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WORK PLAN FOR SITE INVESTIGATION <br /> Countryside Market <br /> 10848 Copperopolis Road <br /> Stockton, CA <br /> 1.0 INTRODUCTION <br /> Upgradient Environmental Consultants (Upgradient) has been retained <br /> by Stockton Mortgage Co. to perform an assessment of soil <br /> contamination at Countryside Market on Copperopolis Road, east of <br /> Stockton, California (Figure 1) . The scope of 'Iwork, described in <br /> Upgradient proposal no. 94151St, is to drill five soil borings in <br /> a circular pattern around the former location of two underground <br /> storage tanks and related fuel dispensers in order to collect soil <br /> samples for laboratory analysis of petroleum hydrocarbons . The <br /> proposal was submitted on November 4, 1994 and signed on August 4, <br /> 1995 . The project is under the Local Oversight Program of San <br /> Joaquin County Environmental Health Divison (EHD) . <br /> 2 .0 BACKGROUND <br /> 2 .1 Previous Site Work <br /> It is our understanding that two 1000-gallon leaded gasoline tanks <br /> were removed from the site in March, 1993 (Figure 2 ) . After <br /> removal, the excavated soil was returned to the tank cavity, but <br /> the site was not re-paved. <br /> Four soil samples were collected from beneTath the tanks and <br /> analyzed for petroleum hydrocarbons in the gasoline range (TPH-g) , <br /> BTEX, ethylene dibromide (EDB) , and total lead. Concentrations of <br /> 770 to 6, 500 mg/kg TPH-g were detected, and BTEX, EDB, and lead <br /> were detected at elevated concentrations in one or more samples . <br /> Because of the elevated concentrations, further assessment of the <br /> extent of contaminated soil will be necessary before the site can <br /> be considered for regulatory closure. <br /> 3 .0 PROPOSED ASSESSMENT <br /> A Mobile Drill B53 rig equipped with 8-inch hollow-stem augers will <br /> be provided by V & W Drilling of Rio Vista, California. We estimate <br /> drilling a total of 200 feet, distributed between five borings . The <br /> exact depth and location of each boring will be determined as <br /> drilling progresses and will depend on field observations . Soil <br /> samples will be collected at 5-foot intervals, screened for the <br /> presence of volatile hydrocarbons using a Photovac Microtip HL-2000 <br /> photo-ionization detector, and described on tke boring log. Augers <br /> will be steam-cleaned between borings and drill cuttings will be <br /> placed on plastic sheeting for future disposa' - <br /> In order to determine the maximum depth of soil contamination, <br /> boring CM-1 will be drilled in the center of he tank excavation. <br />