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ABLE 1 -CHECKLIST,OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Diesel Performance, 2804 E.Fremont St., Stockton, San Joaquin County(RB#390327)
<br /> Y 1. Distance to production wells for municipal, domestic. A 1998 sensitive receptor survey identified seven water
<br /> agriculture, industry and other uses within 2000 feet of the site. supply wells within the search area. The closest well is
<br /> 700'west and the next well is 900'south of the Site.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of In February 1987, one 3,000-gallon gasoline UST was
<br /> any former and existing tank systems, excavation contours and removed.
<br /> sample locations, boring and monitoring well elevation
<br /> contours, gradients, and nearby surface waters, buildings,
<br /> streets, and subsurface utilities;
<br /> Y 3. Figures depicting lithology(cross section), treatment system Site lithology consists of clay,silt, and sand to 65', the
<br /> lagrams'. total depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The fate of the excavated soil is not indicated in the
<br /> available documents.
<br /> :YD 5. Monitoring wells remaining on-site, fate; Seven monitoring wells(MW--1 through MW-7)and three vapor extraction
<br /> Its EW-1 through VEW-3 will be properly abandoned.
<br /> fi. Tabulated results of all groundwater Depth to groundwater varied from 45'to 58'bgs. Groundwater flow
<br /> elevations and depths to water,, direction was towards the southeast. The consultant did not provide a
<br /> groundwater gradient
<br /> T. Tabulated results of all sampling All data adequately tabularized in various reports, including closure report.
<br /> and analyses:
<br /> Y❑ Detection limits for confirmation
<br /> sampling
<br /> 121 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 /> Lateral and Y❑Vertical extent of soil contamination i
<br /> ' Lateral ander``—FI-Ve-Mc-al-egt&nt-of- oundwater',contamination-�j- -
<br /> -9. Zone of influence calculated and assumptions.used for subsurface remediation Soil vapor extraction(SVE)was the
<br /> system and the zone of capture attained for the soil and groundwater remediation active remediation.
<br /> system;
<br /> 10.Reports/information EY Unauthorized Release Form nY QMRs 35 from 12/99 to 2/10
<br /> FY] Well and boring logs 0 PAR FRP ' Y Other Closure;Report(10/10)Soil Gas Report(4/11)
<br /> _YJ 11.Best Available Technology(BAT) used organ explanation for not UST removal, SVE and natural attenuation.
<br /> using BA T,'
<br /> attainable
<br /> Reasons why background walls Minimal residual soil and groundwater contamination remains on-site.
<br /> usin BAT,•
<br /> Y: 13.Mass balance calculation of substance treated The consultant calculated 6,260.79 lbs TPH removed by SVE.
<br /> versus that remaining; Approximately 0A02 lbs MTBE remain in groundwater.
<br /> Y 14. Assumptions, parameters, calculations and The soil gas survey passed the Region 2 ESLs for commercial use.
<br /> model used in risk assessments, and fate and TPHg in soil at 15',and 20'6gs, and at 20'from the building, exceeded
<br /> transport modeling; Region 2.commercial ESLs for direct exposure and gross,
<br /> contamination at depths below normal worker contact. Water quality,
<br /> goals have been reached.
<br /> Y 15. Rationale why conditions remaining at site Soil contamination reportedly is limited in extent. Land use vw
<br /> will not adversely impact water quality, health, or (commercial)is not expected to change in the foreseeable future. Vapor-
<br /> other beneficial uses;and intrusion.risk has been addressed.
<br /> By: JLB Comments:In February 1987, one 3,000-gallon gasoline UST was removed from the subject Site. Based upon
<br /> 35 quarters of groundwater monitoring showing a stable plume that reached water quality goals, the limited
<br /> Date: extent of contamination remaining in soil, no Region 2 ELSs exceeded, no foreseeable changes in land use,
<br /> 6/1/2011 and limited threats from soil, and soil vapor intrusion, Regional Board staff concur with San Joaquin
<br /> CoUntV�s Closure Recommendation
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