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Home My WebLink AboutDERR-2025-006032IIHHII E N V I R O N M E N T A L GROUNDWATER MONITORING REPORT Salt Lake City Fleet Management Yard 850 South 300 West Salt Lake City, Utah Facility ID #4000835 Release ID IEQ October 7, 2011 Prepared for: Utah Department of Environmental Quality Division of Environmental Response and Remediation 195 North 1950 West P.O. Box 144840 Salt Lake City, Utah 84114-4840 Prepared by: Reviewed by: Amy B. Findley Utah-Certified Sampler GS1465 Christopher J. Nolan P.G. Utah-Certified UST Consultant (CC118) Project #11U-E7119 Groundwater Monitoring Report Table of Contents IHI Environmental DERR – SLC Fleet Yard Project No. 11U-E7119 TABLE OF CONTENTS 1.0 INTRODUCTION ..............................................................................................................1 1.1 Objectives ..........................................................................................................1 2.0 METHODOLOGY.............................................................................................................1 2.1 Groundwater Monitoring ...................................................................................1 3.0 RESULTS ........................................................................................................................1 3.1 Observations ......................................................................................................1 3.2 Depth to Product/Groundwater and Groundwater Gradient ..............................2 3.3 Groundwater Monitoring Results ......................................................................2 3.4 Quality Assurance/Quality Control ....................................................................3 4.0 CONCLUSIONS ................................................................................................................3 5.0 PROJECT LIMITATIONS .................................................................................................4 FIGURES Figure 1: Site Map and Groundwater Gradient Map TABLES Table 1: Depth-to Water Table Table 2: Summary of Groundwater Analytical Results APPENDIX 1 Laboratory Analytical Report 1.0 INTRODUCTION The Utah Department of Environmental Quality, Division of Environmental Response and Remediation (DERR), retained IHI Environmental (IHI) to conduct one round of groundwater monitoring and reporting at the Salt Lake City Corporation’s Fleet Management Yard site, located at 850 South 300 West, Salt Lake City, Utah. The DERR Facility Identification is 4000835 and the Release Identification is IEQ. 1.1 Objectives The primary objective of this work assignment was to conduct one round of groundwater monitoring of select wells (MW-1, MW-2, MW-3, MW-6, PZ-1, and PZ-2) and generate a report evaluating the current groundwater conditions. 2.0 METHODOLOGY 2.1 Groundwater Monitoring Depth-to-water measurements were collected from the wells using a product/water interface probe. Each sampled well was then purged of approximately three casing volumes, using a peristaltic pump or disposable bailer. The groundwater samples were collected in laboratory- supplied containers following IHI’s Standard Operating Procedures (SOPs), stored in an iced cooler, and transported under proper chain of custody to Enviropro Laboratories, a Utah- certified laboratory. All groundwater samples were analyzed for methyl tert-butyl ether (MTBE), benzene, toluene, ethylbenzene, xylenes, and naphthalene (BTEXN), using EPA Method 8260B, and total petroleum hydrocarbons gasoline-range organics (TPH-GRO), and total petroleum hydrocarbons diesel-range organics (TPH-DRO), using EPA Method 8015B. Purge water from the wells was surface-applied in paved areas and allowed to evaporate. 3.0 RESULTS 3.1 Observations The length of the groundwater column in the monitoring wells evaluated during this event appeared very shallow. Monitoring well MW-1 was destroyed during the tank removal event, and a groundwater sample from PZ-1 was not collected due to a lack of water in the piezometer. The bottom of monitoring well MW-6 appeared to have been silted in and the Groundwater Monitoring Report 1 IHI Environmental DERR – SLC Fleet Yard Project No. 11U-E7119 casing of monitoring well MW-2 was askew as the result of the UST removal. Since the top of casing measuring point of MW-2 had been compromised, the depth-to-water measurement collected from MW-2 was not included in the calculation of groundwater flow direction. 