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Home My WebLink AboutDERR-2024-004373Facility Information Facility Name:MAVERIK #481 FARR WEST (FORMER #256)Release ID:NBQ Facility Address:1874 W 2700 N FARR WEST, UT 84404 Facility ID:1200533 Notification Date:09/12/2013 Owner Name:MAVERIK, INC.Reporting Party:Mamum Rashid Owner Address:185 SOUTH STATE STREET, STE 800 SALT LAKE CITY, UT 84111 Project Manager:Mark Crim Site Assessment Information a. Contaminant Source Information Cause of Release (if known) Product Released Amount Released (gal) Size (gal) # of USTs Tank Piping Disp Over/Spill Other Comments Gasoline UNK 3-10K Yes Diesel Waste Oil Unknown Other Tank Piping Disp Free Prod Cont Soil Sources Removed:No Yes Yes No No b. Land Use Information Current Land use at the Site:Commercial Surrounding Neighborhood:Commercial (Note: Surrounding land use is Residential if one or more residences share a common property line with the Facility) c. Soil Information Soil Type(s) Depth to Contaminated Soil (feet below land surface): 10-12 CL-Inorganic clays 12' ML-Inorganic silts/fine sands 3' SP-Poorly-graded sands 12-15' Method of Soil Type Identification:Unified Soil Classification d. Groundwater Information Was groundwater encountered?:Yes Thickness of Free Product:NA Depth to groundwater (feet below land surface): 10 Is groundwater impacted at any concentration: Yes Groundwater flow direction:NW Measured Slope direction of surface topography:NW e. Distance from Highest Measured Contaminated Concentrations and Sampling Location to Nearest Potential Receptor Receptors:(Enter distance to each receptor from corresponding sampling location in feet) Distance- Location Distance- Location Water Line:>30 - W-10 Sewer Line:>30 - W-10 Building Desc:Commercial Electrical:>30 - W-10 Natural Gas:>30 - W-10 Other Desc: Building:>30 - W-10 Telephone:>30 - W-10 Property Line >30 - W-10 Storm Drain:>30 - W-10 Other(specify): - Receptors Within 500 feet: Municipal Well:>500 Domestic Well:>500 Irrigation Well:>500 Other: Surface Water(specify type: lake, stream, creek, river, wetland):Dist: >500 Desc: Willard Canal Utah's RBCA Tier 1 Worksheet Printed on: 12/7/2023 12:55:33 PM Facility History - Executive Summary See Supplemental discussion for site history and exceedances of the ISL standard. RBCA Tier 1 Screening Level Evaluation Groundwater(mg/L)Soil(mg/Kg) Constituent ISL/Tier 1 Level Highest Concentration and Sampling Location ISL/Tier 1 Level Highest Concentration and Sampling Location Benzene 0.005/0.30 0.34 W-10 0.20/0.90 0.408 SS-1 UST Closure Toluene 1.0/3.00 <0.012 W-10 9.0/25.0 0.492 SS-1 UST Closure Ethylbenzene 0.7/4.00 0.12 W-10 5.0/23.0 9.28 W-10S West Xylenes 10.0/10.0 <0.012 W-10 142.0/142.0 1.17 SS-1 UST Closure Napthalene 0.70/0.70 0.398 W-10 51.0/51.0 49.3 W-10S West MTBE 0.20/0.20 0.007 W-10 0.30/0.30 0.16 W-10S West TPH-gasoline 1.0/10.0 2.13 W-10 150/1500 998 W-10S West TPH-diesel 1.0/10.0 NA NA 500/5000 NA Oil and Grease/TRPH 10.0/10.0 NA NA 1000/10000 NA Recommended Tier 1 Actions All contaminant concentration levels are below ISLs or below Tier 1 screening levels and no receptors are within the critical distances. Recommendation - No further action. Tier 1 criteria (contaminant concentration and/or distance to receptors) are exceeded at the site. Recommendation - See attached supplemental information worksheet. Evaluation Completed by:Date: DERR Project Manager's Signature Utah's RBCA Tier 1 Worksheet Printed on: 12/7/2023 12:55:33 PM 12-07-2023 SUPPLEMENTAL INFORMATION FOR NO FURTHER ACTION Maverik #481, 1874 West 2700 North, Farr West, Utah Facility Identification No. 1200533, Release ID ‘NBQ’ Facility History and Contaminant Source Elimination and Control In September 2013, a petroleum release was reported to the Division of Environmental Response and Remediation (DERR) based on the results of an underground storage tank (UST) closure. Release ID ‘NBQ’ (NBQ) was assigned to the facility for further review. Site history indicates the facility was developed as a retail gas station in about 1995, with the property formerly being used for agricultural uses. Several petroleum releases have occurred at the site prior to NBQ. On July 1998, a 300-gallon surface spill of gasoline, occurred due improper drop tube connections from a fuel delivery event. Release ID ‘KOS’ was abated and groundwater