylenes
(mg/Kg)
MTBE
(mg/Kg)
Naphth-
alene
(mg/Kg)
Lead
(mg/Kg)
Soil
Moisture
(%)
150 0.2 9 5 142 0.3 51
1500 0.9 25 23 142 0.3 51
AGW-1 11/08/94 10 903 29 <0.010 0.0126 0.080 0.132 -- -- -- --
AGW-1 11/08/94 30 1,564 10,100 38 352 68.4 453 -- -- -- --
AGW-1 11/08/94 35 1,559 NA 37.5 335 59 376 -- -- -- --
AGW-1 11/08/94 48 154 27.4 <0.010 0.194 0.137 1.060 -- -- -- --
AGW-2 11/09/94 15 2,091 1,260 0.665 20.6 6.71 50.3 -- -- -- --
AGW-2 11/09/94 20 2,377 NA 1.14 6.06 2.18 17.2 -- -- -- --
AGW-2 11/09/94 25 1,154 135 0.172 0.487 0.330 1.47 -- -- -- --
AGW-2 11/09/94 53 832 38.3 0.208 0.874 0.467 3.27 -- -- -- --
AGW-3 11/10/94 15 0 <10 <0.005 <0.005 <0.005 <0.015 -- -- -- --
AGW-3 11/10/94 25 12 <10 <0.005 <0.005 <0.005 <0.015 -- -- -- --
AGW-3 11/10/94 40 0 <10 <0.005 <0.005 <0.005 <0.015 -- -- -- --
AGW-4 11/10/94 20 55 <10 <0.005 <0.005 <0.005 <0.015 -- -- -- --
AGW-4 11/10/94 30 1,909 19.9 0.0236 0.130 0.459 0.332 -- -- -- --
AGW-4 11/10/94 40 1,492 310 0.131 1.040 0.669 4.57 -- -- -- --
BGW-5 09/04/98 23 to 25 1,093 280 0.031 0.11 <0.022 0.6 <0.022 0.33 -- 23
BGW-6 09/01/98 23 to 25 36 <0.17 <0.008 <0.017 <0.017 0.022 <0.017 <0.033 -- 4
BGW-6 09/01/98 28 to 30 378 0.23 <0.0026 0.013 <0.0052 0.030 <0.0052 <0.010 -- 4
BGW-6 09/01/98 33 to 35 427 0.35 0.025 0.066 <0.0071 0.081 <0.0071 <0.014 -- 13
BGW-7 09/03/98 33 to 35 >2,500 790 0.73 11 0.91 37 <0.29 3.1 -- 13
BGW-8 09/02/98 18 to 20 25 <0.076 <0.003 <0.007 <0.007 0.017 <0.007 <0.015 -- 14
BGW-8 09/02/98 28 to 30 0 <0.050 <0.0026 <0.005 <0.005 <0.005 <0.005 <0.010 -- 10
BGW-9 09/02/98 28 to 30 33 <0.16 <0.008 <0.016 <0.016 0.040 <0.016 <0.033 -- 5
BGW-9 09/02/98 35 to 37 >2,500 28 <0.039 0.36 0.34 4.4 <0.078 0.57 -- 10
BVE-1 09/04/98 8 to 10 >2,500 3300 <3.1 0.44 <6.3 320 <6.3 28 -- 20
CGW-10 09/29/98 32 to 34 3.7 0.16 0.048 0.038 <0.0072 0.0085 -- <0.015 -- 18
CGW-11 09/30/98 35 to 37 3.5 0.15 0.053 0.052 <0.0049 0.022 -- <0.0099 -- 19
CGW-11 09/30/98 65 to 67 3.5 <0.042 0.011 0.0084 <0.0042 <0.0042 -- <0.0083 -- 16
CGW-12 09/30/98 40 to 42 3.2 <0.066 0.011 0.013 <0.0066 <0.0066 -- <0.014 -- 12
CGW-13 10/01/98 20 to 22 1.2 0.10 0.0051 0.012 <0.0060 0.013 -- <0.012 -- 17
CGW-13 10/01/98 30 to 32 1.3 <0.060 0.0058 0.0063 <0.0060 <0.0060 -- <0.012 -- 9
CGW-13 10/01/98 40 to 42 68.1 0.77 0.012 0.036 <0.0097 0.057 -- <0.020 -- 8
CVE-2 10/01/98 10 to 12 >2,500 5700 <0.62 <1.2 <1.2 160 -- 13E -- 19
CVE-2 10/01/98 33 to 35 >2,500 3700 45 340E 79 750E -- 6.9 -- 12
CVE-2 10/01/98 46 to 48 >2,500 110 0.072 1.1 0.59 7.1E -- 0.64 -- 13
DGW-14 12/09/98 33 to 35 0 <20 <0.1 <0.1 <0.1 <0.1 -- -- -- 15
DGW-14 12/09/98 40 to 42 0 <20 <0.1 <0.1 <0.1 <0.1 -- -- -- 12
DGW-15 12/09/98 33 to 35 3 <20 <0.1 <0.1 <0.1 <0.1 -- -- -- 10
DGW-15 12/09/98 40 to 42 4 <20 <0.1 <0.1 <0.1 <0.1 -- -- -- 15
DGW-16 12/09/98 75 to 77 0 <20 <0.1 <0.1 <0.1 <0.1 -- -- -- 15
DGW-16 12/09/98 85 to 87 0 <20 <0.1 <0.1 <0.1 <0.1 -- -- -- 18
FSB-6 11/15/05 1.5 -- <1.0 0.002 0.001 0.001 0.006 <0.0005 0.005 5.67 --
FSB-6 11/15/05 4.5 -- <1.0 <0.0005 <0.001 <0.001 <0.001 <0.0005 <0.001 3.49 --
FSB-6 11/15/05 9 -- <1.0 <0.0005 <0.001 <0.001 <0.001 <0.0005 <0.001 5.08 --
FSB-7 11/15/05 1 -- <1.0 <0.0005 <0.001 <0.001 <0.001 <0.0005 <0.001 36.2 --
FSB-7 11/15/05 3 -- 3.5 <0.0005 <0.001 <0.001 <0.001 <0.0005 <0.001 51.7 --
FSB-7 11/15/05 10 -- <1.0 <0.0005 <0.001 <0.001 <0.001 <0.0005 <0.001 113 --
VP-2 11/14/05 2.5 -- -- -- -- -- -- -- -- -- --
Notes:
bgs = below ground surface
PID = photoionization detector
ppm = parts per million
MTBE = methyl tertiary butyl ether by EPA Method 8260
mg/Kg = milligrams per kilogram or approximately ppm
TPH = gasoline-range total petroleum hydrocarbons by modified EPA Method 8015 or total purgeable hydrocarbons by EPA Method 8260
BTEXN = benzene, toluene, ethylbenzene, total xylenes, and naphthalene by EPA Method 8260 or 8020
<= analyte not reported above the specified practical quantitation limit
Soil Moisture = by preparation for EPA Method 8260
>= compounds present above calibration range
--= not measured/not analyzed
bold = exceeds UDEQ Initial Screening Level
Initial Screening Level
Tier 1 Screening Criteria
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700
10,000 300 3,000 4,000 10,000 700
AGW-1 11/11/94 Plume 200.00 30.16 0.00 169.84 463,000 57,000 69,100 3,110 21,100 ---- -- -- --
AGW-1 08/16/95 Plume 200.00 31.47 0.00 168.53 386,000 46,900 61,800 2,820 18,100 ---- -- -- --
AGW-1 12/09/95 Plume 200.00 38.20 0.00 161.80 372,000 50,100 63,000 2,760 18,600 ---- -- -- --
AGW-1 02/15/96 Plume 200.00 41.50 0.00 158.50 ------ -- -- ---- -- -- --
AGW-1 05/09/96 Plume 200.00 39.71 0.00 160.29 396,000 60,200 77,100 4,140 26,700 ---- -- -- --
AGW-1 09/04/98 Plume 200.00 33.70 0.00 166.30 160,000 54,000E 76,000E 3,800 26,000 <1,000 -- -- -- --
AGW-1 12/11/98 Plume 200.00 39.89 0.00 160.11 ------ -- -- ---- -- -- --
AGW-1 02/04/99 Plume 200.00 42.17 0.00 157.83 140,000 57,000E 39,000E 3,100 19,000 <400 -- -- -- --
AGW-1 05/05/99 Plume 200.00 44.57 0.47 155.78 ------ -- -- ---- -- -- --
AGW-1 08/02/99 Plume 200.00 37.51 0.00 162.49 250,000 35,000E 15,000E 3,100 14,000 430 -- -- -- --
AGW-1 11/03/99 Plume 200.00 32.73 0.00 167.27 14,000 38,000E 58,000E 3,100E 18,000E 300 -- -- -- --
AGW-1 02/02/00 Plume 200.00 39.83 Sheen 160.17 200,000 57,000 84,000 4,000 31,000 680 -- -- -- --
AGW-1 05/02/00 Plume 200.00 40.65 0.00 159.35 260,000 50,000E 80,000E 4,900 32,000 <400 -- -- -- --
AGW-1 08/02/00 Plume 200.00 35.55 0.00 164.45 150,000 30,000E 43,000E 4,200 25,000 410 -- -- -- --
AGW-1 11/13/00 Plume 200.00 35.30 0.00 164.70 160,000 16,000 49,000 2,800 25,000 1,400 -- -- -- --
AGW-1 02/21/01 Plume 200.00 40.56 0.00 159.44 100,000 24,000E 36,000E 2,700 22,000 330 -- -- -- --
AGW-1 05/30/01 Plume 200.00 26.78 Sheen 173.22 91,000 [79,000] 630 [690] 12,000 [8,000] 1,500 [1,500] 14,900 [14,900]<500 [1200]-- -- -- --
AGW-1 05/30/01 Plume 200.00 -- -- --79,000 690 8,000 1,500 14,900 1,200 -- -- -- --
AGW-1 05/30/01 Plume 200.00 -- -- --41,000 660 11,000 1,500 15,000 540 -- -- -- --
AGW-1 08/23/01 Plume 200.00 30.01 Sheen 169.99 51,000 <100 4,777 1,200 12,000 950 -- -- -- --
AGW-1 12/12/01 Plume 200.00 29.28 0.00 170.72 40,000 <100 2,860 1,210 20,160 1,110 -- -- -- --
AGW-1 12/12/01 Plume 200.00 -- -- --50,000 44 2,540 1,200 13,180 1,230 -- -- -- --
AGW-1 12/12/01 Plume 200.00 -- -- --27,000 56 4,500 1,600 17,000 840 -- -- -- --
AGW-1 02/21/02 Plume 200.00 38.22 0.00 161.78 120,000 [160,000] 2,260 [598] 8740 [12,100] 2,480 [1,440] 17,380 [10,530] 992 [1,630]-- -- -- --
AGW-1 05/15/02 Plume 200.00 25.80 0.00 174.20 38,000 [38,000] 30 [29] 1,600 [1,500]570 [550] 8,700 [9,100] 370 [380] -- -- -- --
AGW-1 09/05/02 Plume 200.00 34.55 0.00 165.45 150,000 [140,000] 3,900 [3,800] 27,000 [29,000] 3,800 [3,500] 21,000 [28,000] 760 [710]-- -- -- --
AGW-1 11/21/02 Plume 200.00 38.79 0.00 161.21 97,000 [120,000] 3,100 [3,600] 20,000 [24,000] 1,800 [1,900] 19,000 [16,000]330 [500] -- -- -- --
AGW-1 02/11/03 Plume 200.00 42.47 0.00 157.53 130,000 6,300 24,000 2,700 26,000 700 -- -- -- --
AGW-1 04/15/03 Plume 200.00 44.82 0.36 155.45 ------ -- -- ---- -- -- --
AGW-1 05/21/03 Plume 200.00 43.86 0.37 156.42 ------ -- -- ---- -- -- --
AGW-1 06/25/03 Plume 200.00 42.78 0.24 157.40 ------ -- -- ---- -- -- --
AGW-1 08/06/03 Plume 200.00 41.26 0.00 158.74 110,000 [71,000] 2,900 [4,500] 9,200 [20,000] 1,500 [2,200]9,600 [17,000]530 [410] -- -- -- --
AGW-1 11/18/03 Plume 200.00 38.65 0.00 161.35 28,000 [30,000] 1,100 [960] 3,400 [3,000]680 [590]4,100 [3,600]220 [220] -- -- -- --
AGW-1 02/19/04 Plume 200.00 43.59 0.04 156.44 55,000 3,600 9,300 1,900 11,000 390 -- -- -- --
AGW-1 03/10/04 Plume 200.00 44.41 0.06 155.64 ------ -- -- ---- -- -- --
AGW-1 04/12/04 Plume 200.00 45.39 0.13 154.71 ------ -- -- ---- -- -- --
AGW-1 05/11/04 Plume 200.00 44.17 0.01 155.84 35,000 [30,000] 1,400 [1,300] 2,000 [1,900] 1,300 [1,200]6,900 [6,400] 390 [350] -- -- -- --
AGW-1 08/16/04 Plume 200.00 38.85 0.00 161.15 47,000 [59,000] 1,300 [1,300] 4,300 [4,900] 1,600 [1,700]9,500 [11,000]490 [490] -- -- -- --
AGW-1 11/10/04 Plume 200.00 40.40 0.00 159.60 24,000 [22,000] 930 [620]1,000 [380]970 [650]3,000 [1,300] 320 [230] -- -- -- --
AGW-1 02/02/05 Plume 200.00 44.44 0.00 155.56 21,000 [24,000] 1,000 [1,200]750 [760]970 [1,100]2,600 [2,800] 310 [320] -- -- -- --
AGW-1 03/28/05 Plume 200.00 46.29 0.02 153.73 ------ -- -- ---- -- -- --
AGW-1 05/09/05 Plume 200.00 46.58 0.02 153.44 46,000 [46,000] 1,300 [1,400] 4,900 [3,900] 1,500 [1,600]8,900 [7,200] 520 [520] -- -- -- --
AGW-1 08/16/05 Plume 200.00 37.51 0.00 162.49 35,000 [32,000] 1,100 [1,100] 3,400 [3,400] 960 [990]5,400 [5,500] 300 [280] -- -- -- --
AGW-1 11/16/05 Plume 200.00 30.95 0.00 169.05 14,000 [16,000] 46 [19]170 [66] 86 [40] 900 [420] 310 [310] -- -- -- --
AGW-1 02/21/06 Plume 200.00 40.84 0.00 159.16 24,000 [23,000] 1,000 [950]260 [250] 590 [580] 2,200 [2,100] 270 [260] -- -- -- --
AGW-1 05/09/06 Plume 200.00 42.08 0.00 157.92 20,000 [20,000] 950 [890]110 [130] 590 [670] 1,800 [2,000] 260 [250] -- -- -- --
AGW-1 02/15/07 Plume 200.00 44.07 0.00 155.93 15,000 [14,000] 320 [310]19 [18] 490 [460] 820 [750] 210 [210] -- -- -- --
AGW-1 07/09/07 Plume 200.00 44.93 0.00 155.07 11,000 400 9 510 630 150 -- -- -- --
AGW-1 02/27/08 Plume 200.00 44.99 0.00 155.01 14,000 [15,000] 770 [890]130 [120]690 [820]1,400 [1,600] 190 [230] -- -- -- --
AGW-1 07/08/08 Plume 200.00 42.79 0.00 157.21 9,000 [9,600] 630 [600]180 [160]640 [540]2,300 [1,400] 150 [140] -- -- -- --
AGW-1 02/10/09 Plume 200.00 45.09 0.00 154.91 15,000 [16,000] 700 [670]85 [66]670 [630]1,400 [1,100] 210 [180] -- -- -- --
AGW-1 08/03/09 Plume 200.00 38.71 0.00 161.29 19,000 [21,000] 600 [550]96 [110]860 [810]2,200 [2,000] 170 [190] -- -- -- --
AGW-1 03/01/10 Plume 200.00 46.15 0.00 153.85 17,000 [20,00] 690 [700]68 [59]910 [900]1,600 [1,400] 140 [120] -- -- -- --
AGW-1 08/02/10 Plume 200.00 39.98 Sheen 160.02 24,000 [26,000] 1,100 [990]92 [92]1,300 [1,200]2,900 [2,600] 220 [220] -- -- -- --
AGW-1 02/10/11 Plume 200.00 41.3 0.00 158.7 20,000 [24,000] 320 [490]28 [35] 440 [440] 1,200 [2,200] 160 [190] -- -- -- --
AGW-1 8/18/2011 Plume 200.00 35.85 Sheen 164.15 23,000 570 23 660 1,900 150 <250 278,000 56.6 --
AGW-1 03/08/12 Plume 200.00 44.64 0.00 155.36 14,000 [14,000] 570 [570]10 [12] 640 [630] 640 [660] 56 [58] 720 [<250] 78,800 [67,800] 243 [52.2] --
AGW-1 8/28/2012 Plume 200.00 38.11 Sheen 161.89 13,000 400 16 820 1,300 68 610 222,000 248.0 2.8
Initial Screening Levels
Wells Sampled Annually
Tier 1 Screening Criteria
211535_Tables Page 1 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
AGW-1 3/28/2013 Plume 200.00 44.67 Sheen 155.33 12,000 480 16 860 560 45 <250 50,400 2,440 3.42
AGW-1 8/21/2013 Plume 200.00 37.58 Sheen 162.42 18,000 [14,000] 570 [530] 41 [34] 1,100 [930]2,200 [1,800] 100 [83] <250 [<250] 110,000 [121,000] 128 [72.6] 2.06
AGW-1 3/19/2014 Plume 200.00 43.68 Sheen 156.32 14,000 380 13 610 670 37 <250 23,700 73.4 5.20
AGW-1 9/23/2014 Plume 200.00 34.98 0.00 165.02 17,000 170 22 540 1,100 53 <250 475,000 1,340 3.58
AGW-1 3/26/2015 Plume 200.00 44.89 Sheen 155.11 6,700 100 3 230 350 14 <250 428,000 259 2.49
AGW-1 9/24/2015 Plume 200.00 35.75 Sheen 164.25 15,000 160 6 400 750 35 <250 583,000 97.4 1.71
AGW-1 9/29/2016 Plume 200.00 37.77 Sheen 162.23 9,600 190 3 440 240 10 <250 159,000 <74.7 2.20
AGW-1 8/30/2017 Plume 200.00 39.55 Sheen 160.45 8,700 140 3 390 170 7 <250 153,000 156.0 4.05
AGW-1 11/7/2018 Plume 200.00 34.90 0.00 165.10 840 3 0.2 1 12 <4 6,500 701,000 <40.0 J 3.03
AGW-1 9/12/2019 Plume 200.00 35.06 0.00 164.94 4,900 140 4 J 240 37 J <10 <250 303,000 220* 1.28
AGW-1 9/29/2020 Plume 200.00 40.91 0.00 159.09 1840 [1,870] 133 [98.2]4.26 [4.11] 161 [168] 34.3 [29.4] 6.01 [5.85] <48.0 [<48.0] 521,000 [512,000] 5,960* [6,480*] 0.9 [0.9]
AGW-1 10/26/2021 Plume 200.00 41.93 0.00 158.07 1,800 83.4 2.04 128 14.9 4.54 J J 3 <48 107,000 6,280* 2.85
AGW-1 9/28/2022 Plume 200.00 -- -- --
AGW-1 11/8/2023 Plume 200.00 41.32 -- --805 78.9 2.53 J 60.4 3.78 J <5.00 59.0 J**620,000 7900*0.88
CGW-11 10/02/98 Plume 198.08 69.26 0.00 128.82 12,000E 1,100E 1,900E 180E 3,400E 110E --------
CGW-11 12/11/98 Plume 198.08 73.61 0.00 124.47 --------------------
CGW-11 02/05/99 Plume 198.08 74.26 0.00 123.82 9,900 2,100E 2,100E 190 2,100 <100 --------
CGW-11 05/05/99 Plume 198.08 --------------------------
CGW-11 08/02/99 Plume 198.08 --------------------------
CGW-11 11/02/99 Plume 198.08 67.79 0.00 130.29 5,500 390E 470E 250E 1,400E 66 --------