3.2 Depth to Product/Groundwater and Groundwater Gradient The results of the water level/product thickness survey are shown in Table 1. Groundwater flow direction is included on Figure 1 and was calculated to flow toward the southwest; groundwater in the area may have been temporarily influenced by the excavation of the underground storage tanks and dispenser island. Free product was not detected in the monitoring wells accessed. Table 1 Depth-to-Water Well ID TOC Depth to Water Total Depth GW Elevation Depth to Product PZ-1 95.30 4.47 5.73 90.83 nd PZ-2 95.94 8.07 12.21 87.87 nd PZ-3 96.12 8.38 12.23 87.74 nd MW-2 95.54 7.57* 9.19 -- nd MW-3 95.79 7.91 14.83 87.88 nd MW-4 95.56 8.40 15.46 87.16 nd MW-5 95.74 7.88 15.30 87.86 nd MW-6 95.34 7.02 11.86**88.32 nd TOC – Top of casing. Elevation measurements relative to 100 foot benchmark. Depth-to-water measured from the top-of-casing. *casing may be compromised. **Bottom of well may contain silts. nd – not detected. 3.3 Groundwater Monitoring Results Table 2 summarizes groundwater analytical results. A copy of the laboratory analytical report, including chain-of-custody documentation, is included in Appendix 1. Groundwater Monitoring Report 2 IHI Environmental DERR – SLC Fleet Yard Project No. 11U-E7119 Table 2 Groundwater Analytical Results - Petroleum Hydrocarbons (Results are in mg/L – parts per million) Sample ID TPH- GRO TPH- DRO MTBE Benzene Toluene Ethyl benzene Total Xylenes Naph- thalene PZ-2 <0.05 <1 <0.001 <0.001 <0.001 <0.001 <0.003 <0.002 MW-2 <0.05 <1 <0.001 0.004 <0.001 <0.001 <0.003 <0.002 MW-3 2.34 <1 0.002 1.13 0.018 0.004 0.040 0.023 MW-6 <0.05 <1 0.003 0.001 <0.001 <0.001 <0.003 <0.002 ISLs 1 1 0.2 0.005 1 0.7 10 0.7 Tier 1 10 10 0.2 0.3 3 4 10 0.7 ISLs – Utah’s Initial Screening Levels for petroleum hydrocarbons in groundwater. Tier 1 – Utah’s Tier 1 Screening Levels for groundwater. As presented in Table 2, the concentrations of gasoline-range hydrocarbons and benzene detected in MW-3 exceeded the ISL. The concentration of benzene detected in MW-3 additionally exceeded Tier 1 screening levels. No other petroleum hydrocarbon constituents exceeded the ISL. 3.4 Quality Assurance/Quality Control Quality control for the sampling program was provided by using standardized sample collection and handling methods, documenting pertinent field information, and keeping chain-of-custody records, as well as using a Utah-certified laboratory. All sampling procedures followed IHI’s SOPs. The analytical laboratory report indicated that samples were extracted and analyzed within appropriate sample holding times. 4.0 CONCLUSIONS Based on the analytical results, it appears that groundwater impacts above a screening level remain in the area south of the former underground storage tank pit and dispenser islands. The concentrations observed in MW-3 are comparable to the concentrations observed during previous sampling rounds. Lower concentrations of impacts than observed in previous sampling events were observed in MW-2, north of the former tank pit, and in MW-6, to the southeast of the former tank pit. During tank-removal activities, 6,000 gallons of groundwater were pumped from the tank pit; this action may have resulted in the anomalous results observed in MW-2, located within the tank pit. Groundwater Monitoring Report 3 IHI Environmental DERR – SLC Fleet Yard Project No. 11U-E7119 Groundwater Monitoring Report 4 IHI Environmental DERR – SLC Fleet Yard Project No. 11U-E7119 A majority of the monitoring wells IHI observed during this event appeared damaged or compromised. The existing monitoring well network may need to be evaluated post remediation for effectiveness. 5.0 PROJECT LIMITATIONS This Project was performed using, as a minimum, practices consistent with standards acceptable within the industry at this time, and a level of diligence typically exercised by environmental consultants performing similar services. The procedures used attempt to establish a balance between the competing goals of limiting investigative and reporting costs and time, and reducing the uncertainty about unknown conditions. Therefore, because the findings of this report were derived from the scope, costs, time and other limitations, the conclusions should not be construed as a guarantee that all environmental liabilities have been identified and fully evaluated. Where sample collection and testing have been performed, IHI's professional opinions are based in part on the interpretation of data from discrete sampling locations that may not represent conditions at non-sampled locations. IHI assumes no responsibility for omissions or errors resulting from inaccurate information, or data, provided by sources outside of IHI or from omissions or errors in public records. Furthermore, it is emphasized that the final decision on how much risk to accept always remains with the client since IHI is not in a position to fully understand all of the client's needs. Clients with a greater aversion to risk may want to take additional actions while others, with less aversion to risk, may want to take no further action. APPENDIX 1 LABORATORY ANALYTICAL REPORT