ARCHIVED REPORTS XR0001747 - Laserfiche WebLink

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en vii-®s® Five soil borings were drilled and soil and ground water samples were collected during site investigation activities performed by Enviros on behalf of Shell in April 1997 Concentrations of Total Purgeable Petroleum Hydrocarbons (TPPH) in soil ranged from none detected (ND) to 890 ppm Concentrations of Total Extractable Petroleum Hydrocarbons (TEPH) in soil ranged from 1 3 ppm to 260 ppm Benzene concentrations in soil ranged from ND to 0 11 ppm Groundwater samples collected from the borings contained TPPH concentrations ranging from ND to 38,000 ppb, TEPH concentrations ranging from 430 to 25,000 ppb, and benzene concentrations ranging from ND to 1900 ppb Historical Depth to Ground Water Based on historical research performed by GCI, the site operated as a service station from 1949 until 1974 Historical depth to water data were obtained from the San Joaquin County Flood Control District Data were not available prior to the early 1970's Based on a map from the fall of 1977, which appears to represent the deepest ground water conditions for available data, depth to water at the site was approximately 55 feet below grade (fbg) Technical Rationale for Proposed Scope of Work • Soil borings and ground water monitoring wells are proposed to delineate the extent of petroleum hydrocarbons in soil and ground water . • Available historical data indicates that ground water has been as deep as 55 fbg since operation of the underground storage tanks • Data from the nearby BP site investigation indicate that ground water flow direction is to the northeast Work Tasks Task 1 Permits and Right-of-Entry Appropriate permits for drilling permits will be obtained from SJCPHS An agreement for right-of-entry has been obtained from Bank of the West, the current owner of the property A copy of this agreement has been attached The drilling permit for on-site work has been completed and forwarded to Gregg Drilling for signature by the licensed C-57 driller They will sign and forward it to SJCPHS A revocable permit/encroachment permit is required from the City of Stockton, and a second drilling permit is required from SJCPHS for the off-site drilling proposed in the Elmwood Avenue right of way The required forms for the revocable permit and encroachment permit were requested from the City of Stockton on September 11, 1997, and again on September 22, 1997 These forms were not received by Enviros as of September 26, 1997, at which time Enviros representatives personally obtained the forms from the City of Stockton They will be submitted to the City of Stockton concurrently with this work plan When the permits are issued, copies will be forwarded to SJCPHS along with a drilling permit application and fees i 96406 2