ARCHIVED REPORTS XR0000577 - Laserfiche WebLink

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Chevron Products Company 5 Chevron Service Station 9-0557 139 South Center Street Stockton,CA March 21,2001 . CONCLUSIONS According to the CPT data collected during this assessment, the site hydrogeology consists of mainly fine-grained sediments with intermittent sandy interbeds. Based on both current and historical soil analytical data, it appears that the majority of hydrocarbons in soil are in the vicinity of the former gasoline USTs (SB-4, MW-9, and HP-4). Hydrocarbons have impacted groundwater in the vicinity of the former gasoline USTs (MW-1, MW-2, and MW-9), and have migrated downgradient to the area of MW- 5 and MW-7. Non-detectable to low concentrations of hydrocarbons in wells MW-3, MW-4, and MW-6 suggest that the hydrocarbon plume in groundwater has been defined in the areas north, northwest, and west of the former USTs. Low concentrations of hydrocarbons and oxygenates were reported in a grab groundwater sample from HP-2 at 57 feet bgs. No other detections of hydrocarbons or oxygenates were reported in the offsite borings HP-1 through HP-3, located to the cast and south of the site. The most downgradient well, MW-8, has been non-detect for hydrocarbons and oxygenates for the last five quarters. Data collected during this investigation suggests that the contaminant plume has been defined to low to non-detect levels. RECOMENDATION SECOR recommends that the quarterly monitoring and sampling program be continued to verify that the plume is delineated. If there are any questions regarding the contents of this site assessment, please call us at (916) 861-0400. Sincerely, SECOR International Incorporated Rog Hoffmore Associate Geologist AED GF�(o a GREG $AACt_AY "{ fIVO.5266 Greg Barclay (5, Registered Geologist _VX Qt's RG 6260 CA��F° I:1Chevron1905571REPORTS\MtBE Eva[\MtBE evat.doc