CGW-11 02/02/00 Plume 198.08 71.00 0.00 127.08 --------------------
CGW-11 05/02/00 Plume 198.08 72.17 0.00 125.91 --------------------
CGW-11 08/02/00 Plume 198.08 69.60 0.00 128.48 --------------------
CGW-11 11/13/00 Plume 198.08 69.13 0.00 128.95 --------------------
CGW-11 02/21/01 Plume 198.08 71.41 0.00 126.67 --------------------
CGW-11 05/30/01 Plume 198.08 65.97 0.00 132.11 --------------------
CGW-11 08/23/01 Plume 198.08 66.70 0.00 131.38 --------------------
CGW-11 12/12/01 Plume 198.08 61.50 0.00 136.58 --------------------
CGW-11 02/21/02 Plume 198.08 69.19 0.00 128.89 --------------------
CGW-11 05/15/02 Plume 198.08 66.02 0.00 132.06 --------------------
CGW-11 09/05/02 Plume 198.08 68.44 0.00 129.64 23,000 4,200 98 72 1,000 110 --------
CGW-11 11/21/02 Plume 198.08 70.38 0.00 127.70 16,000 3,600 92 120 1,000 100 --------
CGW-11 02/11/03 Plume 198.08 71.50 0.00 126.58 15,000 3,700 64 69 860 92 --------
CGW-11 05/21/03 Plume 198.08 71.86 0.00 126.22 5,500 1,500 23 29 360 50 --------
CGW-11 08/06/03 Plume 198.08 69.19 0.00 128.89 14,000 3,700 50 63 800 120 --------
CGW-11 11/18/03 Plume 198.08 68.78 0.00 129.30 14,000 3,100 42 60 690 120 --------
CGW-11 02/18/04 Plume 198.08 69.08 0.00 129.00 13,000 2,800 28 55 460 83 --------
CGW-11 05/11/04 Plume 198.08 70.01 0.00 128.07 12,000 3,400 26 49 420 79 --------
CGW-11 08/16/04 Plume 198.08 69.24 0.00 128.84 8,700 2,200 13 43 180 57 --------
CGW-11 11/11/04 Plume 198.08 68.65 0.00 129.43 12,000 3,800 <28 49 340 110 --------
CGW-11 02/02/05 Plume 198.08 69.13 0.00 128.95 9,900 3,500 11 40 230 91 --------
CGW-11 05/09/05 Plume 198.08 70.18 0.00 127.90 8,800 4,000 5 38 170 99 --------
CGW-11 08/16/05 Plume 198.08 68.78 0.00 129.30 6,900 2,400 3 34 23 59 --------
CGW-11 11/15/05 Plume 198.08 64.70 0.00 133.38 7,500 1,100 510 45 570 44 --------
CGW-11 02/21/06 Plume 198.08 67.73 0.00 130.35 7,200 3,000 7 19 5 9 --------
CGW-11 05/09/06 Plume 198.08 68.92 0.00 129.16 17,000 3,100 2 30 2 13 --------
CGW-11 02/15/07 Plume 198.08 69.25 0.00 128.83 6,900 2,300 <3 21 <3 <5 --------
CGW-11 07/09/07 Plume 198.08 70.07 0.00 128.01 5,700 2,600 <3 15 3 <5 --------
CGW-11 02/27/08 Plume 198.08 69.04 0.00 129.04 5,200 2,200 <3 12 <3 <5 --------
CGW-11 07/08/08 Plume 198.08 69.06 0.01 129.03 3,900 2,200 <2 10 <2 <4 --------
CGW-11 02/10/09 Plume 198.08 68.76 0.00 129.32 4,800 1,400 <1 8 1 <2 --------
CGW-11 08/03/09 Plume 198.08 68.82 0.00 129.26 4,000 1,100 1 5 1 <1 --------
CGW-11 03/01/10 Plume 198.08 68.24 0.00 129.84 4,200 810 <0.5 4 <0.5 <1 --------
CGW-11 08/02/10 Plume 198.08 68.84 0.02 129.26 3,200 740 0.5 3 <0.5 <1 --------
CGW-11 02/10/11 Plume 198.08 67.70 0.00 130.38 3,500 790 0.6 3 <0.50 <1 --------
CGW-11 08/18/11 Plume 198.08 67.72 0.00 130.36 2,400 400 19 4 14 1 <250 1,450,000 331 --
CGW-11 03/08/12 Plume 198.08 68.57 0.00 129.51 1,600 160 <0.5 1 <0.5 <1 <250 1,260,000 209 --
CGW-11 08/28/12 Plume 198.08 68.04 0.00 130.04 1,400 150 <0.5 2 <0.5 <1 710 1,410,000 103 2.74
CGW-11 3/28/2013 Plume Fringe 198.08 69.05 0.00 129.03 850 35 <0.5 0.8 <0.5 <1 <250 1,320,000 447 --
CGW-11 8/21/2013 Plume Fringe 198.08 68.76 0.00 129.32 760 40 <0.5 <0.5 <0.5 <1 <250 1,380,000 <43.0 2.38
CGW-11 3/19/2014 Plume Fringe 198.08 68.84 0.00 129.24 640 5 <0.5 1 <0.5 <1 <250 1,340,000 <43.0 2.38
CGW-11 9/23/2014 Plume Fringe 198.08 67.56 0.00 130.52 440 22 3 4 13 1 <250 1,210,000 92.9 2.76
CGW-11 3/26/2015 Plume Fringe 198.08 68.81 0.00 129.27 240 3 <0.5 <0.5 <0.5 <1 <250 1,230,000 <33.4 3.58
CGW-11 9/24/2015 Plume Fringe 198.08 67.88 0.00 130.20 670 9 0.6 2 3 <1 <250 1,360,000 <33.3 3.58
CGW-11 9/29/2016 Plume Fringe 198.08 67.41 0.00 130.67 810 58 4 8 35 4 <250 1,130,000 <74.7 3.43
Well not sampled due to no access
211535_Tables Page 2 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
CGW-11 8/30/2017 Sentinel 198.08 69.69 0.00 128.39 170 0.6 <0.5 <0.5 <0.5 <1 <250 1,570,000 295.0 3.38
CGW-11 11/7/2018 Sentinel 198.08 67.74 0.00 130.34 380 2 <0.2 0.3 <0.5 <4 360 1,030,000 <40.0 J 3.28
CGW-11 9/12/2019 Sentinel 198.08 68.22 0.00 129.86 330 [280] 1 [0.9 J] <0.2 [<0.2] <0.4 [<0.4] <1 [<1] <1 [<1]<250 [<250] 1,510,000 [1,460,000] 85,300* [83,100*] 0.85 [0.85]
CGW-11 9/29/2020 Sentinel 198.08 68.58 0.00 129.50 167 UB
0.881 <0.278 <0.137 <0.174 <1.00 100 UB 1,570,000 816* 0.11
CGW-11 10/26/2021 Sentinel 198.08 69.40 0.00 128.68 172 B [180 B] 0.566 J [0.599 J] <0.278 [<0.278] <0.137 [<0.137] <0.174 [<0.174] <1.0 J3 [<1.0 J3] <480 J5 [<480 T8] 1,310,000 [1,390,000] 6,010* [12,600*] 2.24
CGW-11 9/28/2022 Sentinel 198.08 69.84 0.00 128.24 156 B 0.650 J <0.278 <0.137 <0.174 <1.0 J3 <50.0**1,480,000 6,820*2.82
CGW-11 11/8/2023 Sentinel 198.08 69.83 0.00 128.25 39.4 J 0.380 J <0.278 <0.137 <0.174 <1.00 <50.0**1,340,000 800*2.78
CGW-12 10/02/98 Plume 197.00 47.12 0.00 149.88 18,000E 1,300E 2,100E 1,200E 3,700E 430E --------
CGW-12 12/11/98 Plume 197.00 52.34 0.00 144.66 --------------------
CGW-12 02/05/99 Plume 197.00 56.18 0.00 140.82 38,000 3,700 11,000E 950 7,000 210 --------
CGW-12 05/05/99 Plume 197.00 60.98 0.00 136.02 21,000 890E 1,600E 800E 3,600E 220 --------
CGW-12 08/02/99 Plume 197.00 57.10 0.00 139.90 30,000 1,200E 400E 84 630E 46 --------
CGW-12 11/02/99 Plume 197.00 44.12 0.00 152.88 29,000 5,200E 11,000E 1,100 9,200 250 --------
CGW-12 02/02/00 Plume 197.00 52.21 0.00 144.79 52,000 7,200 17,000 1,500 14,000 <400 --------
CGW-12 05/02/00 Plume 197.00 57.82 0.00 139.18 60,000 7,100E 16,000E 2,100 14,000E 250 --------
CGW-12 08/02/00 Plume 197.00 48.85 0.00 148.15 14,000 2,000E 1,800E 690E 3,000E 210 --------
CGW-12 11/13/00 Plume 197.00 45.60 0.00 151.40 36,000 3,200 6,600 1,400 13,000 410 --------
CGW-12 02/21/01 Plume 197.00 53.04 0.00 143.96 38,000 3,000E 3,400E 2,000E 7,900E 360 --------
CGW-12 05/30/01 Plume 197.00 41.15 0.00 155.85 46,000 2,300 2,800 780 6,220 <250 --------
CGW-12 08/22/01 Plume 197.00 41.25 0.00 155.75 30,000 1,400 2,800 610 6,500 <500 --------
CGW-12 12/12/01 Plume 197.00 36.21 0.00 160.79 11,000 424 53 185 854 172 --------
CGW-12 02/21/02 Plume 197.00 48.78 0.00 148.22 31,000 811 297 418 1,360 227 --------
CGW-12 05/15/02 Plume 197.00 37.78 0.00 159.22 23,000 750 300 600 2,600 230 --------
CGW-12 09/05/02 Plume 197.00 44.56 0.00 152.44 28,000 530 66 860 2,900 210 --------
CGW-12 11/21/02 Plume 197.00 49.26 0.00 147.74 60,000 1,700 7,700 1,900 10,000 320 --------
CGW-12 02/11/03 Plume 197.00 55.51 0.16 141.61 --------------------
CGW-12 04/15/03 Plume 197.00 58.31 0.28 138.90 --------------------
CGW-12 05/21/03 Plume 197.00 59.22 0.32 138.02 --------------------
CGW-12 06/17/03 Plume 197.00 57.60 0.00 139.40 --------------------
CGW-12 08/06/03 Plume 197.00 58.98 0.00 138.02 61,000 2,000 4,600 1,800 11,000 430 --------
CGW-12 11/18/03 Plume 197.00 55.87 0.00 141.13 65,000 1,800 3,300 1,700 7,900 420 --------
CGW-12 02/18/04 Plume 197.00 59.29 0.04 137.74 48,000 1,500 3,500 1,600 7,600 300 --------
CGW-12 03/10/04 Plume 197.00 60.38 0.10 136.70 --------------------
CGW-12 04/12/04 Plume 197.00 63.09 1.88 135.32 --------------------
CGW-12 05/11/04 Plume 197.00 63.94 1.93 134.51 --------------------
CGW-12 06/15/04 Plume 197.00 63.08 1.13 134.77 --------------------
CGW-12 07/12/04 Plume 197.00 62.05 0.92 135.64 --------------------
CGW-12 08/16/04 Plume 197.00 59.88 0.48 137.48 --------------------
CGW-12 09/08/04 Plume 197.00 57.94 0.04 139.09 --------------------
CGW-12 11/11/04 Plume 197.00 55.63 0.05 141.41 82,000 2,500 11,000 2,300 16,000 410 --------
CGW-12 12/14/04 Plume 197.00 57.09 0.14 140.02 --------------------
CGW-12 01/25/05 Plume 197.00 59.78 0.13 137.32 --------------------
CGW-12 02/02/05 Plume 197.00 60.28 0.26 136.92 69,000 2,200 8,300 2,500 14,000 540 --------
CGW-12 03/17/05 Plume 197.00 63.20 1.31 134.78 --------------------
CGW-12 05/09/05 Plume 197.00 63.15 0.22 134.02 --------------------
CGW-12 06/07/05 Plume 197.00 63.12 0.10 133.96 --------------------
CGW-12 07/18/05 Plume 197.00 61.46 0.00 135.54 --------------------
CGW-12 08/16/05 Plume 197.00 57.60 0.00 139.40 59,000 2,300 5,000 1,900 11,000 500 --------
CGW-12 10/28/05 Plume 197.00 50.82 0.08 146.24 --------------------
CGW-12 11/17/05 Plume 197.00 44.84 0.01 152.17 120,000 600 1,200 1,800 9,600 590 --------
CGW-12 01/26/06 Plume 197.00 50.31 0.00 146.69 --------------------
CGW-12 02/21/06 Plume 197.00 52.50 0.00 144.50 49,000 1,100 670 1,300 5,500 330 --------
CGW-12 04/06/06 Plume 197.00 55.90 Sheen 141.10 --------------------
CGW-12 05/09/06 Plume 197.00 57.57 Sheen 139.43 17,000 1,300 530 1,300 5,100 270 --------
CGW-12 02/15/07 Plume 197.00 59.10 0.07 137.95 44,000 1,400 410 1,700 6,500 360 --------
CGW-12 07/09/07 Plume 197.00 61.00 0.00 136.00 39,000 2,000 940 2,100 6,700 340 --------
CGW-12 02/27/08 Plume 197.00 59.01 0.00 137.99 41,000 1,400 810 2,000 9,100 300 --------
CGW-12 07/08/08 Plume 197.00 59.58 0.03 137.44 32,000 1,700 530 2,100 5,300 380 --------
CGW-12 02/10/09 Plume 197.00 57.85 0.00 139.15 44,000 1,700 470 1,800 6,200 350 --------
CGW-12 08/03/09 Plume 197.00 56.17 0.00 140.83 45,000 2,000 370 2,200 5,900 240 --------
CGW-12 03/01/10 Plume 197.00 58.59 0.10 138.49 --------------------
CGW-12 08/01/10 Plume 197.00 55.84 0.22 141.33 --------------------
CGW-12 02/10/11 Plume 197.00 52.77 0.02 144.25 --------------------
CGW-12 08/18/11 Plume 197.00 47.41 0.03 149.61 --------------------
CGW-12 03/08/12 Plume 197.00 56.78 Sheen 140.22 41,000 700 91 1,200 2,500 160 <250 1,310,000 356 --
CGW-12 08/28/12 Plume 197.00 50.82 Sheen 146.18 26,000 [27,000]630 [650]64 [66]1,300 [1,300]2,100 [2,100]170 [180]<250 [430]1,340,000 [1,240,000]220 [290]1.54
211535_Tables Page 3 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
CGW-12 3/28/2013 Plume 197.00 58.23 Sheen 138.77 59,000 [59,000]2,100 [1,900]430 [370]2,600 [3,600]9,200 [8,300]490 [590]<250 [<250]1,300,000 [1,350,000]887 [1,100]3.05
CGW-12 8/21/2013 Plume 197.00 53.62 0.07 143.43 --------------------
CGW-12 3/19/2014 Plume 197.00 56.40 Sheen 140.60 76,000 340 49 1,400 2,600 170 <250 1,200,000 628 1.82
CGW-12 9/23/2014 Plume 197.00 45.24 0.03 151.78 --------------------
CGW-12 3/26/2015 Plume 197.00 57.46 Sheen 139.54 38,000 1,700 300 2,400 8,900 320 <250 1,430,000 66.3 4.60
CGW-12 9/23/2015 Plume 197.00 46.88 0.01 150.13 --------------------
CGW-12 9/29/2016 Plume 197.00 50.99 Sheen 146.01 15,000 77 14 410 690 33 <250 1,210,000 255 2.17
CGW-12 8/30/2017 Plume 197.00 54.20 Sheen 142.80 14,000 630 81 820 1,400 86 <250 1,500,000 417 2.78
CGW-12 11/8/2018 Plume 197.00 45.41 0.00 151.59 3,500 8 0.3 38 <0.5 <4 <250 969,000 <40.0 J 2.36
CGW-12 9/12/2019 Plume 197.00 45.27 0.00 151.73 7,100 99 6.0 160 97 <5 <250 1,390,000 343* 1.91
CGW-12 9/29/2020 Plume 197.00 54.26 0.00 142.74 8,670 116 <13.9 247 248 <50.0 <48.0 1,580,000 291* 0.07
CGW-12 10/26/2021 Plume 197.00 55.74 0.00 141.26 10,300 76.7 <13.9 206 230 <50 J3 <480 1,520,000 2,000* 5.62
CGW-12 9/28/2022 Plume 197.00 53.72 0.00 143.28 4,850 [5,190]58 [57.6]<13.9 [3.98]172 [246]38.6 J [64.8]<50 [2.04 J]<250** [<250**]1,440,000 [1,500,000]450* [556*]
10.00
CGW-12 11/8/2023 Plume 197.00 54.42 0.00 142.58 11,100 [12,300]91.8 [97.5]5.87 [<6.95]266 [229]72.8 [61.6 J]<5.00 [<25.0]<100** [<100**]1,350,000 [1,330,000]1,430* [1,550*]
0.41
DGW-16 12/18/98 Plume 193.84 80.34 0.00 113.50 <20 620E 32 <2 1,000E ----------
DGW-16 02/05/99 Plume 193.84 82.75 0.00 111.09 930 330E 8.6 <2 220 6.4 --------
DGW-16 05/05/99 Plume 193.84 83.86 0.00 109.98 <20 <1 <2 <2 370 5.9 --------
DGW-16 08/02/99 Plume 193.84 84.50 0.00 109.34 2,100 240E 2.2 <2 110 <4 --------
DGW-16 11/04/99 Plume 193.84 79.39 0.00 114.45 700 300E 23 12 290E 16 --------
DGW-16 02/02/00 Plume 193.84 82.60 0.00 111.24 1,900 990 16 <2 510 20 --------
DGW-16 05/02/00 Plume 193.84 84.31 0.00 109.53 8,100 2,400 64 <20 1,200 51 --------
DGW-16 08/03/00 Plume 193.84 82.25 0.00 111.59 760 380E 5.8 <20 120 49 --------
DGW-16 11/13/00 Plume 193.84 80.05 0.00 113.79 1,600 620E 7.6 <20 180 28 --------
DGW-16 02/21/01 Plume 193.84 83.66 0.00 110.18 3,000 680E 2.8 <20 260 5 --------
DGW-16 05/30/01 Plume 193.84 87.78 0.00 106.06 <100 11 <5 <5 <5 <5 --------
DGW-16 08/22/01 Plume 193.84 76.91 0.00 116.93 400 120 <5 <5 <5 <5 --------
DGW-16 12/12/01 Plume 193.84 69.95 0.00 123.89 <100 [25]<5 [5]<5 [<2]<5 [<2]<5 [<2]5.76 [<2]--------
DGW-16 02/21/02 Plume 193.84 80.01 0.00 113.83 1,500 339 <5 <5 <5 8 --------
DGW-16 05/15/02 Plume 193.84 80.00 0.00 113.84 1,400 380 7 <0.5 23 11 --------
DGW-16 09/05/02 Plume 193.84 79.93 0.00 113.91 650 160 0.6 <0.5 1 3 --------
