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Attaclunent 1 <br /> S[a[e of Calrfotmn state Water Resource Control Board <br /> (New 17!46) <br /> Enwonmrntal]'rotechon Agency <br /> Underground Storage Tank Cleanup Fund <br /> 0 CASE REVIEW FORM <br /> Date 10/31/97 LUSTIS File No oversight Agency San Joaquin County <br /> Site Name/Address Unocal#6981 Responsible Parties Address Tosco Marketing Co Telephone No <br /> 4707 Pacific Avenue Tosco/Unocal 2000 Crow Canyon PI (510)277-2311 <br /> Stock-ton California Atte Mr Ed Ralston San Ramon,CA 94583 <br /> L CASE INFORMATION(N/A=Not Applicable) <br /> Tank No Site in Gallons Contents Closed In-Place/Removed? Date <br /> 1 12,000 Gasoline Removed 6/88 <br /> 2 12,000 Gasoline Removed 6/88 <br /> 3 1 12,000 Gasoline Removed 1 6/88 <br /> IL SITE CHARACTERIZATION INFORMATION(GW=groundrs ater) <br /> GW Basm Safi Joaquin Beneficial Uses All Depth to Drinking Water Aquifer 195 feet(top of screens) <br /> Distance to Nearest Mumcipal Supply Well Distance Between Known Shallow GW Contamination&Aquifer <br /> 1,800 feet crossgradient :L 150 feet <br /> GW Highest Depth 35 feet GW lowest Depth 56 feet Well Screen Interval 24 5-72 feet Flow Direction Northeast <br /> Soil Type Silt with sand lenses Maximum Depth Sampled 72 5 feet <br /> III. MAXIMUM DOCUMENTED CONTAMINANT CONCENTRATIONS-Initial and Latest -=Not Reported, ND=Non-Detect <br /> contaminant Soil(mg/kg) Water(pg/L) Contaminant Soil(mg/kg) Water(pg/L) <br /> Initial(Year) Latest(Year) Initial(Year) Latest(Year) Initial(Year) Latest(Year) Itutial(Year) Latest(Year) <br /> 1988 1997 1990 1997 1988 1997 1990 1997 <br /> (Gas) 1,900 -- 12,000 16,000 Ethylbenzene 66 — 21 180 <br /> TPH(Diesel) — _ _ _ Xylenes 330 — 140 390 <br /> Benzene 84 — 1,900 3,900 MtBE _ _ _ <250 <br /> Toluene 110 -- 75 220 Other _ _ _ -- <br /> IV SOIL REMEDIATION <br /> Method Excavation and SVE Duration of Remediation SVE 9/94-Present <br /> V GROUNDWATER REMEDIATION <br /> Method None Duration of Remediation <br /> VL FREE PRODUCT <br /> Was Free Product Encountered? Yes No= Has Free Product Been Totally Recovered? N/A <br /> When Was Free Product Recovery Project Completed? N/A <br /> VII. RECOMMENDED ACTION <br /> Soil Closure Only Yes= No= Case Closure? Yes= No= Solvent Case? Yes Nor---V-1 <br /> Additional Action Required(1 e,additional site assessment,remediation,monitoring) None <br /> VIII. JUSTIFICATION FOR RECOMMENDED ACTION <br /> remediated to de ee practical No evidence of h drocarbon-im acted soil No SPH ever observed in site wells Dissolved hydrocarbon small and <br /> le Nearest water-supply well 1,800 feet crosses adient of site <br /> 3111657AWSTFUN01 XLS (REV BNO/97) <br />