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Work Plan - Fortner Unocal Station No 0187 <br /> October 9, 1997 <br /> Task 1 3 Wellhead Survey <br /> Following installation, GSI will have the well casing elevation surveyed to MSL by a California <br /> licensed surveyor Horizontal coordinates of the well will also be obtained <br /> Task 1 4 Well Development and Sampling <br /> GSI will develop the newly installed well after being allowed to stand a minimum of 72 hours <br /> following completion A groundwater sample will be collected from the well upon completion of <br /> development Groundwater removed from well during development will be stored at the site in <br /> properly labelled drums pending disposal The newly installed groundwater monitoring well will be <br /> included in the quarterly monitoring and sampling program for the site Groundwater samples will <br /> be analyzed as described in Task 1 5 <br /> Task 1 5 Laboratory Analyses <br /> GSI will submit samples for chemical analysis by a California-certified Hazardous Material Testing <br /> Laboratory Soil samples will be analyzed for Total Petroleum Hydrocarbons as gasoline (TPHg) by <br /> EPA Method 8015, and for Benzene, Toluene, Ethylbenzene, and total Xylenes (BTEX) The <br /> stockpiled drill cuttings will also be analyzed for total lead Groundwater samples will be analyzed <br /> for TPHg, BTEX, and methyl tert-butyl ether (MTBE) by EPA Method 8020 <br /> Task 1 6 Report Preparation <br /> Following receipt and analysis of all data, a report will be prepared which summarizes the procedures <br /> and findings associated with the installation of the offsite well This report will be submitted to <br /> Unocal for their use and distribution <br /> TASK 2 REMEDIATION FEASIBILITY STUDY <br /> SJCPHS requested in their letter mailed on January 25, 1996 that a work plan to initiate soil remediation <br /> feasibility testing be submitted by April 30, 1996 At Unocal's request, GSI prepared a Soil Remediation <br /> Feasibility Study Work Plan in April 1996 that proposed a six month soil vapor extraction test to evaluate <br /> the feasibility of this technology The summary of site conditions contained in the Work Plan indicated <br /> that soil beneath the site consisted predominantly of clay to a depth of 40 feet bgs This clayey unit <br /> overlies a sandy unit to a depth of at least 55 feet bgs <br /> Soil beneath the original UST pit and dispenser island D-4 (borings U-C and U-D) contained residual <br /> petroleum hydrocarbons to depths of at least 45 feet bgs Highest concentrations of TPHg were detected <br /> in boring U-L at 45 feet bgs (19,000 ppm) and U-P at 35 feet (20,000 ppm) Concentrations of residual <br /> TPHg in soil samples collected from depths less than 35 feet bgs did not contain concentrations higher <br /> than 5,300 ppm Benzene was not detected at concentrations higher than 1 2 ppm in soil samples <br /> collected above 35 feet bgs <br /> 482707-1 4 <br />