DGW-16 11/21/02 Plume 193.84 81.72 0.00 112.12 4,000 1,200 6 2 74 30 --------
DGW-16 02/11/03 Plume 193.84 83.55 0.00 110.29 8,900 2,300 10 4 110 72 --------
DGW-16 05/21/03 Plume 193.84 84.69 0.00 109.15 3,600 970 3 1 35 31 --------
DGW-16 08/06/03 Plume 193.84 84.82 0.00 109.02 8,000 1,700 8 3 83 80 --------
DGW-16 11/18/03 Plume 193.84 83.68 0.00 110.16 7,800 1,800 8 3 90 74 --------
DGW-16 02/18/04 Plume 193.84 84.14 0.00 109.70 6,700 1,900 7 3 62 58 --------
DGW-16 05/11/04 Plume 193.84 85.30 0.00 108.54 7,900 2,200 8 3 60 56 --------
DGW-16 08/16/04 Plume 193.84 84.92 0.00 108.92 7,000 1,600 4 2 34 57 --------
DGW-16 11/11/04 Plume 193.84 83.24 0.00 110.60 2,100 710 1 1 14 24 --------
DGW-16 02/02/05 Plume 193.84 84.23 0.00 109.61 5,900 1,900 2 2 25 54 --------
DGW-16 05/09/05 Plume 193.84 85.57 0.00 108.27 6,800 2,600 3 2 29 36 --------
DGW-16 08/16/05 Plume 193.84 83.40 0.00 110.44 4,300 1,100 2 1 16 9 --------
DGW-16 11/16/05 Plume 193.84 80.32 0.00 113.52 250 76 <0.5 <0.5 1 <1.0 --------
DGW-16 02/21/06 Plume 193.84 82.97 0.00 110.87 1,900 610 1 <0.6 6 3 --------
DGW-16 05/09/06 Plume 193.84 83.72 0.00 110.12 7,100 2,200 3 2 9 8 --------
DGW-16 02/15/07 Plume 193.84 --------------------------
DGW-16 07/09/07 Plume 193.84 85.42 0.00 108.42 6,900 1,900 4 <1 8 4 --------
DGW-16 02/27/08 Plume 193.84 84.50 0.00 109.34 3,900 1,400 3 <2 4 <4 --------
DGW-16 07/08/08 Plume 193.84 85.24 0.00 108.60 5,000 1,400 4 1 4 4 --------
DGW-16 02/10/09 Plume 193.84 84.36 0.00 109.48 6,500 1,500 3 1 4 5 --------
DGW-16 08/03/09 Plume 193.84 83.86 0.00 109.98 6,700 1,700 4 2 5 4 --------
DGW-16 03/01/10 Plume 193.84 83.62 0.00 110.22 4,600 1,100 3 <1 2 2 --------
DGW-16 08/02/10 Plume 193.84 84.94 0.00 108.90 5,600 1,800 4 0.8 2 2 --------
DGW-16 02/10/11 Plume 193.84 83.34 0.00 110.50 4,000 980 2 <0.5 0.8 1 --------
DGW-16 08/18/11 Plume 193.84 83.40 0.00 110.44 2,700 770 2 <0.5 1 <1 1,200 1,390,000 <14.1 --
DGW-16 03/08/12 Plume 193.84 84.41 0.00 109.43 3,400 1,100 <5 <5 9 <10 360 1,260,000 <14.1 --
DGW-16 08/28/12 Plume 193.84 83.51 0.00 110.33 3,200 810 <5 <5 <5 <10 2,800 1,290,000 <33.3 3.53
DGW-16 3/28/2013 Plume 193.84 84.95 0.00 108.89 3,200 650 2 <0.5 1 1 <250 1,370,000 <33.3 3.25
DGW-16 8/21/2013 Plume 193.84 84.54 0.00 109.30 2,400 320 2 <0.5 2 <1 <250 1,380,000 <43.0 1.96
DGW-16 3/19/2014 Plume 193.84 84.30 0.00 109.54 1,800 120 <3 <3 <3 <5 <250 1,360,000 <43.0 2.03
DGW-16 9/23/2014 Plume Fringe 193.84 83.34 0.00 110.50 680 23 <0.5 <0.5 <0.5 <1 450 1,070,000 <33.4 3.44
DGW-16 3/26/2015 Plume Fringe 193.84 84.46 0.00 109.38 710 42 0.6 <0.5 <0.5 <1 <250 1,300,000 <33.4 4.45
DGW-16 9/24/2015 Plume Fringe 193.84 83.21 0.00 110.63 270 13 <0.5 <0.5 <0.5 <1 1,500 1,060,000 <33.3 5.54
DGW-16 9/29/2016 Plume Fringe 193.84 83.27 0.00 110.57 170 1 <0.5 <0.5 <0.5 <1 5,100 1,210,000 <74.7 3.02
DGW-16 8/30/2017 Plume Fringe 193.84 85.09 0.00 108.75 440 4 <0.5 <0.5 <0.5 <1 <250 1,480,000 <80.5 3.35
211535_Tables Page 4 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
DGW-16 11/7/2018 Sentinel 193.84 83.40 0.00 110.44 170 1 <0.2 <0.2 <0.5 <1 980 892,000 <40.0 J 3.01
DGW-16 9/12/2019 Sentinel 193.84 82.98 0.00 110.86 88 0.7 <0.2 <0.4 <1 <1 <250 1,420,000 2,250* 2.65
DGW-16 9/29/2020 Sentinel 193.84 83.50 0.00 110.34 100 UB
<0.0941 <0.278 <0.137 <0.174 <1.00 12,600 1,440,000 38.7* 0.18
DGW-16 10/26/2021 Sentinel 193.84 85.22 0.00 108.62 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.0 J3 <480 1,320,000 6,560* 4.49
DGW-16 9/28/2022 Sentinel 193.84 85.45 0.00 108.39 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.0 <50.0**1,410,000 16,000*2.75
DGW-16 11/8/2023 Sentinel 193.84 85.18 0.00 108.66 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.00 <50.0**1,320,000 352*2.62
FGW-17 09/20/05 Plume 192.34 47.80 0.00 144.54 7,000 1,000 23 130 64 75 --------
FGW-17 11/16/05 Plume 192.34 45.81 0.00 146.53 6,900 640 24 140 160 67 --------
FGW-17 02/21/06 Plume 192.34 49.82 0.00 142.52 7,100 380 20 76 42 67 --------
FGW-17 05/08/06 Plume 192.34 53.77 0.00 138.57 5,100 330 15 47 13 50 --------
FGW-17 02/15/07 Plume 192.34 54.83 0.00 137.51 4,800 200 5 25 3 5 --------
FGW-17 07/09/07 Plume 192.34 57.13 0.00 135.21 3,600 200 5 17 2 2 --------
FGW-17 02/27/08 Plume 192.34 55.09 0.00 137.25 4,200 160 4 30 2 1 --------
FGW-17 07/08/08 Plume 192.34 55.46 0.00 136.88 2,800 140 2 12 1 <1 --------
FGW-17 02/10/09 Plume 192.34 54.07 0.00 138.27 2,600 110 2 22 1 1 --------
FGW-17 08/03/09 Plume 192.34 52.93 0.00 139.41 3,800 76 1 8 <0.5 <1 --------
FGW-17 03/01/10 Plume 192.34 54.78 0.00 137.56 3,000 46 1 1 <0.5 <1 --------
FGW-17 08/02/10 Plume 192.34 52.49 0.00 139.85 2,500 38 0.8 0.9 <0.5 <1 --------
FGW-17 02/11/11 Plume 192.34 50.11 0.00 142.23 2,900 67 2 8 2 <1 --------
FGW-17 08/18/11 Plume 192.34 47.51 0.00 144.83 2,300 40 0.9 0.7 0.5 <1 <250 1,500,000 94.2 --
FGW-17 03/08/12 Plume 192.34 53.46 0.00 138.88 2,700 6 <0.5 <0.5 <0.5 <1 <250 1,450,000 147.0 --
FGW-17 08/29/12 Plume 192.34 49.10 0.00 143.24 2,100 10 <0.5 1.0 <0.5 <1 <250 1,340,000 94 2.67
FGW-17 3/28/2013 Plume 192.34 54.67 0.00 137.67 1,600 2 <0.5 <0.5 <0.5 <1 <250 1,370,000 333 1.17
FGW-17 8/21/2013 Plume 192.34 50.99 0.00 141.35 2,200 4 <0.5 <0.5 <0.5 <1 <250 1,440,000 79.6 0.51
FGW-17 3/19/2014 Plume 192.34 52.98 0.00 139.36 1,400 [1,300]1 [1]<0.5 [<0.5]<1 [<1]<0.5 [<0.5]<1 [<1]<250 [<250]1,420,000 [1,420,000]108 [107]1.71
FGW-17 9/23/2014 Plume 192.34 46.27 0.00 146.07 1,300 [1,300]5 [4]<0.5 [<0.5]<0.5 [<0.5]<0.5 [<0.5]<1 [<1]<250 [<250]1,200,000 [1,460,000]<33.4 [34.8]-- [0.43]
FGW-17 3/26/2015 Plume 192.34 53.95 0.00 138.39 1,100 [1,200]1 [1]<0.5 [<0.5]<0.5 [<0.5]<0.5 [<0.5]<1 [<1]<250 [<250]1,320,000 [1,350,000]<33.4 [<33.4]2.18
FGW-17 9/24/2015 Plume 192.34 47.89 0.00 144.45 1,700 [1,600]2 [2]<0.5 [<0.5]<0.5 [<0.5]<0.5 [<0.5]<1 [<1]<250 [<250]1,390,000 [1,330,000]<33.3 [<33.3]0.31
FGW-17 9/29/2016 Plume 192.34 49.29 0.00 143.05 2,300 [2,500]1 [1]<0.5 [<0.5]<0.5 [<0.5]<0.5 [<0.5]<1 [<1]<250 [<250]1,410,000 [1,410,000]<74.7 [<74.7]2.88
FGW-17 8/30/2017 Plume Fringe 192.34 51.65 0.00 140.69 720 [650] 0.6 [0.7] <0.5 [<0.5] <0.5 [<0.5] <0.5 [<0.5] <1 [<1] <250 [<250] 1,450,000 [1,530,000] 81.3 [<80.5] 3.36
FGW-17 11/7/2018 Plume Fringe 192.34 47.34 0.00 145.00 1,000 0.5 <0.2 0.2 <0.5 <4 <250 877,000 <40.0 J 2.91
FGW-17 9/12/2019 Plume Fringe 192.34 46.91 0.00 145.43 1,300 0.8 J <0.2 <0.4 <1 <1 <250 1,380,000 194 J * 2.66
FGW-17 9/29/2020 Plume Fringe 192.34 51.69 0.00 140.65 880 0.435 <0.278 <0.137 <0.174 <1.00 <48.0 1,660,000 222* 0.10
FGW-17 10/26/2021 Plume Fringe 192.34 51.95 0.00 140.39 1,010 0.670 J <0.278 <0.137 <0.174 <1.0 J3 <480 1,260,000 1,070* 1.14
FGW-17 9/28/2022 Plume Fringe 192.34 51.35 0.00 140.99 665 0.398 J <0.278 0.336 J <0.174 <1.0 <50.0**1,510,000 336*1.34
FGW-17 11/8/2023 Plume Fringe 192.34 52.04 0.00 140.30 834 0.530 J <0.278 <0.137 <0.174 <1.00 <50.0**1,330,000 498*0.90
FGW-20 09/23/05 Sentinel 175.26 130.00 0.00 45.26 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 11/17/05 Sentinel 175.26 100.40 0.00 74.86 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 02/21/06 Sentinel 175.26 99.03 0.00 76.23 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 05/08/06 Sentinel 175.26 102.09 0.00 73.17 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 02/15/07 Sentinel 175.26 103.00 0.00 72.26 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 07/09/07 Sentinel 175.26 107.20 0.00 68.06 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 02/27/08 Sentinel 175.26 103.97 0.00 71.29 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 07/08/08 Sentinel 175.26 107.13 0.00 68.13 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-20 02/10/09 Sentinel 175.26 104.81 0.00 70.45 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-20 08/03/09 Sentinel 175.26 107.20 0.00 68.06 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-20 03/01/10 Sentinel 175.26 104.45 0.00 70.81 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-20 08/02/10 Sentinel 175.26 ------<50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-20 02/11/11 Sentinel 175.26 102.69 0.00 72.57 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-20 08/19/11 Sentinel 175.26 105.90 0.00 69.36 <50 <0.5 <0.5 <0.5 <0.5 <1 7,200 1,520,000 <14.1 --
FGW-20 03/08/12 Sentinel 175.26 104.23 0.00 71.03 <50 <0.5 <0.5 <0.5 <0.5 <1 7,100 1,340,000 <14.1 --
FGW-20 08/29/12 Sentinel 175.26 107.27 0.00 67.99 <50 <0.5 <0.5 <0.5 <0.5 <1 6,800 1,190,000 <33.3 6.92
FGW-20 03/28/13 Sentinel 175.26 105.04 0.00 70.22 <50 <0.5 <0.5 <0.5 <0.5 <1 7,200 1,250,000 <33.3 8.70
FGW-20 08/21/13 Sentinel 175.26 106.49 0.00 68.77 <50 <0.5 <0.5 <0.5 <0.5 <1 6,900 1,230,000 <43.0 3.20
FGW-20 03/19/14 Sentinel 175.26 102.09 0.00 73.17 <50 <0.5 <0.5 <0.5 <0.5 <1 8,100 1,230,000 <43.0 3.87
FGW-20 09/23/14 Sentinel 175.26 105.38 0.00 69.88 --------------------
FGW-20 03/26/15 Sentinel 175.26 103.71 0.00 71.55 <50 <0.5 <0.5 <0.5 <0.5 <1 3,700 359,000 <33.4 7.65
FGW-20 09/24/15 Sentinel 175.26 104.81 0.00 70.45 <50 <0.5 <0.5 <0.5 <0.5 <1 8,400 1,150,000 <33.3 5.08
FGW-20 09/29/16 Sentinel 175.26 105.56 0.00 69.70 <50 <0.5 <0.5 <0.5 <0.5 <1 7,800 1,240,000 <74.7 8.69
FGW-20 08/30/17 Sentinel 175.26 106.94 0.00 68.32 <50 <0.5 <0.5 <0.5 <0.5 <1 10,000 1,440,000 <80.5 7.98
FGW-20 11/07/18 Sentinel 175.26 103.95 0.00 71.31 <17 <0.2 <0.2 <0.2 <0.5 <4 10,700 837,000 <40.0 J 8.54
FGW-20 09/12/19 Sentinel 175.26 104.31 0.00 70.95 <17 <0.2 <0.2 <0.4 <1 <1 5,500 1,160,000 6,350* 2.38
FGW-20 9/29/2020 Sentinel 175.26 106.36 0.00 68.90 100 UB
<0.0941 <0.278 <0.137 <0.174 <1.00 7,680 1,350,000 131* 0.12
FGW-20 10/26/2021 Sentinel 175.26 108.52 0.00 66.74 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.0 J3 11,500 B T8 1,220,000 5,480* 6.90
211535_Tables Page 5 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
FGW-20 9/28/2022 Sentinel 175.26 109.29 0.00 65.97 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.0 8650**1,360,000 8,420*6.54
FGW-20 11/8/2023 Sentinel 175.26 109.29 0.00 65.97 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.00 9970**1,110,000 1,090*6.58
AGW-3 11/11/94 Upgradient 202.26 29.18 0.00 173.08 <0.5 <2 5 <2 <6 ----------
AGW-3 08/16/95 Upgradient 202.26 30.91 0.00 171.35 <0.5 <2 <2 <2 <6 ----------
AGW-3 12/09/95 Upgradient 202.26 39.50 0.00 162.76 --------------------
AGW-3 02/15/96 Upgradient 202.26 40.00 0.00 162.26 --------------------
AGW-3 05/09/96 Upgradient 202.26 --------------------------
AGW-3 09/04/98 Upgradient 202.26 31.50 0.00 170.76 <20 <1 <2 <2 <2 <4 --------
AGW-3 12/11/98 Upgradient 202.26 --------------------------
AGW-3 02/04/99 Upgradient 202.26 --------------------------
AGW-3 05/05/99 Upgradient 202.26 --------------------------
AGW-3 08/02/99 Upgradient 202.26 37.17 0.00 165.09 <20 <1 <2 <2 <2 <4 --------
AGW-3 11/03/99 Upgradient 202.26 32.16 0.00 170.10 <20 <1 <2 <2 <2 <4 --------
AGW-3 02/02/00 Upgradient 202.26 --------------------------
AGW-3 05/02/00 Upgradient 202.26 39.61 0.00 162.65 --------------------
AGW-3 08/02/00 Upgradient 202.26 32.20 0.00 170.06 --------------------
AGW-3 11/13/00 Upgradient 202.26 36.60 0.00 165.66 --------------------
AGW-3 02/21/01 Upgradient 202.26 --------------------------
AGW-3 05/30/01 Upgradient 202.26 25.35 0.00 176.91 --------------------
AGW-3 08/23/01 Upgradient 202.26 29.57 0.00 172.69 --------------------
AGW-3 12/12/01 Upgradient 202.26 --------------------------
AGW-3 02/21/02 Upgradient 202.26 --------------------------
AGW-3 05/15/02 Upgradient 202.26 24.33 0.00 177.93 --------------------
AGW-3 09/05/02 Upgradient 202.26 34.25 0.00 168.01 --------------------
AGW-3 11/21/02 Upgradient 202.26 39.35 0.00 162.91 --------------------
AGW-3 02/11/03 Upgradient 202.26 --------------------------
AGW-3 05/21/03 Upgradient 202.26 --------------------------
AGW-3 08/06/03 Upgradient 202.26 --------------------------
AGW-3 11/18/03 Upgradient 202.26 --------------------------
AGW-3 02/18/04 Upgradient 202.26 --------------------------
AGW-3 05/11/04 Upgradient 202.26 --------------------------
AGW-3 08/16/04 Upgradient 202.26 38.17 0.00 164.09 --------------------
AGW-3 11/10/04 Upgradient 202.26 --------------------------
AGW-3 02/02/05 Upgradient 202.26 --------------------------
AGW-3 05/09/05 Upgradient 202.26 --------------------------
AGW-3 08/16/05 Upgradient 202.26 36.39 0.00 165.87 --------------------
AGW-3 11/15/05 Upgradient 202.26 30.31 0.00 171.95 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
