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MAR 2 3 1992 <br /> GSAGeoStrategies Inc. ENVIRONMENTAL HEALTH <br /> 2140 WEST WINTON AVENUE PERMIT/SERVICES <br /> HAYWARD, CALIFORNIA 94545 (510)352-0800 <br /> March 13, 1992 <br /> San Joaquin County Public Health Services <br /> -I P.O. Box 2009 <br /> J Stockton, California 95201 <br /> Attention: Mr. Michael Collins <br /> Reference: Former UNOCAL Service Station No. 0187 <br /> 437 East Miner Avenue <br /> Stockton, California <br /> Mr. Collins: <br /> As per your request during the telephone conversation on March 11, 1992, <br /> GeoStrategies Inc. (GSI) is submitting this scope of work for approval to <br /> overexcavate contaminated soil at the above referenced site. The site is <br /> abandoned and currently being demolished by Gettler-Ryan Inc.. During routine <br /> soil sampling witnessed by a SJCPHS representative, a soil sample was collected <br /> approximately 3 feet below grade in the product piping trench near a former <br /> vapor pot (Plate 1). The sample contained TPH-Gasoline at a concentration of <br /> 150 ppm. The contamination appears to be localized around a former vapor pot. <br /> This scope of work will include: 1) excavation of soil from the area of known <br /> contamination, 2) stockpiling excavated soils and sampling for disposal, and 3) <br /> collection of one verification soil sample from the bottom of the excavation. <br /> While overexcavating, soils will be visually inspected and field screened for <br /> possible contamination by a GSI geologist using an organic vapor meter (OVM). <br /> Excavation of soils will continue until field observations and screening of soils <br /> indicates that no further contamination is present. A verification sample will be <br /> collected and analyzed by a State-certified laboratory (Western Environmental <br /> Science and Technology, located in Davis, CA) for TPH-Gasoline according to <br /> EPA Method 8015 (Modified), BTEX according to EPA Method 8020, EDB <br /> according to EPA Method 8240 and total lead by atomic absorption (EPA <br /> Method 7000). Upon receipt of the analytical data, the excavation will be either <br /> deepened and another soil sample collected (if contamination is identified), or <br /> backfilled with clean fill material and compacted. <br /> Soil removed from the excavation will be stockpiled on-site and covered with <br /> visqueen. Soil samples will be collected from the stockpile by GSI according to <br /> SJCPHS guidelines, and analyzed by a State-certified laboratory for TPH- <br /> Gasoline, BTEX, EDB and total lead as required for disposal. <br />