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,�.�aking Underground Fuel Storage Tank gram <br /> III Release and Site Charact r� ization Information (continued) <br /> Maximum Documented Contaminant Concentrations-- Before and After Cleanup <br /> Contaminant Soil (ppm) Water (ppm) Contaminant Soil (ppm) Water (ppm) <br /> Before After Before After Before After Before After <br /> TPH(Gas) 4100 Ethyl-benzene 17 <br /> TPH (Diesel) NT Xylene 150 <br /> Benzene <0.005 <br /> Toluene <0.005 Acetone 780 <br /> MTBE 0.0074 <br /> Comments NOTE: GROUNDWATER RESULTS IN PARTS PER MILLION! <br /> LOW LEVELS OF SOIL CONTAM AT UGT#2 ONLY AT REMOVAL(MAY 1990)OF THP-G=340 ppm, X=39 and E=3.7 <br /> JUST BELOW UGT at -6' bgs. SITE WAS LOW PRIORITY BY LOP EVAL. SEASONAL HIGH GROUNDWATER, <br /> (SPRING 1983) at 45' bgs. HISTORICAL LOW AT 80'+bgs (FALL 1978). ONE GEOPROBE (AUG 18. 1997) TO 64' bgs <br /> REVEALED THPH-G (4100ppm), E=17 ppm, and X=150 ppm at 15' bgs. MTBE =0.0074 ppm at 46' bgs BY 8020 ONLY <br /> AND NO 8260 CONFIRMATION. NO GROUNDWATER at 64' bgs and NO WATER SAMPLE OBTANINED. SOIL at 20', <br /> 25', 46', AND 64' bgs, ALL=ND FOR TPH-G AND BTEX. Unconfirmed Acetone hit of 780 mg/kg at 46' bgs, known to be <br /> seasonal groundwater depth and may be smear from other source. <br /> IV. Closure <br /> Does completed corrective action protect existing beneficial uses per the Regional Board Basin Plan? NO CAP REQ'D <br /> Does completed corrective action protect potential beneficial uses per the Regional Board Basin Plan? N/A <br /> Does corrective action protect public health for current land use? N/A <br /> Site management requirements: NONE <br /> Should corrective action be reviewed if land use changes? NO <br /> Have the Monitoring/Vapor wells been decommissioned? N/A Number Decommissioned: N/A Number retained: 0. <br /> List enforcement actions taken: NORR,04/24/97 <br /> List enforcement actions rescinded: NONE <br /> V. Local Agency Re resentative Data <br /> Name: Donna Heran/ Margaret Lagorio Title: Director of Environmental Health/LOP Supervisor <br /> Signature: Date: _12-7— F <br /> VI. Central Valley Regional Water Quality Control Board RB Notification <br /> Date Submitted to RB: 31 DEC 1997 Response Date: 05 JANUARY 1998 <br /> RB Staff: PAT ANDERSON Response: NFA CONCURRED <br /> Title: Engineer <br /> VII. Additional Comments, Data, etc. <br /> VERTICAL SOIL INVESTIGATTON INDICATED NO CONTAMINATION MIGRATED BELOW 15' bgs TO 20' bgs. THE <br /> SHALLOWEST GROUNDWATER RECORDED IS AT 45' bgs AND SOIL FROM 46,' WAS ND FOR PETROLEUM. <br /> ATTEMPT TO OBTAIN A GROUNDWATER SAMPLE VIA GEOPROBE RESULTED IN REFUSAL IN TIGHT SOILS AT 64'. <br /> EHD DECISION TO SEE IF SOIL IMPACTED BEFORE MORE SOIL INVESTIGATION REQUIRED. EHD DECISION NOT <br /> TO REQUIRE MORE SAMPLING AFTER SOIL DATA INDICATED NO VERTICAL MIGRATION PAST 15'. RP'S <br /> CONSULTANT REQUESTED NFA, EHD CONCURRED. <br /> This document and the related CASE CLOSURE LETTER, shall be retained by the lead agency as part of the official <br /> site file. <br /> MI/01/27/98 <br />