AGW-3 02/21/06 Upgradient 202.26 --------------------------
AGW-3 05/08/06 Upgradient 202.26 --------------------------
AGW-3 02/15/07 Upgradient 202.26 --------------------------
AGW-3 07/09/07 Upgradient 202.26 --------------------------
AGW-3 02/27/08 Upgradient 202.26 --------------------------
AGW-3 07/08/08 Upgradient 202.26 --------------------------
AGW-3 02/10/09 Upgradient 202.26 --------------------------
AGW-3 08/03/09 Upgradient 202.26 36.19 0.00 166.07 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
AGW-3 03/01/10 Upgradient 202.26 --------------------------
AGW-3 08/01/10 Upgradient 202.26 --------------------------
AGW-3 02/10/11 Upgradient 202.26 --------------------------
AGW-3 08/19/11 Upgradient 202.26 35.31 0.00 166.95 <50 <0.5 <0.5 <0.5 <0.5 <1 1,000 1,180,000 <14.1 --
AGW-3 03/08/12 Upgradient 202.26 --------------------------
AGW-3 08/28/12 Upgradient 202.26 37.58 0.00 164.68 <50 <0.5 <0.5 <0.5 <0.5 <1 1,400 1,030,000 <33.3 6.58
AGW-3 3/27/2013 Upgradient 202.26 --------------------------
AGW-3 8/21/2013 Upgradient 202.26 32.42 0.00 169.84 <50 <0.5 <0.5 <0.5 <0.5 <1 2,000 984,000 <43.0 4.99
AGW-3 3/18/2014 Upgradient 202.26 --------------------------
AGW-3 9/23/2014 Upgradient 202.26 32.57 0.00 169.69 <50 <0.5 <0.5 <0.5 <0.5 <1.0 680 808,000 <33.4 10.95
AGW-3 3/25/2015 Upgradient 202.26 39.41 0.00 162.85 --------------------
AGW-3 9/24/2015 Upgradient 202.26 35.45 0.00 166.81 <50 <0.5 <0.5 <0.5 <0.5 <1 730 1,080,000 <33.3 7.82
AGW-3 8/30/2017 Upgradient 202.26 DRY -- -------- -- -- ---- -- -- --
AGW-3 9/12/2019 Upgradient 202.26 DRY -- -------- -- -- ---- -- -- --
AGW-3 10/26/2021 Upgradient 202.26 -- -- --
FGW-18 09/20/05 Side Gradient 189.63 35.50 0.00 154.13 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-18 11/15/05 Side Gradient 189.63 31.20 0.00 158.43 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-18 02/21/06 Side Gradient 189.63 38.10 0.00 151.53 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-18 05/08/06 Side Gradient 189.63 44.28 0.00 145.35 --------------------
FGW-18 02/15/07 Side Gradient 189.63 44.25 0.00 145.38 <50 <0.5 <0.5 <0.5 1 <1.0 --------
Wells Sampled Biennially
Not located
211535_Tables Page 6 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
FGW-18 07/09/07 Side Gradient 189.63 --------------------------
FGW-18 02/07/08 Side Gradient 189.63 --------------------------
FGW-18 07/08/08 Side Gradient 189.63 --------------------------
FGW-18 02/10/09 Side Gradient 189.63 38.00 0.00 151.63 --<0.5 <0.5 <0.5 <0.5 <1 --------
FGW-18 08/03/09 Side Gradient 189.63 44.13 0.00 145.50 --------------------
FGW-18 03/01/10 Side Gradient 189.63 --------------------------
FGW-18 08/02/10 Side Gradient 189.63 37.96 0.00 151.67 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-18 02/10/11 Side Gradient 189.63 37.65 0.00 151.98 --------------------
FGW-18 08/18/11 Side Gradient 189.63 34.56 0.00 155.07 <50 <0.5 <0.5 <0.5 <0.5 <1 4,700 963,000 <14.1 --
FGW-18 03/08/12 Side Gradient 189.63 37.89 0.00 151.74 --------------------
FGW-18 08/28/12 Side Gradient 189.63 --------------------------
FGW-18 3/28/2013 Side Gradient 189.63 37.97 0.00 151.66 <50 <0.5 <0.5 <0.5 <0.5 <1 7,800 731,000 --8.48
FGW-18 8/21/2013 Side Gradient 189.63 --------------------------
FGW-18 3/18/2014 Side Gradient 189.63 37.97 0.00 151.66 ------------------8.05
FGW-18 9/23/2014 Side Gradient 189.63 33.87 0.00 155.76 <50 <0.5 <0.5 <0.5 <0.5 <1 5,200 902,000 <33.4 10.52
FGW-18 3/26/2015 Side Gradient 189.63 37.95 0.00 151.68 <50 <0.5 <0.5 <0.5 <0.5 <1 4,600 788,000 <33.4 12.42
FGW-18 9/24/2015 Side Gradient 189.63 34.48 0.00 155.15 <50 <0.5 <0.5 <0.5 <0.5 <1 3,700 752,000 <33.3 7.16
FGW-18 8/30/2017 Side Gradient 189.63 37.90 0.00 151.73
FGW-18 9/12/2019 Side Gradient -- -- -- --
FGW-19 09/20/05 Side Gradient 195.15 114.40 0.00 80.75 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 11/15/05 Side Gradient 195.15 113.57 0.00 81.58 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 02/21/06 Side Gradient 195.15 111.43 0.00 83.72 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 05/08/06 Side Gradient 195.15 115.65 0.00 79.50 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 02/15/07 Side Gradient 195.15 103.00 0.00 92.15 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 07/09/07 Side Gradient 195.15 121.35 0.00 73.80 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 02/27/08 Side Gradient 195.15 117.16 0.00 77.99 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 07/08/08 Side Gradient 195.15 119.81 0.00 75.34 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
FGW-19 02/10/09 Side Gradient 195.15 117.33 0.00 77.82 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-19 08/03/09 Side Gradient 195.15 118.97 0.00 76.18 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-19 03/01/10 Side Gradient 195.15 116.82 0.00 78.33 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-19 08/01/10 Side Gradient 195.15 119.34 0.00 75.81 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-19 02/11/11 Side Gradient 195.15 113.45 0.00 81.70 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
FGW-19 08/19/11 Side Gradient 195.15 117.66 0.00 77.49 <50 [<50]<0.5 [<0.5]<0.5 [<0.5]<0.5 [<0.5]<0.5 [<0.5]<1 [<1]4,500 [4,700]1,700,000 [1,620,000]<14.1 [<14.1]--
FGW-19 3/8/2012 Side Gradient 195.15 117.32 0.00 77.83 <50 <0.5 <0.5 <0.5 <0.5 <1 5,100 1,480,000 <14.1 --
FGW-19 08/29/12 Side Gradient 195.15 118.81 0.00 76.34 <50 <0.5 <0.5 <0.5 <0.5 <1 4,800 1,550,000 <33.3 7.14
FGW-19 3/28/2013 Side Gradient 195.15 117.94 0.00 77.21 <50 <0.5 <0.5 <0.5 <0.5 <1 5,500 1,490,000 <33.3 9.98
FGW-19 8/21/2013 Side Gradient 195.15 119.09 0.00 76.06 <50 <0.5 <0.5 <0.5 <0.5 <1 5,800 1,510,000 <43.0 3.43
FGW-19 3/19/2014 Side Gradient 195.15 115.73 0.00 79.42 <50 <0.5 <0.5 <0.5 <0.5 <1 6,300 1,410,000 <43.0 2.74
FGW-19 9/23/2014 Side Gradient 195.15 117.44 0.00 77.71 <50 <0.5 <0.5 <0.5 <0.5 <1 5,300 1,550,000 <33.4 8.92
FGW-19 3/26/2015 Side Gradient 195.15 117.09 0.00 78.06 <50 <0.5 <0.5 <0.5 <0.5 <1 7,600 1,340,000 <33.4 7.43
FGW-19 9/24/2015 Side Gradient 195.15 116.60 0.00 78.55 <50 <0.5 <0.5 <0.5 <0.5 <1 7,200 1,420,000 <33.3 6.41
FGW-19 8/30/2017 Side Gradient 195.15 118.78 0.00 76.37 <50 <0.5 <0.5 <0.5 <0.5 <1 4,400 1,780,000 <80.5 8.41
FGW-19 9/12/2019 Side Gradient 195.15 105.66 0.00 89.49 <17 <0.2 <0.2 <0.4 <1 <1 3,500 1,710,000 1,910* 2.70
FGW-19 10/26/2021 Side Gradient 195.15 121.92 0.00 73.23 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.0 J3 9,890 T8 1,330,000 6,490* 6.46
FGW-19 11/8/2023 Side Gradient 195.15 -- -- --<31.4 <0.0941 <0.278 <0.137 <0.174 <1.00 5910** 1,350,000 2,370* 6.43
AGW-2 11/11/94 200.20 30.05 0.00 170.15 712,000 50,600 63,800 3,520 21,500 ---- -- -- --
AGW-2 08/16/95 200.20 31.74 0.00 168.46 340,000 42,900 57,400 2,240 17,000 ---- -- -- --
AGW-2 12/09/95 200.20 38.38 0.00 161.82 273,000 37,100 55,800 2,270 18,200 ---- -- -- --
AGW-2 02/15/96 200.20 42.04 0.00 158.16 274,000 38,200 49,900 2,190 18,400 ---- -- -- --
AGW-2 05/09/96 200.20 40.21 Sheen 159.99 -- -- -- -- -- ---- -- -- --
AGW-2 09/04/98 200.20 33.57 0.00 166.63 160,000 47,000 67,000E 2,900 24,000 <2,000 -- -- -- --
AGW-2 12/11/98 200.20 40.21 0.21 160.15 -- -- -- -- -- ---- -- -- --
AGW-2 02/04/99 200.20 42.19 0.76 158.58 -- -- -- -- -- ---- -- -- --
AGW-2 05/05/99 200.20 44.38 0.43 156.14 -- -- -- -- -- ---- -- -- --
AGW-2 06/02/99 200.20 43.54 0.62 157.13 -- -- -- -- -- ---- -- -- --
AGW-2 08/02/99 200.20 37.70 0.06 162.55 260,000 18,000E 12,000E 1,900 11,000 590 -- -- -- --
AGW-2 11/03/99 200.20 32.50 0.00 167.70 94,000 34,000E 36,000E 2,300 17,000 <400 -- -- -- --
AGW-2 02/02/00 200.20 40.17 0.21 160.19 --------------------
AGW-2 05/02/00 200.20 41.16 0.36 159.31 --------------------
AGW-2 08/02/00 200.20 35.32 0.00 164.88 --------------------
AGW-2 11/13/00 200.20 35.49 0.49 165.08 --------------------
AGW-2 02/21/01 200.20 40.90 0.12 159.39 --------------------
AGW-2 05/30/01 200.20 26.79 Sheen 173.41 --------------------
AGW-2 08/23/01 200.20 30.87 0.00 169.33 --------------------
Abandoned Wells
Insufficient water for sampling
Not located
211535_Tables Page 7 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
AGW-2 12/12/01 200.20 29.42 0.00 170.78 --------------------
AGW-2 02/21/02 200.20 38.47 0.06 161.78 --------------------
AGW-2 05/15/02 200.20 25.80 0.00 174.40 --------------------
AGW-2 09/05/02 200.20 34.55 0.00 165.65 --------------------
AGW-2 11/21/02 200.20 38.93 0.00 161.27 93,000 1,100 11,000 1,600 20,000 490 --------
AGW-2 02/11/03 200.20 42.65 0.52 157.94 --------------------
AGW-2 03/19/03 200.20 43.37 0.08 156.89 --------------------
AGW-2 05/21/03 200.20 43.81 0.06 156.44 --------------------
AGW-2 06/25/03 200.20 43.23 0.43 157.29 --------------------
AGW-2 07/10/03 200.20 42.26 0.52 158.33 --------------------
AGW-2 08/06/03 200.20 41.78 0.44 158.75 --------------------
AGW-2 09/25/03 200.20 41.56 0.46 158.99 --------------------
AGW-2 10/23/03 200.20 41.52 0.51 159.06 --------------------
AGW-2 11/19/03 200.20 38.88 0.00 161.32 44,000 690 2,300 630 7,400 500 --------
AGW-2 12/15/03 200.20 40.87 0.00 159.33 --------------------
AGW-2 01/14/04 200.20 42.19 0.00 158.01 --------------------
AGW-2 02/19/04 200.20 43.89 0.01 156.32 19,000 440 800 490 3,300 250 --------
AGW-2 03/10/04 200.20 44.62 0.02 155.60 --------------------
AGW-2 05/11/04 200.20 44.48 0.00 155.72 24,000 360 680 430 2,900 220 --------
AGW-2 06/28/04 200.20 41.50 0.00 158.70 --------------------
AGW-2 07/12/04 200.20 40.72 0.00 159.48 --------------------
AGW-2 08/16/04 200.20 39.00 0.00 161.20 20,000 720 790 440 1,700 180 --------
AGW-2 09/08/04 200.20 39.38 0.00 160.82 --------------------
AGW-2 10/06/04 200.20 40.15 0.00 160.05 --------------------
AGW-2 11/10/04 200.20 40.59 0.00 159.61 16,000 760 460 480 1,500 220 --------
AGW-2 12/14/04 200.20 42.53 0.00 157.67 --------------------
AGW-2 01/25/05 200.20 44.35 0.00 155.85 --------------------
AGW-2 02/02/05 200.20 44.65 0.00 155.55 18,000 430 130 510 1,800 280 --------
AGW-2 03/17/05 200.20 46.32 0.04 153.91 --------------------
AGW-2 05/09/05 200.20 46.79 0.03 153.43 22,000 830 130 990 3,000 330 --------
AGW-2 06/07/05 200.20 45.12 0.00 155.08 --------------------
AGW-2 07/18/05 200.20 38.12 0.00 162.08 --------------------
AGW-2 08/16/05 200.20 37.73 0.00 162.47 14,000 620 64 500 1,600 190 --------
AGW-2 10/28/05 200.20 32.38 0.00 167.82 --------------------
AGW-2 11/16/05 200.20 31.47 0.00 168.73 16,000 280 78 110 840 450 --------
AGW-2 01/26/06 200.20 39.49 0.00 160.71 --------------------
AGW-2 02/21/06 200.20 41.03 0.00 159.17 --------------------
AGW-2 05/08/06 200.20 42.31 0.00 157.89 --------------------
AGW-2 10/09/07 200.20 --------------------------
BGW-4A 02/15/96 199.88 35.05 0.00 164.83 --------------------
BGW-4A 05/09/96 199.88 --------------------------
BGW-4A 09/04/98 199.88 33.80 0.00 166.08 120,000 33,000E 51,000E 3,700 27,000 <400 --------
BGW-4A 12/11/98 199.88 39.87 0.00 160.01 --------------------
BGW-4A 02/04/99 199.88 42.08 0.00 157.80 73,000 23,000E 22,000E 2,000 15,000E 410 --------
BGW-4A 04/15/99 199.88 44.93 0.92 155.64 --------------------
BGW-4A 05/05/99 199.88 44.42 1.00 156.21 --------------------
BGW-4A 06/02/99 199.88 43.07 0.42 157.13 --------------------
BGW-4A 08/02/99 199.88 37.90 0.00 161.98 130,000 95,000E 6,300E 1,700 7,500 530 --------
BGW-4A 11/02/99 199.88 32.78 0.00 167.10 80,000 19,000E 21,000E 3,100 23,000E 310 --------
BGW-4A 02/02/00 199.88 39.50 0.00 160.38 810,000 19,000 58,000E 16,000 140,000E 8,300 --------
BGW-4A 05/02/00 199.88 40.66 0.20 159.37 --------------------
BGW-4A 08/02/00 199.88 35.70 Sheen 164.18 --------------------
BGW-4A 11/13/00 199.88 35.46 Sheen 164.42 65,000 5,300 17,000E 1,700 19,000 500 --------
BGW-4A 01/08/01 199.88 38.97 0.06 160.96 --------------------
BGW-4A 02/21/01 199.88 40.69 0.15 159.30 --------------------
BGW-4A 05/30/01 199.88 27.05 0.03 172.85 190,000 260 4,900 1,400 13,300 <250 --------
BGW-4A 08/23/01 199.88 31.28 0.04 168.63 --------------------
BGW-4A 12/12/01 199.88 29.81 0.00 170.07 21,000 16 116 <100 1,802 195 --------
BGW-4A 02/21/02 199.88 38.21 0.01 161.68 31,000 730 2,900 153 1,293 133 --------
BGW-4A 05/15/02 199.88 26.34 0.00 173.54 11,000 16 200 30 2,300 100 --------
BGW-4A 09/05/02 199.88 34.73 0.00 165.15 19,000 290 1,300 210 1,500 85 --------
BGW-4A 11/21/02 199.88 38.42 0.00 161.46 35,000 1,200 3,500 670 5,100 190 --------
BGW-4A 02/11/03 199.88 42.36 0.02 157.54 --------------------