was observed overtime. No further action (NFA) status was granted to the site in January 2003. In July 2006, Release ID ‘MCO’ was assigned to the site based on an UST overfill event. The release filled up a UST vent line, ran down a dispenser canopy, becoming a 25-gallon surface spill on pavement and was cleaned up within 24 hours. A DERR Internal Closure Memo was signed in September 2006 (see Figure 1: Site Location Map and Figure1B: Aerial Map). NBQ associated with an UST system closure, included removal of all product lines and dispensers and the in - place closure of three, 10,000 gallons USTs. For soil, benzene was above the DERR Initial Screening Level (ISL) standard at two of eight dispenser locations (SS-3 and SS-5) at 3’ below grade (bg), and near the east side of the UST basin (SS-1) at 12’ bg, while total petroleum hydrocarbons gasoline range organics (TPH-GRO) was above the ISL standard at SS-3. Soils beneath the entire dispenser area were excavated down to 7’ bg, with no confirmation samples collected for dispenser locations (SS-3 and SS-5); later investigations captured enough information to consider the area not a concern. Groundwater sampling results at the UST basin (GW-1 and GW- 2) were above the ISL standard for benzene and TPH-GRO; sample (GW-1) also had exceedances of the ISL standard for toluene, ethyl-benzene and xylenes (see Figure 1C: 2013 UST Closure Map, Table 1A: 2013 UST Closure Soil Analytical Results Exceeding the ISL Standard and Table 1B: 2013 UST Closure Groundwater Analytical Results Exceeding the ISL Standard). Numerous site investigations to determine the extent of soil and groundwater contamination began February 2004 and continued through July 2022, with ongoing groundwater monitoring occurring. Standing out from those investigations was the 2014 soil analyses for installed groundwater monitoring well (MW) (W-10) at 12’ bg, on the east side of the former UST basin. It exceeded the ISL standard for benzene, toluene, ethyl-benzene, xylenes and TPH-GRO. Treatment of the source area with persulfates to stimulate chemical oxidation was suggested by Maverik, but never deployed, and no other corrective actions occurred there. The essence of all investigative work, determinations of remaining source areas and demonstrations of a gasoline plume in remission, indicate that sufficient information exists to consider NFA at the site (see Figure 2: Soil Boring and (MW) Sampling Locations Map, Table 1: Groundwater Analytics and Table 2: Soil Analytics). Source Soils Presented and Remaining: Beginning with the UST removal in 2013 soil sampling results showed that dispenser samples (SS-3 and SS-5) at 3’ and UST basin sample (SS-1) at 12’ bg failed the ISL standard. Soil resampling that followed the 2013 soil excavation work at the dispenser area, include soil sample (W-35) from 2017, collected at 12’ bg and near (SS-5); it was below the ISL standard. Regarding (SS-3) no resampling occurred there, but when installed groundwater MWs W-9, W-21 and W-23 surrounding it, had their soil borings monitored, none showed elevated vapor monitor readings, thus no soil samples were collected, per Maverik’s practice. Moreover, ongoing groundwater monitoring overtime from those MWs has shown no impacts above the ISL standard since 2017. Thus, the dispenser area from 2013, its soil contamination and later excavation work, suggest it should not be a part of the remaining contamination at the site. Specific resampling at UST basin sample (SS-1) never occurred, however in 2017, nearby soil sampling from that area, soil samples (W-1s, W-2s, W-3s, W-5s and W-10s) at 12’ bg, were less than the ISL standard, demonstrating no extensive source soils, and with sample (W-10s) considered as a resampling of (W-10). Another soil sampling event to better describe contamination near (W-10) occurred in 2022. The 2022, soil samples (W-10S East and W-10S South) at 12’ bg, were less than the ISL standard, while soil sample (W-10S West) at 13’ bg exceeded the ISL for ethyl-benzene and TPH-GRO. Thus, the presence of gasoline impacted soils near (W-10S West), and in general the east area of the former UST basin (S-1) are noted a source soils above the ISL standard (see Figure 2: Soil Boring and (MW) Sampling Locations Map and Table 2: Soil Analytics). Groundwater Plume Defined and Demonstrations of Attenuation: