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TP^(-E 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTH,,..,ACTION REQUESTS AT UNDERGROUND Tom,< SITES
<br /> Site Name and Location: Tony Gonzales Trucking, 1855 Jackson Avenue, Escalon, San Joaquin County (Lustis Case
<br /> 390220)
<br /> Y Distance to production wells for municipal, domestic, A 2008 well survey reported no domestic or supply wells exist
<br /> culture, industry and other uses within 2000 feet of the site. within 1,200 feet of the site.
<br /> Y 1 2. Site maps, to scale, of area impacted showing locations One 1,000-gallon gasoline, and one 10,000-gallon and one
<br /> of any former and existing tank systems, excavation 500-gallon diesel USTs and associated piping/dispensers
<br /> contours and sample locations, boring and monitoring well were removed 3/88. No new USTs were installed.
<br /> elevation contours, gradients, and nearby surface waters,
<br /> buildings, streets, and subsurface utilities;
<br /> Y 3. Figures depicting lithology(cross section), treatment Site lithology consists of clay, silt,and sand to 60 feet, the
<br /> system diagrams; total depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The fate of the excavated soil is not discussed in the
<br /> reports.
<br /> Y5. Monitoring wells remaining on-site, fate, No monitoring wells were installed. Three soil vapor extraction remediation
<br /> wells(VEW-1A, VEW-1 B, and VEW-2) were properly abandoned on 10/10/08
<br /> with staff approval.
<br /> 6. Tabulated results of all groundwater Depth to groundwater was approximately 60 feet below ground surface
<br /> elevations and depths to water, (bgs). The regional downgradient groundwater direction is towards the
<br /> northeast.
<br /> 7. Tabulated results of all sampling In 10/88, confirmation soil concentrations were TPHd, 3,100 mg/kg; toluene,
<br /> and analyses: 49 mg/kg,xylenes, 390 mg/kg;and lead, 51.5 mg/kg. In 11/00,maximum soil
<br /> concentrations were TPHg,31,000 mg/kg; TPHd, 630 mg/kg;benzene, 70 mg/kg;
<br /> Y❑ Detection limits for confirmation toluene, 900 mg/kg; ethybenzene, 800 mg/kg;xylenes, 3,800 mg/kg;and lead,
<br /> sampling 38 mg/kg. In 11/00, maximum grab groundwater concentrations (4/00) were lead,
<br /> 120 ug/L. In 1/08, the groundwater grab sample results were non-detect.
<br /> ❑Y Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in soil and The extent of the identified
<br /> groundwater, and both on-site and off-site: contamination shown in applicable
<br /> reports.
<br /> N]Lateral and ElVertical extent of soil contamination
<br /> FYI Lateral and Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation The required engineered remediation for
<br /> system and the zone of capture attained for the soil and groundwater remediation groundwater was soil vapor extraction.
<br /> system;
<br /> ❑Y 10.Reports/information Unauthorized Release Form QN QMRS
<br /> n Well and boring logs 151 PAR n FRP ❑Y Other, Soil F&T Model,6/07,GW Confirmation and Soil Gas
<br /> Survey,4/08;Site Closure Request, 5/08
<br /> Y 1 11.Best Available Technology(BAT) used or an explanation for not using Removal of USTs, limited SVE, and natural
<br /> BAT, attenuation.
<br /> }, 12. Reasons why background waslis unattainable Limited soil contamination remains on-site.
<br /> BAT
<br /> _Y] 13.Mass balance calculation of substance treated The consultant estimated the amount of residual contamination in soil
<br /> vas 2462 kg(4/02)and 1213 kg(12/07).
<br /> ersus that remaining;
<br /> �, 14. Assumptions, parameters, calculations and The soil gas Region 2 ESL was exceeded for benzene. A J&E model
<br /> model used in risk assessments, and fate and used the benzene value and reported a 10''risk, which is acceptable.
<br /> transport modeling;
<br /> Y 15. Rationale why conditions remaining at site will Soil contamination is limited in extent. Results of confirmation grab
<br /> not adversely impact water quality, health, or other groundwater sampling were non-detect. The 2007 groundwater data
<br /> beneficial uses; and does not show im acts from the USTs to water quality.
<br /> By: j Comments:One 1,000-gallon gasoline,and one 10,000-gallon and one 500-gallon diesel USTs and associated
<br /> piping/dispensers were removed 3/88. No new USTs were installed. In 10/88, confirmation soil sample
<br /> Date: concentrations were TPHd, 3,100 mg/kg; toluene,49 mg/kg,xylenes, 390 mg/kg;and lead, 51.5 mg/kg. In 11/00,
<br /> 12/3/2008 maximum soil borings concentrations were TPHg, 31,000 mg/kg; TPHd, 630 mg/kg;benzene, 70 mg/kg;
<br /> toluene, 900 mg/kg;ethybenzene, 800 mg/kg;xylenes, 3,800 mg/kg;and lead, 38 mg/kg. In 11/00, maximum
<br /> grab groundwater concentrations(4/00) were lead, 120 ug/L. In 1/08, results of confirmation grab groundwater
<br /> sampling were non-detect. No comments were received during public participation. Based upon limited soil
<br /> contamination,no evidence for impacts to groundwater,limited soil vapor threats from residual contamination,
<br /> and no anticipated changes in land use((residential), Regional Board staff recommend closure.
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