BGW-4A 03/25/03 199.88 43.90 0.19 156.12 --------------------
BGW-4A 04/15/03 199.88 44.79 0.44 155.42 --------------------
BGW-4A 05/21/03 199.88 43.57 0.13 156.41 --------------------
BGW-4A 06/17/03 199.88 42.72 0.05 157.20 --------------------
211535_Tables Page 8 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
BGW-4A 07/10/03 199.88 41.60 0.00 158.28 --------------------
BGW-4A 08/06/03 199.88 41.12 0.01 158.77 76,000 1,200 8,300 1,100 14,000 380 --------
BGW-4A 09/25/03 199.88 40.99 0.00 158.89 --------------------
BGW-4A 11/18/03 199.88 38.59 0.00 161.29 59,000 610 3,300 1,100 13,000 430 --------
BGW-4A 12/15/03 199.88 40.50 0.00 159.38 --------------------
BGW-4A 02/19/04 199.88 43.55 0.02 156.35 35,000 460 450 1,100 7,000 400 --------
BGW-4A 03/10/04 199.88 44.28 0.01 155.61 --------------------
BGW-4A 04/12/04 199.88 45.52 0.39 154.65 --------------------
BGW-4A 05/11/04 199.88 44.14 0.05 155.78 55,000 360 4,000 1,400 11,000 390 --------
BGW-4A 07/12/04 199.88 40.41 0.00 159.47 --------------------
BGW-4A 08/16/04 199.88 38.71 0.00 161.17 40,000 410 1,900 1,200 10,000 490 --------
BGW-4A 10/06/04 199.88 39.84 0.01 160.05 --------------------
BGW-4A 11/10/04 199.88 40.27 0.00 159.61 36,000 520 140 1,200 8,100 580 --------
BGW-4A 01/25/05 199.88 44.00 0.00 155.88 --------------------
BGW-4A 02/02/05 199.88 44.30 0.00 155.58 38,000 390 640 1,800 7,800 850 --------
BGW-4A 02/25/05 199.88 45.96 0.25 154.11 --------------------
BGW-4A 03/17/05 199.88 45.98 0.20 154.05 --------------------
BGW-4A 05/09/05 199.88 46.53 0.13 153.45 --------------------
BGW-4A 06/17/05 199.88 43.97 0.00 155.91 --------------------
BGW-4A 07/18/05 199.88 37.85 0.00 162.03 --------------------
BGW-4A 08/16/05 199.88 37.41 0.00 162.47 11,000 310 25 150 1,300 150 --------
BGW-4A 11/16/05 199.88 31.23 0.00 168.65 8,100 31 10 120 530 180 --------
BGW-4A 02/21/06 199.88 40.70 0.00 159.18 --------------------
BGW-4A 05/08/06 199.88 41.93 0.00 157.95 --------------------
BGW-4A 10/09/07 199.88 --------------------------
BGW-6 09/04/98 199.71 33.59 0.00 166.12 56,000 9,500E 16,000E 2,400E 16,000E 290 --------
BGW-6 12/11/98 199.71 39.72 0.00 159.99 --------------------
BGW-6 02/04/99 199.71 42.01 0.00 157.70 76,000 15,000E 23,000E 2,600 15,000 390 --------
BGW-6 04/15/99 199.71 44.95 0.90 155.44 --------------------
BGW-6 05/05/99 199.71 44.41 1.08 156.11 --------------------
BGW-6 06/02/99 199.71 43.21 0.65 156.99 --------------------
BGW-6 08/02/99 199.71 37.33 0.03 162.40 160,000 12,000E 7,400E 2,000 8,900 580 --------
BGW-6 11/04/99 199.71 32.76 0.00 166.95 50,000 11,000E 19,000E 2,000 13,000 460 --------
BGW-6 02/02/00 199.71 39.62 0.02 160.11 330,000 19,000 56,000E 7,400 64,000 2,800 --------
BGW-6 05/02/00 199.71 40.44 0.00 159.27 200,000 16,000 42,000E 3,400 28,000 1,200 --------
BGW-6 08/02/00 199.71 35.50 0.00 164.21 240,000 8,000 27,000E 4,200 29,000 1,000 --------
BGW-6 11/13/00 199.71 35.30 Sheen 164.41 130,000 6,900 24,000 E 3,500 31,000 E 980 --------
BGW-6 02/21/01 199.71 40.31 0.00 159.40 93,000 6,300 29,000E 2,400 23,000 370 --------
BGW-6 05/31/01 199.71 26.56 0.01 173.16 97,000 3,000 20,000 1,200 12,200 <1,000 --------
BGW-6 08/23/01 199.71 30.90 0.00 168.81 13,000 <1,000 12,000 <1,000 9,900 <1,000 --------
BGW-6 12/12/01 199.71 28.76 0.00 170.95 1,900 9 140 25 605 81 --------
BGW-6 02/21/02 199.71 38.01 0.00 161.70 83,000 607 12,600 1,510 11,120 964 --------
BGW-6 05/15/02 199.71 25.40 0.00 174.31 2,000 9 190 7 440 3 --------
BGW-6 09/05/02 199.71 34.50 0.00 165.21 64,000 240 6,900 1,000 11,000 210 --------
BGW-6 11/21/02 199.71 38.61 0.00 161.10 49,000 230 6,600 1,400 12,000 180 --------
BGW-6 02/11/03 199.71 42.34 0.00 157.37 33,000 [31,000]210 [200]1,300 [1,100]940 [950]5,100 [4,900]210 [220]--------
BGW-6 04/15/03 199.71 44.86 0.60 155.30 --------------------
BGW-6 05/21/03 199.71 43.57 0.20 156.29 --------------------
BGW-6 06/17/03 199.71 42.64 0.00 157.07 --------------------
BGW-6 08/06/03 199.71 41.12 0.02 158.61 63,000 240 4,100 1,200 11,000 410 --------
BGW-6 11/18/03 199.71 38.49 0.00 161.22 66,000 220 4,100 1,000 12,000 440 --------
BGW-6 02/19/04 199.71 43.52 0.00 156.19 29,000 140 450 790 5,300 250 --------
BGW-6 04/12/04 199.71 45.49 0.39 154.51 --------------------
BGW-6 05/11/04 199.71 44.04 0.01 155.68 35,000 120 1,100 1,300 9,000 670 --------
BGW-6 07/12/04 199.71 40.37 0.00 159.34 --------------------
BGW-6 08/16/04 199.71 38.68 0.00 161.03 27,000 67 900 670 5,700 340 --------
BGW-6 11/10/04 199.71 40.24 0.00 159.47 23,000 69 260 620 4,400 350 --------
BGW-6 02/02/05 199.71 44.30 0.00 155.41 17,000 100 48 620 2,000 210 --------
BGW-6 05/09/05 199.71 46.41 0.00 153.30 20,000 170 210 980 3,600 330 --------
BGW-6 08/16/05 199.71 37.31 0.00 162.40 11,000 80 58 230 1,600 140 --------
BGW-6 11/16/05 199.71 30.85 0.00 168.86 12,000 27 27 220 1,500 120 --------
BGW-6 02/21/06 199.71 40.69 0.00 159.02 --------------------
BGW-6 05/08/06 199.71 41.93 0.00 157.78 --------------------
BGW-6 10/09/07 199.71 --------------------------
BGW-7 09/04/98 198.90 32.94 0.00 165.96 110,000 19,000 36,000E 3,100 23,000 <1,000 --------
BGW-7 12/11/98 198.90 38.77 0.00 160.13 --------------------
211535_Tables Page 9 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
BGW-7 02/04/99 198.90 40.95 0.00 157.95 70,000 23,000E 21,000E 2,000 14,000 490 --------
BGW-7 04/15/99 198.90 44.02 1.01 155.64 --------------------
BGW-7 05/05/99 198.90 43.44 1.04 156.24 --------------------
BGW-7 06/02/99 198.90 42.04 0.30 157.09 --------------------
BGW-7 08/02/99 198.90 36.95 0.00 161.95 320,000 24,000 20,000 7,100 38,000 <2,000 --------
BGW-7 11/02/99 198.90 31.94 0.00 166.96 72,000 18,000E 23,000E 2,700 20,000E 290 --------
BGW-7 02/02/00 198.90 38.75 0.09 160.22 --------------------
BGW-7 05/02/00 198.90 39.66 0.10 159.32 110,000 20,000 40,000 2,600 20,000 480 --------
BGW-7 08/02/00 198.90 34.95 Sheen 163.95 --------------------
BGW-7 11/13/00 198.90 34.49 0.01 164.42 --------------------
BGW-7 02/21/01 198.90 39.72 0.07 159.23 --------------------
BGW-7 05/30/01 198.90 26.56 Sheen 172.34 --------------------
BGW-7 08/23/01 198.90 30.49 Sheen 168.41 130,000 4,156 19,000 1,500 15,310 1,100 --------
BGW-7 12/12/01 198.90 29.10 0.00 169.80 --------------------
BGW-7 02/21/02 198.90 37.52 0.00 161.38 --------------------
BGW-7 05/15/02 198.90 25.88 0.00 173.02 --------------------
BGW-7 09/05/02 198.90 33.87 0.00 165.03 110,000 5,400 16,000 1,600 17,000 400 --------
BGW-7 11/21/02 198.90 37.78 0.00 161.12 130,000 7,200 20,000 1,800 18,000 330 --------
BGW-7 02/11/03 198.90 41.53 0.23 157.54 --------------------
BGW-7 03/06/03 198.90 43.70 1.42 156.27 --------------------
BGW-7 04/15/03 198.90 44.69 1.30 155.19 --------------------
BGW-7 05/21/03 198.90 43.35 0.84 156.18 --------------------
BGW-7 06/25/03 198.90 42.10 0.40 157.10 --------------------
BGW-7 08/06/03 198.90 40.11 0.00 158.79 38,000 190 730 220 3,600 210 --------
BGW-7 09/25/03 198.90 40.12 0.00 158.78 --------------------
BGW-7 11/19/03 198.90 37.65 0.00 161.25 44,000 980 3,300 440 7,200 430 --------
BGW-7 02/18/04 198.90 42.61 0.00 156.29 39,000 100 1,600 570 6,600 280 --------
BGW-7 03/10/04 198.90 44.05 0.90 155.53 --------------------
BGW-7 04/12/04 198.90 45.19 1.15 154.57 --------------------
BGW-7 05/11/04 198.90 43.34 0.04 155.59 62,000 300 5,800 1,300 12,000 470 --------
BGW-7 07/12/04 198.90 39.45 0.00 159.45 --------------------
BGW-7 08/16/04 198.90 37.71 0.00 161.19 5,300 52 99 50 510 97 --------
BGW-7 09/08/04 198.90 38.08 0.00 160.82 --------------------
BGW-7 11/11/04 198.90 39.27 0.00 159.63 7,000 56 46 38 650 150 --------
BGW-7 02/02/05 198.90 43.28 0.00 155.62 19,000 470 1,200 860 6,300 450 --------
BGW-7 03/17/05 198.90 45.26 0.04 153.67 --------------------
BGW-7 05/09/05 198.90 45.44 0.00 153.46 10,000 300 78 370 1,100 220 --------
BGW-7 08/16/05 198.90 36.44 0.00 162.46 4,500 56 3 40 460 90 --------
BGW-7 11/16/05 198.90 30.45 0.00 168.45 11,000 170 12 76 830 190 --------
BGW-7 02/21/06 198.90 39.72 0.00 159.18 --------------------
BGW-7 05/08/06 198.90 40.94 0.00 157.96 --------------------
BGW-7 10/10/07 198.90 --------------------------
BGW-8 09/04/98 199.02 33.14 0.00 165.88 38,000 5,700E 11,000E 1,500 10,000E 150 --------
BGW-8 12/11/98 199.02 40.91 0.00 158.11 --------------------
BGW-8 02/04/99 199.02 41.24 0.00 157.78 17,000 3,300E 2,700E 180 2,400 50 --------
BGW-8 05/05/99 199.02 45.49 0.00 153.53 7,700 680E 540E 12 1,400E 15 --------
BGW-8 08/02/99 199.02 36.95 0.00 162.07 22,000 1,200E 380E 110 510 16 --------
BGW-8 11/02/99 199.02 32.14 0.00 166.88 25,000 4,100E 4,200E 1,300 8,900E 140 --------
BGW-8 02/02/00 199.02 --------------------------
BGW-8 05/02/00 199.02 41.68 0.00 157.34 8,200 2,500E 710 200 590 <400 --------
BGW-8 08/02/00 199.02 34.90 0.00 164.12 4,900 940E 180 28 1,400 41 --------
BGW-8 11/13/00 199.02 34.70 0.00 164.32 6,600 1,300 62 <10 2,400 96 --------
BGW-8 02/21/01 199.02 41.02 0.00 158.00 6,500 2 150 210 1,100 43 --------
BGW-8 05/30/01 199.02 26.62 0.00 172.40 <100 <5 <5 <5 <5 <5 --------
BGW-8 08/23/01 199.02 30.52 0.00 168.50 1,800 130 32 <5 290 8 --------
BGW-8 12/12/01 199.02 28.10 0.00 170.92 140 12 8 6 110 27 --------
BGW-8 02/21/02 199.02 37.30 0.00 161.72 6,800 874 31 17 308 60 --------
BGW-8 05/15/02 199.02 25.74 0.00 173.28 <50 <0.5 <0.5 <0.5 <0.5 1 --------
BGW-8 09/05/02 199.02 33.96 0.00 165.06 6,800 1,300 41 11 450 46 --------
BGW-8 11/21/02 199.02 37.80 0.00 161.22 4,200 1,100 34 55 210 45 --------
BGW-8 02/11/03 199.02 42.93 0.00 156.09 4,000 260 8 <0.8 32 1 --------
BGW-8 05/21/03 199.02 44.78 0.00 154.24 400 82 6 2 10 1 --------
BGW-8 08/06/03 199.02 42.30 0.00 156.72 2,000 540 22 36 36 6 --------
BGW-8 11/19/03 199.02 38.11 0.00 160.91 67 17 1 1 1 <1 --------
BGW-8 05/11/04 199.02 45.57 0.00 153.45 330 34 24 5 50 2 --------
BGW-8 06/17/04 199.02 43.73 0.01 155.30 --------------------
BGW-8 07/12/04 199.02 42.60 0.00 156.42 --------------------
211535_Tables Page 10 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
BGW-8 08/16/04 199.02 39.61 0.00 159.41 260 82 2 <0.5 4 <1 --------
BGW-8 11/11/04 199.02 41.73 0.00 157.29 <50 15 <0.7 <0.8 <0.8 <1 --------
BGW-8 02/02/05 199.02 45.56 0.00 153.46 <50 1 <0.7 <0.8 <0.8 <1 --------
BGW-8 05/09/05 199.02 47.35 0.00 151.67 <50 3 1 <0.5 1 <1 --------
BGW-8 08/16/05 199.02 36.99 0.00 162.03 <50 1 <0.5 <0.5 <0.5 2 --------
BGW-8 11/16/05 199.02 30.56 0.00 168.46 140 10 3 <0.5 29 2 --------
BGW-8 02/21/06 199.02 41.94 0.00 157.08 --------------------
BGW-8 05/08/06 199.02 37.02 0.00 162.00 --------------------
BGW-8 02/15/07 199.02 45.82 0.00 153.20 --------------------
BGW-8 07/09/07 199.02 45.19 0.00 153.83 --------------------
BGW-8 10/10/07 199.02 --------------------------
BGW-9 09/04/98 199.20 33.23 0.00 165.97 66,000 20,000E 30,000E 1,900 14,000 <400 --------
BGW-9 12/11/98 199.20 39.10 0.00 160.10 --------------------
BGW-9 02/04/99 199.20 41.24 0.58 158.40 66,000 11,000E 18,000E 3,000 13,000 460 --------
BGW-9 04/15/99 199.20 44.23 0.91 155.65 --------------------
BGW-9 05/05/99 199.20 43.73 0.93 156.17 --------------------
BGW-9 06/02/99 199.20 42.50 0.51 157.08 --------------------
BGW-9 08/02/99 199.20 36.79 0.00 162.41 2,600 170 170 22 130 <8 --------
BGW-9 11/04/99 199.20 32.44 0.00 166.76 56,000 16,000E 20,000E 2,200 13,000 490 --------
BGW-9 02/02/00 199.20 39.02 0.04 160.21 --------------------
BGW-9 05/02/00 199.20 39.92 0.04 159.31 --------------------
BGW-9 08/02/00 199.20 35.15 0.00 164.05 --------------------
BGW-9 11/13/00 199.20 34.90 0.00 164.30 --------------------
BGW-9 02/21/01 199.20 39.94 0.01 159.27 --------------------
BGW-9 05/30/01 199.20 26.85 Sheen 172.35 --------------------
BGW-9 08/23/01 199.20 30.78 Sheen 168.42 --------------------
BGW-9 12/13/01 199.20 29.42 0.00 169.78 49,000 1,390 4,690 986 7,460 420 --------
BGW-9 02/21/02 199.20 37.69 0.00 161.51 90,000 1,910 13,100 1,460 9,890 792 --------
BGW-9 05/15/02 199.20 26.14 0.00 173.06 79,000 1,600 12,000 1,200 13,000 340 --------
BGW-9 09/05/02 199.20 34.19 0.00 165.01 92,000 1,500 11,000 1,300 14,000 330 --------
BGW-9 11/21/02 199.20 38.12 0.00 161.08 72,000 1,600 12,000 1,400 12,000 290 --------
BGW-9 02/11/03 199.20 41.96 0.36 157.51 --------------------
BGW-9 03/25/03 199.20 43.48 0.49 156.09 --------------------
BGW-9 04/15/03 199.20 44.30 0.56 155.32 --------------------
BGW-9 05/21/03 199.20 42.99 0.13 156.31 --------------------
BGW-9 06/17/03 199.20 42.07 0.03 157.15 --------------------
