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<br /> (ABLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Den's Auto Repair, 308 S. EI Dorado St., Stockton, San Joaquin County(RB#390889)
<br /> 7Y 1. Distance to production wells for municipal, A 2006 sensitive receptor survey reported 1 domestic water supply
<br /> domestic, agriculture, industry and other uses well within 2,000'of the Site.A 500'reconnaissance search could not
<br /> within 2000 feet of the site. locate the domestic well,400'north,and the property was reported on
<br /> municipal water. The well if resent,is not threatened by the release.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of any former and In 4/95, one 5,000-gallon, one
<br /> existing tank systems, excavation contours and sample locations, boring and 7,000-gallon, and one 8,000-gallon
<br /> monitoring well elevation contours, gradients, and nearby surface waters, gasoline USTs and one 500-gallon waste
<br /> buildings, streets, and subsurface utilities; oil UST were removed.
<br /> Y 3. Figures depicting lithology(cross section), treatment Site lithology consists of clay,silt,and sand to 125, the total
<br /> system diagrams; depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal The fate of the excavated soil was not discussed in the available
<br /> (quantity); reports.
<br /> y 5. Monitoring wells Thirteen(13)monitoring wells(MW-1A through MW-3A,MW-1B through MW-3B, and MW-4 through
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<br /> remaining on-site, fate; MW-10)and two(2)remediation wells(OB-1 and OB-2)will be properly destroyed prior to closure.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 21'bgs to 31'bgs. Groundwater flow
<br /> elevations and depths to water, direction varied from southeast to northeast. Groundwater gradient varied
<br /> from 0.0001 to 0.004 ft/ft.
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports.
<br /> and analyses:
<br /> Y❑ Detection limits for confirmation
<br /> sampling
<br /> �Y Lead analyses
<br /> LY J 8. Concentration contours of contaminants found and those remaining in The extent of the identified contamination is
<br /> soil and groundwater, and both on-site and off-site: described in the available reports.
<br /> ElLateral and FY]Vertical extent of soil contamination
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface Ozone injection(OI)was the engineered
<br /> remediation system and the zone of capture attained for the soil and remediation.
<br /> groundwater remediation system;
<br /> 10.Reports/information QY Unauthorized Release Form MY QMRs(36)9-97 to 2-11
<br /> EY Well and boring logs 10 PAR 10 FRP nY Other Closure Report, 12112
<br /> removal, Ol,and natural attenuation.
<br /> Y 11.Best Available Technology(BAT) used or an explanation USTs
<br /> for not usin BAT;
<br /> UY 12. Reasons why background wasrs Residual soil and groundwater contamination remains.
<br /> ttainable using BAT,
<br /> Y 13.Mass balance calculation of substance Approximately 1,500 lbs TPH remain in soil and 3.34 lbs TPH remain in
<br /> treated versus that remainin ; groundwater.
<br /> Y 14. Assumptions, parameters, calculations A soil vapor survey was not required by the regulatory agency.Soil meets
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<br /> and model used in risk assessments, and fate SWRCB low risk closure policy for commercial use down to 15'bgs,
<br /> and transport modeling; which is below construction worker depths. HHRA did not show risk from
<br /> soil. Consultant states site does not represent a significant risk.
<br /> Y 15. Rationale why conditions remaining at site Soil and groundwater contamination reportedly are limited in extent.Land
<br /> will not adversely impact water quality, health, use(commercial)is not expected to change in the foreseeable future.
<br /> or other beneficial uses;and Consultant could not estimate when WQGs will be reached. Groundwater
<br /> plume is stable.
<br /> By: J Comments:In 4/95, one 5,000-gallon, one 7,000-gallon,and one 8,000-gallon gasoline USTs and one
<br /> 500-gallon waste oil UST were removed at the subject site. Residual soil and groundwater contamination
<br /> Date: remains.Based upon the limited extent of contamination reported in soil and groundwater,a stable plume,
<br /> 3/12/2013 no foreseeable changes in future land use(commercial), and minimal risks from groundwater,soil vapor and
<br /> soil, Regional Board staff concur with San Joaquin County's Closure Recommendation.
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