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LE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Exxon Mobil RAS#7-3708(Case 1), 2705 Country Club Blvd.,Stockton, San Joaquin County
<br /> (RB#390672)
<br /> Y 1. Disterm to production wells for municipal,domestic, A 2001 sensitive receptor survey reported one inactive
<br /> agriculture, industry and other uses within 2000 feet of the site. CalTrans well(150'),five domestic wells(600',700',800;
<br /> 900'and 1050')to the south,and two domestic wells 750'
<br /> to the northwest of the site.
<br /> 2. Site maps, to scale, of area impacted showing locations of One 6,000-gallon,one 8,000-gallon and one 10,000-gallon
<br /> any former and existing tank systems, excavation contours and gasoline USTs,and one 1,000-gallon waste oil UST were
<br /> sample locations, boring and monitoring well elevation removed 3-94.
<br /> contours,gradients, and nearby surface waters, buildings,
<br /> streets, and subsu face mWes,
<br /> -Y1 3.Figures depicting lithology(cross section), treatment system Site litho/ogy consists of clay,silt and sand to 93, the
<br /> diagrams; I
<br /> total depth investigated.
<br /> Y 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 200 to 762 y excavated soll(Case 1)
<br /> was removed and transported offsite between 1994 and
<br /> 1995;however, the final location of the excavated soil is
<br /> not discussed In the available reports.
<br /> Allsrr►itonngr web remaining on-site,late, Twenty one(21)monitoring wells(MW-1 through MW-21)and two
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 9'bgs to 17'bgs. Groundwater flow
<br /> elevations and depths to water, I direction varied from northeast to southeast.
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports,Including closure report.
<br /> and analyses:
<br /> 0 Detection limits for confirmation
<br /> sampling
<br /> 0 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/s described in the report
<br /> Lateral and FEVertical extent of soil contamination
<br /> MY Lateral and FYI Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not
<br /> system and the zone of capture attained for the soil and groundwater remediation required by the lead agency.
<br /> s stem'
<br /> 10.Reports/information Y Unauthorized Release Form Y QMRs 8191 to 6110(Case 1 and 2)
<br /> 0 Well and boring logs ❑y PAR 0 FRP 0 Other Case 1 Closure Report(4-11)
<br /> Y 11.Best Available Technology(BAT)used or an explanation for not using Soil excavation and natural attenuation.
<br /> BAT•
<br /> 12. Reasons why background wasfs unattainable Minor residual soil and groundwater contamination remains on-site.
<br /> 13.Mass balance calculation of substance treated Mass was not calculated by the Case 1 consultant(see Case 2
<br /> versus that remaining,* checklist)
<br /> 14. Assumptions,parameters, calculations and Consultant states no significant risk exists,and referred to Case 2
<br /> model used in risk assessments, and fate and risk assessment(See Case 2 Checklist)
<br /> transport modeling;
<br /> 15. Rationale why conditions remaining at site will Soil and groundwater contamination reportedly is limited In extent
<br /> not adversely impact water quality, health,or other Land use(commercial)is not expected to change in the foreseeable
<br /> beneficial uses and future.
<br /> By: JLB Comments One 6,000-gallon,one 8,000-gallon and one 10,000-gallon gasoline USTs,and one 1,000-gallon
<br /> waste oil UST were removed 3-94.at the subject site(Casel). Minor residual soil and groundwater
<br /> Date: contamination remains on-site(Case 1). Based upon the limited extent of contamination reported In soil and
<br /> 8/11/2011 groundwater,no foreseeable changes in land use,and minimal risks from soil,soil vapor,and groundwater
<br /> (see Case 2 Checklist),Regional Board staff concur with San Joaquin County's Closure Recommendation.
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