BGW-9 08/06/03 199.20 40.47 0.00 158.73 70,000 930 10,000 1,600 13,000 570 --------
BGW-9 11/19/03 199.20 37.97 0.00 161.23 21,000 240 780 110 2,600 290 --------
BGW-9 12/15/03 199.20 39.91 0.00 159.29 --------------------
BGW-9 01/14/04 199.20 41.15 0.00 158.05 --------------------
BGW-9 02/18/04 199.20 42.91 0.01 156.30 57,000 750 8,000 1,400 11,000 390 --------
BGW-9 03/10/04 199.20 43.96 0.48 155.60 --------------------
BGW-9 04/12/04 199.20 45.13 0.72 154.61 --------------------
BGW-9 05/11/04 199.20 43.63 0.06 155.62 57,000 700 7,600 1,300 11,000 910 --------
BGW-9 06/17/04 199.20 41.37 0.01 157.84 --------------------
BGW-9 07/12/04 199.20 39.82 0.01 159.39 --------------------
BGW-9 08/16/04 199.20 38.06 0.00 161.14 51,000 43 610 880 6,900 650 --------
BGW-9 09/08/04 199.20 38.42 0.00 160.78 --------------------
BGW-9 11/11/04 199.20 39.61 0.00 159.59 35,000 140 190 1,200 10,000 920 --------
BGW-9 12/14/04 199.20 41.48 0.00 157.72 --------------------
BGW-9 02/02/05 199.20 43.61 0.01 155.60 52,000 680 5,700 1,700 10,000 700 --------
BGW-9 03/17/05 199.20 45.44 0.04 153.79 --------------------
BGW-9 05/09/05 199.20 45.78 Sheen 153.42 36,000 770 3,000 1,300 7,900 610 --------
BGW-9 06/07/05 199.20 44.22 0.05 155.02 --------------------
BGW-9 07/18/05 199.20 37.20 0.00 162.00 --------------------
BGW-9 08/16/05 199.20 36.78 0.00 162.42 4,600 28 58 89 850 69 --------
BGW-9 11/16/05 199.20 30.79 0.00 168.41 9,100 140 30 200 910 150 --------
BGW-9 01/26/06 199.20 38.49 0.00 160.71 --------------------
BGW-9 02/21/06 199.20 40.04 0.00 159.16 --------------------
BGW-9 04/06/06 199.20 41.65 0.00 157.55 --------------------
BGW-9 05/08/06 199.20 41.22 0.00 157.98 --------------------
BGW-9 02/15/07 199.20 43.45 0.02 155.77 --------------------
BGW-9 07/09/07 199.20 44.24 0.00 154.96 --------------------
BGW-9 10/10/07 199.20 --------------------------
CGW-10 10/02/98 198.62 51.70 0.00 146.92 120 26 24 <2 17 <4 --------
CGW-10 12/11/98 198.62 51.17 0.00 147.45 --------------------
211535_Tables Page 11 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
CGW-10 02/05/99 198.62 53.38 0.00 145.24 59 2 8 <2 15 5 --------
CGW-10 05/05/99 198.62 53.80 0.00 144.82 --------------------
CGW-10 08/02/99 198.62 64.13 0.00 134.49 --------------------
CGW-10 11/02/99 198.62 50.55 0.00 148.07 <20 4 7 <2 8 <4 --------
CGW-10 02/02/00 198.62 51.60 0.00 147.02 --------------------
CGW-10 05/02/00 198.62 53.79 0.00 144.83 --------------------
CGW-10 08/02/00 198.62 50.95 0.00 147.67 --------------------
CGW-10 11/13/00 198.62 50.93 0.00 147.69 --------------------
CGW-10 02/21/01 198.62 50.91 0.00 147.71 --------------------
CGW-10 05/30/01 198.62 50.52 0.00 148.10 --------------------
CGW-10 08/23/01 198.62 49.97 0.00 148.65 --------------------
CGW-10 12/13/01 198.62 --------------------------
CGW-10 02/21/02 198.62 50.52 0.00 148.10 --------------------
CGW-10 05/15/02 198.62 50.37 0.00 148.25 --------------------
CGW-10 09/05/02 198.62 50.70 0.00 147.92 51,000 7,100 6,900 440 3,800 110 --------
CGW-10 11/21/02 198.62 50.98 0.00 147.64 16,000 3,100 2,100 130 1,600 48 --------
CGW-10 02/11/03 198.62 53.12 0.00 145.50 2,000 990 82 26 310 21 --------
CGW-10 05/21/03 198.62 --------------------------
CGW-10 08/06/03 198.62 54.08 0.00 144.54 --------------------
CGW-10 11/18/03 198.62 54.09 0.00 144.53 --------------------
CGW-10 02/18/04 198.62 54.10 0.00 144.52 --------------------
CGW-10 05/11/04 198.62 54.09 0.00 144.53 --------------------
CGW-10 08/16/04 198.62 54.09 0.00 144.53 --------------------
CGW-10 11/10/04 198.62 54.20 0.00 144.42 --------------------
CGW-10 02/02/05 198.62 54.10 0.00 144.52 --------------------
CGW-10 05/09/05 198.62 54.09 0.00 144.53 --------------------
CGW-10 08/16/05 198.62 53.37 0.00 145.25 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
CGW-10 11/15/05 198.62 51.26 0.00 147.36 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
CGW-10 02/21/06 198.62 51.24 0.00 147.38 --------------------
CGW-10 05/08/06 198.62 53.60 0.00 145.02 --------------------
CGW-10 02/15/07 198.62 53.85 0.00 144.77 --------------------
CGW-10 07/09/07 198.62 53.82 0.00 144.80 --------------------
CGW-10 10/10/07 198.62 --------------------------
CGW-13 10/02/98 199.08 34.85 0.00 164.23 48,000 630 7,800E 3,200E 17,000E 920 --------
CGW-13 12/11/98 199.08 39.05 0.15 160.14 --------------------
CGW-13 02/04/99 199.08 41.19 0.23 158.06 48,000 530 7,700E 1,300 12,000 520 --------
CGW-13 04/15/99 199.08 44.09 0.88 155.65 --------------------
CGW-13 05/05/99 199.08 43.61 0.97 156.20 --------------------
CGW-13 06/02/99 199.08 42.23 0.36 157.12 --------------------
CGW-13 08/02/99 199.08 36.59 0.00 162.49 320,000 560 1,300E 570 2,400 310 --------
CGW-13 11/02/99 199.08 32.20 0.00 166.88 30,000 570 5,100E 710 11,000E 320 --------
CGW-13 02/02/00 199.08 38.85 0.15 160.34 32,000 940 6,400 550 11,000 <400 --------
CGW-13 05/02/00 199.08 39.74 0.00 159.34 40,000 480 6,000E 930 12,000E 430 --------
CGW-13 08/03/00 199.08 35.01 Sheen 164.07 --------------------
CGW-13 11/13/00 199.08 34.68 Sheen 164.40 25,000 190 3,700 260 8,800 320 --------
CGW-13 02/21/01 199.08 39.87 0.16 159.33 --------------------
CGW-13 05/30/01 199.08 26.86 0.00 172.22 3,400 <10 91 11 430 53 --------
CGW-13 08/23/01 199.08 30.77 0.00 168.31 6,000 <100 270 <100 1,800 210 --------
CGW-13 12/12/01 199.08 29.35 0.00 169.73 12,000 154 540 131 1,804 94 --------
CGW-13 02/21/02 199.08 37.50 0.00 161.58 16,000 36 569 102 2,201 157 --------
CGW-13 05/15/02 199.08 26.04 0.00 173.04 12,000 6 290 89 1,800 84 --------
CGW-13 09/05/02 199.08 34.05 0.00 165.03 12,000 4 240 50 1,400 72 --------
CGW-13 11/21/02 199.08 37.92 0.00 161.16 14,000 7 330 130 2,500 130 --------
CGW-13 02/11/03 199.08 41.71 0.25 157.56 --------------------
CGW-13 03/06/03 199.08 42.68 0.22 156.57 --------------------
CGW-13 04/15/03 199.08 43.91 0.37 155.45 --------------------
CGW-13 05/21/03 199.08 42.65 0.00 156.43 --------------------
CGW-13 06/17/03 199.08 41.83 0.00 157.25 --------------------
CGW-13 08/06/03 199.08 40.30 0.00 158.78 28,000 11 580 290 4,600 380 --------
CGW-13 09/25/03 199.08 40.22 0.00 158.86 --------------------
CGW-13 11/19/03 199.08 37.81 0.00 161.27 20,000 5 210 190 3,200 250 --------
CGW-13 02/19/04 199.08 42.75 0.00 156.33 22,000 22 260 320 3,800 260 --------
CGW-13 03/10/04 199.08 43.48 0.02 155.62 --------------------
CGW-13 04/12/04 199.08 44.70 0.31 154.61 --------------------
CGW-13 05/11/04 199.08 43.45 0.00 155.63 19,000 11 210 240 2,300 200 --------
CGW-13 06/15/04 199.08 41.11 0.01 157.98 --------------------
CGW-13 07/12/04 199.08 39.59 0.00 159.49 --------------------
211535_Tables Page 12 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
CGW-13 08/16/04 199.08 37.85 0.00 161.23 6,300 <0.5 13 12 370 58 --------
CGW-13 10/06/04 199.08 39.02 0.00 160.06 --------------------
CGW-13 11/11/04 199.08 39.46 0.00 159.62 11,000 4 46 79 1,400 180 --------
CGW-13 02/02/05 199.08 43.50 0.00 155.58 26,000 5 7 120 1,400 290 --------
CGW-13 03/17/05 199.08 45.29 0.00 153.79 --------------------
CGW-13 05/09/05 199.08 45.65 0.00 153.43 26,000 4 5 58 220 180 --------
CGW-13 08/16/05 199.08 36.63 0.00 162.45 4,000 4 3 5 150 46 --------
CGW-13 11/17/05 199.08 30.69 0.00 168.39 4,300 13 3 13 240 36 --------
CGW-13 02/21/06 199.08 39.90 0.00 159.18 --------------------
CGW-13 05/08/06 199.08 41.22 0.00 157.86 --------------------
CGW-13 02/15/07 199.08 43.31 0.00 155.77 --------------------
CGW-13 07/09/07 199.08 44.10 0.00 154.98 --------------------
CGW-13 10/10/07 199.08 --------------------------
DGW-14 12/11/98 200.72 40.42 0.00 160.30 <20 <1 <2 <2 <2 ----------
DGW-14 02/05/99 200.72 42.81 0.00 157.91 37 3.3 7.4 <2 6 <4 --------
DGW-14 05/05/99 200.72 45.18 0.00 155.54 <20 <1 <2 <2 <2 <4 --------
DGW-14 08/02/99 200.72 38.07 0.00 162.65 <20 <1 <2 <2 <2 <4 --------
DGW-14 11/02/99 200.72 32.27 0.00 168.45 <20 <1 <2 <2 <2 <4 --------
DGW-14 02/02/00 200.72 43.90 0.00 156.82 --------------------
DGW-14 05/02/00 200.72 41.30 0.00 159.42 --------------------
DGW-14 08/03/00 200.72 31.00 0.00 169.72 --------------------
DGW-14 11/13/00 200.72 43.00 0.00 157.72 --------------------
DGW-14 02/21/01 200.72 41.30 0.00 159.42 --------------------
DGW-14 05/30/01 200.72 28.63 0.00 172.09 --------------------
DGW-14 08/23/01 200.72 30.75 0.00 169.97 --------------------
DGW-14 12/12/01 200.72 --------------------------
DGW-14 02/21/02 200.72 --------------------------
DGW-14 05/15/02 200.72 --------------------------
DGW-14 09/05/02 200.72 33.90 0.00 166.82 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
DGW-14 11/21/02 200.72 39.46 0.00 161.26 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
DGW-14 02/11/03 200.72 43.09 0.00 157.63 --------------------
DGW-14 05/21/03 200.72 44.14 0.00 156.58 <50 <0.5 <0.5 <0.5 <0.5 <1 --------
DGW-14 08/06/03 200.72 41.84 0.00 158.88 --------------------
DGW-14 11/18/03 200.72 39.36 0.00 161.36 --------------------
DGW-14 02/17/04 200.72 44.17 0.00 156.55 --------------------
DGW-14 05/11/04 200.72 45.02 0.00 155.70 --------------------
DGW-14 08/16/04 200.72 39.43 0.00 161.29 --------------------
DGW-14 11/10/04 200.72 41.05 0.00 159.67 --------------------
DGW-14 02/02/05 200.72 45.09 0.00 155.63 --------------------
DGW-14 05/09/05 200.72 47.25 0.00 153.47 --------------------
DGW-14 08/16/05 200.72 37.99 0.00 162.73 --------------------
DGW-14 11/16/05 200.72 31.57 0.00 169.15 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
DGW-14 02/21/06 200.72 41.49 0.00 159.23 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
DGW-14 05/09/06 200.72 42.81 0.00 157.91 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
DGW-14 02/15/07 200.72 44.89 0.00 155.83 --------------------
DGW-14 07/09/07 200.72 45.65 0.00 155.07 --------------------
DGW-14 10/10/07 200.72 --------------------------
DGW-15 12/11/98 195.89 35.81 0.00 160.08 <20 160 210 14 590 ----------
DGW-15 02/05/99 195.89 39.34 0.00 156.55 2,100 79 140E 4 490E 25 --------
DGW-15 05/05/99 195.89 42.16 0.00 153.73 2,000 48 7 <2 240 <4 --------
DGW-15 08/02/99 195.89 33.83 0.00 162.06 24,000 330E 270E <2 470E 90 --------
DGW-15 11/02/99 195.89 30.45 0.00 165.44 13,000 390 4,000 360 7,600 220 --------
DGW-15 02/02/00 195.89 35.73 0.00 160.16 10,000 270 1,300 <200 4,200 <400 --------
DGW-15 05/02/00 195.89 36.87 0.00 159.02 2,300 90 100 14 620 44 --------
DGW-15 08/03/00 195.89 31.95 0.00 163.94 3,200 [3,200]85 [82]97 [87]17 [16]1,000E [1,000E]59 [60]--------
DGW-15 11/13/00 195.89 --------------------------
DGW-15 02/21/01 195.89 36.55 0.00 159.34 4,100 70 13 10 680E 130 --------
DGW-15 05/30/01 195.89 27.11 0.00 168.78 11,000 52 440 <50 2,000 170 --------
DGW-15 08/22/01 195.89 29.81 0.00 166.08 <1,000 <100 540 <100 2,300 100 --------
DGW-15 12/12/01 195.89 28.59 0.00 167.30 3,700 9 92 <5 466 44 --------
DGW-15 02/21/02 195.89 34.51 0.00 161.38 8,700 97 25 36 689 197 --------
DGW-15 05/15/02 195.89 26.64 0.00 169.25 9,100 45 280 1 1,400 110 --------
DGW-15 09/05/02 195.89 31.89 0.00 164.00 6,000 36 11 37 140 110 --------
DGW-15 11/21/02 195.89 34.89 0.00 161.00 2,700 20 7 20 62 44 --------
DGW-15 02/11/03 195.89 38.21 0.00 157.68 1,300 28 45 9 54 7 --------
DGW-15 05/21/03 195.89 42.61 0.00 153.28 2,000 19 5 3 7 4 --------
211535_Tables Page 13 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
DGW-15 08/06/03 195.89 37.15 0.00 158.74 660 7 1 <0.8 1 1 --------
DGW-15 11/18/03 195.89 34.72 0.00 161.17 66 2 <0.5 <0.5 <0.5 <1 --------
DGW-15 02/19/04 195.89 39.42 0.00 156.47 <50 1 <0.5 <0.5 <0.5 <1 --------
DGW-15 05/11/04 195.89 40.28 0.00 155.61 110 3 1 <0.5 2 <1 --------
DGW-15 08/16/04 195.89 34.85 0.00 161.04 <50 1 <0.5 <0.5 <0.5 <1 --------
DGW-15 11/11/04 195.89 36.31 0.00 159.58 <50 1 <0.7 <0.8 1 1 --------
DGW-15 02/02/05 195.89 40.20 0.00 155.69 <50 1 <0.7 <0.8 <0.8 <1 --------
DGW-15 05/09/05 195.89 42.47 0.00 153.42 <50 <0.5 <0.5 <0.5 1 <1.0 --------
DGW-15 08/16/05 195.89 33.78 0.00 162.11 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
DGW-15 11/15/05 195.89 29.56 0.00 166.33 630 1 <0.5 <0.5 6 5 --------
DGW-15 02/21/06 195.89 36.67 0.00 159.22 260 1 <0.5 <0.5 <0.5 6 --------
DGW-15 05/09/06 195.89 38.15 0.00 157.74 <50 <0.5 <0.5 <0.5 1 <1.0 --------
DGW-15 02/15/07 195.89 39.96 0.00 155.93 --------------------
DGW-15 07/09/07 195.89 40.84 0.00 155.05 --------------------
DGW-15 10/11/07 195.89 --------------------------