Groundwater investigations and monitoring has occurred for 8-years. Observations include that groundwater at about 10’ bg, has a gradient of 0.001 ft/ft, and moves to the northwest. A plume of dissolved-phase petroleum, once about 8,400 square feet (sf) in size, has been reduced to approximately1,800 sf. Currently, the plume axis from MW (W-10) on the south to MW (W-29) northwest is about 90’ in length and has a narrow width of about 20’. Both MWs (W-10 and W-29) exceed the ISL standard for benzene, while (W-10) also exceeds the ISL standard for TPH-GRO (see Figure 2: Soil Boring and (MW) Sampling Locations Map and Table 1: Groundwater Analytics). Because the remaining petroleum affected soil and groundwater exceeds the ISL standard and the distance criteria to subgrade electric lines, NBQ needs further review. The recommendation for no further action includes the need for an in-place contamination map at the site and a notification to the Blue Stakes of Utah network, surrounding the site. Current Land Use Currently, Maverik #481 operates as a commercial convenience store with gasoline and diesel sales. Surrounding properties are agricultural fields to the north, municipal streets to the east and south, and a highway on-ramp to I- 15 west of the site. Land use is unlikely to change any time soon. Nature and Extent of Contamination The nature of the contamination is gasoline associated with a leaking UST system closed in 2013, and historic overfill events of the past. The highest level of remaining soil contamination is at the former UST basin, found at sampling locations (SS-1 and W-10S West) at 12 feet bg. An estimated 70 cubic yards of impacted soil exist near the east side of the former UST basin. Remnants of a gasoline plume in attenuation appear to be localized from the east side of the former UST basin MW (W-10) to MW (W-29), some 90’ to the northwest (see Figure 3: Remaining Contamination Above the ISL Standard Map). Impact of Remaining Contamination on Public Health and the Environment Soil-Leaching-to-Groundwater and Groundwater Ingestion Exposure Pathway Soil contaminated by gasoline near the former UST basin has impacted the local water table. A construction or environmental worker at the site is most likely to encounter petroleum-impacted groundwater, i.e., benzene and TPH-GRO, if groundwater is exposed from about 10’ bg. A 500’ radius search for points of diversion was performed using the Utah Division of Water Rights (DWR) database. No municipal nor private water sources exit within 500 feet of the site (see Attachment ‘A’ for DWR Radius Search). Site-Specific Cleanup Levels (SSCLs) and Groundwater Ingestion No SSCLs were determined for the remaining contamination at the site, however various exposure pathways are discussed below. Regarding the ‘Groundwater Ingestion’ pathway, there is no use of the groundwater at the site. Only the construction worker scenario should be considered for potential groundwater ingestion if the groundwater were brought to the surface from about 10’ bg. Vapor-Intrusion-to-Indoor Air Exposure Pathway Vapor intrusion to indoor air is possible, however, there is no building over the impacted area. In a confined space scenario, only the construction worker is at threat to the in-place contamination near the former UST basin. Vapor-Intrusion-to-Outdoor Air Exposure Pathway Vapor intrusion to outdoor air is unlikely, as the area of concern is covered in concrete. The outdoor air exposure scenario could occur if impacted soils are disturbed from 10-12’ bg. Only the construction worker is at threat from the in-place contamination. Surface Soil Exposure Pathway: Dermal Contact, Particulate Inhalation and Ingestion, and Construction Worker Dermal contact, particulate inhalation and ingestion are only possible near the former USTs, if impacted soils are disturbed from 10-12’ bg. Only the construction worker is at threat from the in-place contamination. Other: Exposure Pathways-Utility Lines Soil contamination remaining near the UST basin potentially affecting utility layouts is negligible. Subgrade electric lines that service the existing dispenser islands are shallow and some 30’ north and northwest of the former UST basin. All other utilities such as culinary water, sewer, storm sewer and natural gas are greater than 40’ from the source area, and enter the property near