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0 0 <br /> 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 /> 4827.07.1 4 <br />