VM-3 05/21/03 200.08 42.92 0.00 157.16 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
VM-3 05/09/05 200.08 46.75 0.00 153.33 <50 <0.5 <0.5 <0.5 1 <1.0 --------
VM-3 02/21/06 200.08 40.71 0.00 159.37 --------------------
VM-3 05/08/06 200.08 42.41 0.00 157.67 --------------------
VM-3 02/15/07 200.08 --------------------------
VM-3 10/10/07 200.08 --------------------------
VM-4 02/11/03 199.00 41.42 0.00 157.58 31,000 44 1,000 380 5,600 240 --------
VM-4 03/25/03 199.00 42.85 0.12 156.24 --------------------
VM-4 04/15/03 199.00 43.79 0.34 155.47 --------------------
VM-4 05/20/03 199.00 42.61 0.03 156.41 --------------------
VM-4 06/17/03 199.00 41.74 0.00 157.26 --------------------
VM-4 06/25/03 199.00 41.70 0.00 157.30 --------------------
VM-4 07/10/03 199.00 40.70 0.00 158.30 --------------------
VM-4 08/06/03 199.00 40.21 0.00 158.79 --------------------
VM-4 10/23/03 199.00 40.18 0.00 158.82 --------------------
VM-4 11/18/03 199.00 37.72 0.00 161.28 --------------------
VM-4 12/15/03 199.00 39.25 0.00 159.75 --------------------
VM-4 02/17/04 199.00 42.63 0.02 156.39 --------------------
VM-4 03/10/04 199.00 43.44 0.08 155.62 --------------------
VM-4 04/12/04 199.00 44.57 0.28 154.64 --------------------
VM-4 05/06/04 199.00 43.44 0.00 155.56 --------------------
VM-4 05/10/04 199.00 43.34 0.00 155.66 --------------------
VM-4 06/15/04 199.00 41.10 0.00 157.90 --------------------
VM-4 06/17/04 199.00 41.13 0.01 157.88 --------------------
VM-4 07/12/04 199.00 39.61 0.00 159.39 --------------------
VM-4 08/16/04 199.00 37.77 0.00 161.23 --------------------
VM-4 09/08/04 199.00 38.18 0.00 160.82 --------------------
VM-4 10/06/04 199.00 38.89 0.00 160.11 --------------------
VM-4 11/11/04 199.00 39.15 0.00 159.85 --------------------
VM-4 12/14/04 199.00 41.30 0.00 157.70 --------------------
VM-4 02/02/05 199.00 43.38 0.00 155.62 --------------------
VM-4 02/25/05 199.00 45.21 0.26 153.99 --------------------
VM-4 03/17/05 199.00 45.29 0.29 153.93 --------------------
VM-4 03/18/05 199.00 45.13 0.02 153.89 --------------------
VM-4 03/28/05 199.00 45.26 0.02 153.76 --------------------
VM-4 05/09/05 199.00 45.60 0.00 153.40 16,000 7 59 220 3,000 370 --------
VM-4 06/07/05 199.00 44.07 0.00 154.93 --------------------
VM-4 06/17/05 199.00 43.24 0.00 155.76 --------------------
VM-4 06/30/05 199.00 40.00 0.00 159.00 --------------------
VM-4 07/18/05 199.00 37.02 0.00 161.98 --------------------
VM-4 08/15/05 199.00 36.54 0.00 162.46 --------------------
VM-4 10/28/05 199.00 31.61 0.00 167.39 --------------------
VM-4 11/14/05 199.00 30.61 0.00 168.39 --------------------
VM-4 01/26/06 199.00 38.26 0.00 160.74 --------------------
VM-4 02/21/06 199.00 39.65 0.00 159.35 --------------------
VM-4 05/08/06 199.00 41.13 0.00 157.87 --------------------
VM-4 02/15/07 199.00 --------------------------
VM-4 10/10/07 199.00 --------------------------
VM-6 12/12/01 199.66 29.76 0.00 169.90 17,000 962 1,150 284 2,347 183 --------
VM-6 02/21/02 199.66 38.25 0.00 161.41 19,000 27 17 19 265 48 --------
211535_Tables Page 14 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
VM-6 05/15/02 199.66 26.49 0.00 173.17 16,000 310 900 220 2,400 130 --------
VM-6 09/05/02 199.66 34.56 0.00 165.10 18,000 130 120 310 1,100 130 --------
VM-6 11/21/02 199.66 38.48 0.00 161.18 7,100 39 18 130 460 86 --------
VM-6 02/11/03 199.66 42.10 0.00 157.56 2,000 12 6 4 150 26 --------
VM-6 05/21/03 199.66 42.42 0.00 157.24 3,200 5 16 8 93 15 --------
VM-6 08/06/03 199.66 40.87 0.00 158.79 1,400 4 7 3 44 14 --------
VM-6 11/20/03 199.66 38.37 0.00 161.29 1,900 1 5 22 88 24 --------
VM-6 02/18/04 199.66 43.31 0.00 156.35 4,600 8 22 79 280 36 --------
VM-6 05/11/04 199.66 43.99 0.00 155.67 14,000 270 1,800 440 3,000 120 --------
VM-6 08/16/04 199.66 38.56 0.00 161.10 3,900 24 8 36 110 46 --------
VM-6 11/11/04 199.66 40.04 0.00 159.62 2,800 23 3 60 130 41 --------
VM-6 02/02/05 199.66 44.02 0.00 155.64 7,800 20 28 230 620 130 --------
VM-6 05/09/05 199.66 46.21 0.00 153.45 9,300 48 18 86 1,300 180 --------
VM-6 08/16/05 199.66 37.19 0.00 162.47 2,800 35 4 17 110 39 --------
VM-6 11/17/05 199.66 31.12 0.00 168.54 9,500 210 16 140 820 95 --------
VM-6 02/21/06 199.66 40.48 0.00 159.18 --------------------
VM-6 05/08/06 199.66 41.77 0.00 157.89 --------------------
VM-6 02/15/07 199.66 --------------------------
VM-6 10/10/07 199.66 --------------------------
VM-7 05/09/05 196.86 42.77 0.00 154.09 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
VM-7 08/16/05 196.86 34.55 0.00 162.31 <50 <0.5 <0.5 <0.5 <0.5 <1.0 --------
VM-7 02/21/06 196.86 37.35 0.00 159.51 --------------------
VM-7 05/08/06 196.86 39.35 0.00 157.51 --------------------
VM-7 02/15/07 196.86 --------------------------
VM-7 10/11/07 196.86 --------------------------
ZSW-1 02/05/99 --97.78 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 05/05/99 --101.00 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 08/02/99 --101.00 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 11/05/99 --99.25 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 02/03/00 --101.00 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 05/02/00 --101.00 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 08/03/00 --101.00 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 11/13/00 --95.95 ----<20 <1 <2 <2 <2 <4 --------
ZSW-1 02/21/01 --------<20 <1 <2 <2 <2 <4 --------
ZSW-1 06/21/01 --------<100 <5 <5 <5 <5 <5 --------
ZSW-1 08/22/01 --------<100 12 <5 <5 <5 <5 --------
ZSW-1 12/12/01 --------<100 <5 <5 <5 <5 <5 --------
ZSW-1 02/21/02 --------<100 <5 <5 <5 <5 <5 --------
ZSW-1 05/15/02 --------<50 5 <0.5 <0.5 1 <1.0 --------
ZSW-1 09/05/02 --------<50 3 <0.5 <0.5 <0.5 <1.0 --------
ZSW-1 11/21/02 --------<50 5 <0.5 <0.5 1 <1.0 --------
ZSW-1 02/11/03 --------<50 4 <0.7 <0.8 2 <1.0 --------
ZSW-1 05/21/03 --------<50 6 <0.5 <0.5 2 <1.0 --------
ZSW-1 08/06/03 --------<50 3 <0.7 <0.8 <0.8 <1 --------
ZSW-1 11/19/03 --------<50 3 <0.5 <0.5 2 <1 --------
ZSW-1 02/19/04 --------<50 8 <0.5 <0.5 <0.5 1 --------
ZSW-1 05/11/04 --------<50 3 <0.5 <0.5 2 <1 --------
ZSW-1 08/16/04 --------<50 12 <0.5 <0.5 2 <1 --------
ZSW-1 11/11/04 --------<50 6 <0.7 <0.8 <0.8 <1 --------
ZSW-1 02/02/05 --------<50 21 <0.7 <0.8 1 <1 --------
ZSW-1 05/09/05 --------<50 13 <0.5 <0.5 3 1 --------
ZSW-1 08/16/05 --------<50 11 <0.5 <0.5 <0.5 <1.0 --------
ZSW-1 11/14/05 --------<50 11 <0.5 <0.5 1 <1.0 --------
ZSW-1 02/21/06 ----------------------------
211535_Tables Page 15 of 16
Table C-3a
Historical Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
Well No.Date Well Location
TOC
(ft-RE)
DTW
(feet)
LNAPL
(feet)
GWE
(feet)
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate as
Nitrogen
(µg/L)
Sulfate
(µg/L)
Dissolved Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700Initial Screening Levels
Notes:
Bolded values = concentrations are above the Utah DEQ Initial Screening Level
DTW = Depth to Water NS = Well not sampled/not analyzed
LNAPL = Light non-aqueous phase liquid SPH = Well not sampled due to the presence of separate phase hydrocarbons (SPH)
GWE = Calculated groundwater elevation VOL = Well not sampled due to insufficient volume of water in well
TOC = Top of casing (surveyed to a relative datum; AGW-1 = 200 ft relative elevation)* = Analyzed for Total Iron by Environmental Protection Agency (EPA) Method 6010B, 6010C, 6010D
RE = Relative elevation ** = Analyzed for Nitrate-Nitrite by Environmental Protection Agency (EPA) Method 353.2
D.O. = Dissolved Oxygen J = Estimated Value between the method detection limit (MDL) and reported detection limit (RDL)
TPH-GRO = Total petroleum hydrocarbons, gasoline range B = The same analyte is found in the associated blank.
µg/L = micrograms per liter J3 = The associated batch QC was outside the established quality control range for precision.
mg/L = milligram per liter J5 = The sample matrix interfered with the ability to make any accurate determination; spike value is high.
< = Analyte was not detected above the specified method reporting limit T8 = Sample(s) received past/too close to holding time expiration.
-- = not measured / not analyzed UB = Compound is considered non-detect at the listed value due to associated blank contamination.
[ ] = Duplicate sample
DRY = Well dry during gauging; not sampled
E = Estimated value exceeds the linear working range of the instrument
HC = Hydrocarbon
211535_Tables Page 16 of 16
Table C-3b
Current Groundwater Monitoring and Analytical Data
Chevron Facility No. 211535
19 North Main Street, Teasdale, Utah
TPH-GRO
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethylbenzene
(µg/L)
Total Xylenes
(µg/L)
Naphthalene
(µg/L)
Nitrate-Nitrite
(µg/L)
Sulfate
(µg/L)
Total Iron
(µg/L)
D.O.
(mg/L)
1,000 5 1,000 700 10,000 700
10,000 300 3,000 4,000 10,000 700
AGW-1 11/8/2023 200.00 41.32 0.00 158.68 805 78.9 2.53 J 60.4 3.78 J <5.00 59.0 J 620,000 7,900 0.88
CGW-11 11/8/2023 198.08 69.83 0.00 128.25 39.4 J 0.380 J <0.278 <0.137 <0.174 <1.00 <50.0 1,340,000 800 2.78
CGW-12 11/8/2023 197.00 54.42 0.00 142.58 11,100 [12,300]91.8 [97.5]5.87 [<6.95]266 [229]72.8 [61.6 J]<5.00 [<25.0]<100 [<100]1,350,000 [1,330,000]1,430 [1,550]
0.41
DGW-16 11/8/2023 193.84 85.18 0.00 108.66 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.00 <50.0 1,320,000 352 2.62
FGW-17 11/8/2023 192.34 52.04 0.00 140.30 834 0.530 J <0.278 <0.137 <0.174 <1.00 <50.0 1,330,000 498 0.90
FGW-19 11/8/2023 195.15 -- 0.00 --<31.4 <0.0941 <0.278 <0.137 <0.174 <1.00 5,910 1,350,000 2,370 6.43
FGW-20 11/8/2023 175.26 109.29 0.00 65.97 <31.4 <0.0941 <0.278 <0.137 <0.174 <1.00 9,970 1,110,000 1,090 6.58
Notes:
ID = Identification Analyte by USEPA Method 8015D/GRO
TOC = Top of casing (surveyed to a relative datum; AGW-1 = 200 ft relative elevation) TPH-GRO = Total petroleum hydrocarbons, gasoline range (C6-C12)
RE = Relative elevation Analytes by USPEA Method 8260B
DTW = Depth to Water Benzene
LNAPL = Light non-aqueous phase liquid Toluene
GWE = Calculated groundwater elevation Ethylbenzene
Bold = Concentrations are above the Utah DEQ Initial Screening Level
Total Xylenes
[ ] = Duplicate sample Naphthalene
µg/L = Micrograms per liter Analyte by Wet Chemistry Method 353.2
mg/L = milligram per liter Nitrate-Nitrite
< = Analyte was not detected above the specified method reporting limit Analyte by Wet Chemistry Method 300.0
VOCs = Volatile Organic Compounds Sulfate
D.O. = Dissolved Oxygen Analyte by Method 6010D
MNA = Monitored Natural Attenuation
Total Iron
-- = Not GaugedNot Sampled J = Estimated Value between the method detection limit (MDL) and reported detection limit (RDL)
Tier 1 Screening Criteria
MNA Parameters
GWE
(feet)Date TOC
(ft-RE)
Initial Screening Level
DTW
(feet)
LNAPL
(feet)Well ID
TPH and VOCs
211535_Tables Page 1 of 1
Figures
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FIGURE
TEASDALE MERCANTILE SITE
CHEVRON FACILITY NO. 211535
19 NORTH MAIN STREET
TEASDALE, UTAH
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ABANDONED VAPOR EXTRACTION WELL
T
W
DGW-16
WAYNE COUNTY RIGHT-OF-WAY
IRRIGATION WELL(NOT IN USE)
INVESTIGATION MONITORING WELL
ZSW-1
VE-1
VM-3
IW-1
ABANDONED VAPOR MONITORING WELL
ABANDONED INJECTION WELL
FSB-7 SOIL BORING
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ELECTRICAL (OVERHEAD)E
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AGW.2 ABANDONED INVESTIGATION
MONITORING WELL
SITE PLAN
C-1
NOTES:
1. BASEMAP DIGITIZED FROM STANTEC BASE MAP
DATE 10/27/16.
2. ALL SITE FEATURES AND LOCATIONS ARE
APPROXIMATE.
3. UST - UNDERGROUND STORAGE TANK.
N
LEGEND:
0
APPROXIMATE SCALE 1 in. = 50 ft.
100'50'
ON-SITE PROPERTY BOUNDARY
E
E
E
E
E
E
E
E
E
E
E
E
E
W
W
W
W
W
W
W
W
W
W
W
T
T
T
T
T
T
T
T
T
T
T
W
W
W
W
W
W
W
W
W
W
W
E E E E E E E E E E E E E E
W W W W W W W W W W
UNPAVED DRIVEWAY
ALLEN
RESIDENCE
0.59 AC.
UNPAVED DRIVEWAY
PODOLOSKI
PROPERTY
0.66 AC.
HANSON
RESIDENCE
1.17 AC.
BLACKHURST
RESIDENCE
1.14 AC.
LYMAN
PROPERTY
.50 AC.
BLACKHURST
PROPERTY
10 AC.
LEATHERWOOD
PROPERTY .72
AC.
DAVIS
PROPERTY
.78 AC.
KING
PROPERTY
.76 AC.
TEASDALE
MERCANTILE
REMEDIATION
SYSTEM
COMPOUND
DAVIS
RESIDENCE
PASSONS
PROPERTY
0.34 AC.
LEAVITT
RESIDENCE
1.00 AC.
EASTHEN FLOOR
BASEMENT
BUSENBASK
RESIDENCE
0.82 AC.
ALIOTTA
RESIDENCE
0.66 AC.
DURFEY
RESIDENCE
0.88 AC.
U.S. FOREST
SERVICE 8
AC.
LUTZ
PROPERTY
0.74 AC.
ANSTETH
PROPERTY
0.74 AC.
TAYLOR
PROPERTY
5.02 AC.
SADERHOLM
RESIDENCE
1.13 AC.
PASSONS
RESIDENCE
0.66 AC.
MENEFEE
RESIDENCE
2.54 AC.
SITE
(BERRY)
D.WILLIAMS
RESIDENCE
C.WILLIAMS
RESIDENCE
MA
I
N