the convenience store. Only the construction worker is at threat to the in-place contamination near the former UST basin (see Attachment B: Site Utility Map). Economic Considerations and Cost-Effectiveness of Cleanup Options Considering the economics of cleanup for this release is one of cost versus threat. NBQ has been defined in its degree and extent, and evidence of natural attenuation is present and ongoing. A new UST system beyond the system closed in 2013, exists and continues to operate without evidence of a new release. Disturbing the in-place contamination that remains from 2013 is unnecessary and would be costly. Technology Available for Cleanup Technologies do exist for further cleanup of the ‘Maverik #481’ release site. Breaking a concrete surface and soil excavation would be possible, as would be soil venting near the former UST basin. But the lack of any on-going threat to public health or the environment, excepting the construction worker, suggests this release of petr oleum be closed of concern. Recommendation for No Further Action It is recommended that the petroleum contamination associated with the ‘Maverik #481’ release be closed of concern and that NFA status be granted to NBQ. The leaking UST system was closed in 2013, and soil and groundwater contamination that remains is contained on Maverik’s property and attenuating. The release has been evaluated, including threats of remaining contamination to public health and the environment. A review of soil and groundwater data, and of sensitive receptors in the area suggests that only under the construction worker scenario, would petroleum contaminated soil or groundwater be encountered at the site. A NFA letter, coupled with a remaining in-place contamination map at the site and a notification to the Blue Stakes of Utah network surrounding the site, should be issued. Figures 11/29/23, 9:16 AM Map https://maps.waterrights.utah.gov/EsriMap/map.asp 1/1 Figure 1: Site Location Map for Maverik #481 Release NBQ 0 0.1 0.2mi N S W E 12/7/23, 8:52 AM Map https://maps.waterrights.utah.gov/EsriMap/map.asp 1/1 Figure 1B: Aerial Map of Release NBQ 0 100 200ft N S W E Figure 1C: 2013 UST Closure Map Figure 3: Remaining Contamination Above the ISL Standard Map Legend: Groundwater > ISL Soil > ISL Tables Maverik #481 Facility ID 1200533, Release NBQ By Mark Crim, P.G., DERR 12-2023 Table 1A: 2013 UST Closure Soil Analytical Results Exceeding the ISL Standard (mg/Kg) Sample Location Depth (feet bg) Date Sampled MTBE Benzene Toluene Ethylbenzene Total Xylenes Naphthalene TPH-GRO TPH-DRO SS-1 12 9-4-2013 <0.024 0.408 0.492 0.127 1.17 0.112 2.39 NA SS-3 3 9-18-2013 <0.126 1.03 0.832 3.85 86.0 <0.005 297 NA SS-5 3 9-18-2013 <0.130 1.05 0.219 1.32 10.7 <0.130 30.1 NA DERR Initial Screening Levels (ISL) 0.3 0.2 9 5 142 51 150 500 RBCA Tier 1 Screening Levels 0.3 0.9 25 23 142 51 1500 5000 Explanation of Abbreviations: mg/Kg = milligrams per kilogram bg = below grade MTBE = methyl tertiary butyl ether TPH-GRO = total petroleum hydrocarbons-gasoline range organics TPH-DRO = total petroleum hydrocarbons-diesel range organics DERR = Division of Environmental Response and Remediation RBCA = Risk-Based Corrective Action Bolded = Exceeds the ISL Standard NA = Not Analyzed Maverik #481 Facility ID 1200533, Release NBQ By Mark Crim, P.G., DERR 12-2023 Table 1B: 2013 UST Closure Groundwater Analytical Results Exceeding the ISL Standard (mg/L) Sample Location Depth to Groundwater (feet bg) Date Sampled MTBE Benzene Toluene Ethylbenzene Total Xylenes Naphthalene TPH-GRO TPH-DRO GW-1 12.0 9-4-2013 0.004 11.7 14.9 1.96 13.2 0.531 42.9 NA GW-2 12.0 9-4-2013 0.089 0.448 0.009 0.008 0.028 2.97 1.01 NA DERR Initial Screening Levels (ISL) 0.2 0.005 1 0.7 10 0.7 1 1 DERR Tier 1 Screening Levels 0.2 0.3 3 10 10 0.7 10 10 Explanation of Abbreviations: mg/L = milligrams per liter bg = below grade MTBE = methyl-tertiary butyl-ether TPH-GRO = total petroleum hydrocarbons-gasoline range organics TPH-DRO = total petroleum hydrocarbons-diesel range organics NA = Not Analyzed Bolded Values > Initial Screening Levels (ISL) Attachments 11/29/23, 9:11 AM Map https://maps.waterrights.utah.gov/EsriMap/map.asp 1/1 Attachment A: Water Rights Map for Maverik #481 Release NBQ 0 100 200ft N S W E Attachment B: Utility Map Legend: Storm and Sanitary Sewer Water Natural Gas GW Plume Soil > ISL