S
T
R
E
E
T
EA
S
T

S
T
R
E
E
T
COMPULSION STREET
NORTH STREET
CGW-11
(128.25)DGW-16
(108.66)
CGW-12
(142.58)
FGW-17
(140.30)
FGW-18
(NM)
AGW-3
(NM)
FGW-19
(NM)
FGW-20
(65.97)
AGW-1
(158.68)
ZSW-1
TEASDALE MERCANTILE SITE
CHEVRON FACILITY NO. 211535
19 NORTH MAIN STREET
TEASDALE, UTAH
FIGURE
C-3
IM
A
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p
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4
:
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:

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A
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I
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A
DGW-16
NOTES:
1. BASEMAP DIGITIZED FROM STANTEC BASE MAP
DATE 10/27/16.
2. ALL SITE FEATURES AND LOCATIONS ARE
APPROXIMATE.
3. UST - UNDERGROUND STORAGE TANK.
N
LEGEND:
0
APPROXIMATE SCALE 1 in. = 50 ft.
100'50'
INVESTIGATION MONITORING WELL
IRRIGATION WELL(NOT IN USE)
RELATIVE GROUNDWATER ELEVATION IN FEET
RELATIVE GROUNDWATER ELEVATION CONTOUR
(25 FEET INTERVAL), DASHED WHERE
INFERRED
APPROXIMATE DIRECTION OF GROUNDWATER
FLOW
APPROXIMATE HYDRAULIC GRADIENT (FEET/FOOT)
NOT MEASURED
150.00
0.256 FT/FT
(158.68)
GROUNDWATER ELEVATION
CONTOUR MAP
NOVEMBER 7, 2023
(NM)
ZSW-1












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
















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















 


 
 


 


 


 


 


 

 



 


 









 


 
 



 


 


 
 
 



 


 


 


 


 


 






MA
I
N

S
T
R
E
E
T
EA
S
T

S
T
R
E
E
T
COMPULSION STREET
NORTH STREET











  
   
   
 

C-4




































































































































































































































































































































































NOTES:
       

       
     
       

      
N
LEGEND:

      



GROUNDWATER ANALYTICAL MAP
NOVEMBER 8, 2023



 
 
78.9
 

 
  
  
 

 
11,100 [12,300]
91.8 [97.5]
  

 
 
 
 

 
 
  
 

 
 
 
 

BOLD


  
   
      
  
    


      
 
    
     
 
 
 

 
 
 
    

 
 
 
 
92.5 ft
PLUME LENGTH
Attachments
Attachment A
Attachment B
Attachment C
Attachment D
Appendix D
SSCL Calculations
[e-mail]
[e-mail]
Eileen Brennan
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[e-mail]
[e-mail]
Eileen Brennan
SSCL Calcs_construction_041424 Page 1 of 4
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SSCL Calculator Prepared for:SSCL Calculator Prepared by:
Site name:
Site address:
Facility ID:
Release ID:
Contact name:
Contact phone:
Contact e-mail:
Site-Specific Cleanup Levels* for Construction Worker Receptors
Air Groundwater Soil
SSCLair SSCLwing SSCLwesp SSCLwamb SSCLs-leach SSCLsesp SSCLsamb SSCLss
Air
Air
Groundwater
Chemical Name (CAS #)
Pr
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r
y

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C
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To
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H
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F
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s
Groundwater SoilSoil
Name:
Company, Agency, other:
Phone:
E-mail:
UST Consultant Cert. #:
Date prepared:
SSCL Calcs_construction_041424 Page 2 of 4
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Site-Specific Cleanup Levels* for Construction Worker Receptors
Air Groundwater Soil
SSCLair SSCLwing SSCLwesp SSCLwamb SSCLs-leach SSCLsesp SSCLsamb SSCLss
Air
Air
Groundwater
Chemical Name (CAS #)
Groundwater SoilSoil
Ad
d
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t
i
o
n
a
l

C
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e
m
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c
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s

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C
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(c
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)
In
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(
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SSCL Calcs_construction_041424 Page 3 of 4
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Site-Specific Cleanup Levels* for Construction Worker Receptors
Air Groundwater Soil
SSCLair SSCLwing SSCLwesp SSCLwamb SSCLs-leach SSCLsesp SSCLsamb SSCLss
Air
Air
Groundwater
Chemical Name (CAS #)
Groundwater SoilSoil
Site-specific Parameters used in Calculations
Parameter Comments
Ad
d
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t
i
o
n
a
l

C
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(n
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-
c
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s
)
Description Value Units
SSCL Calcs_construction_041424 Page 4 of 4
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13:14
Arcadis.Improving quality of life.
Arcadis U.S., Inc.
630 Plaza Drive, Suite 200
Highlands Ranch
Colorado 80129
Phone: [phone]
Fax: [phone]
www.arcadis.com