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C:Z <br /> . ASSOCIATES I N C . <br /> Soil Boring Advancement <br /> ATC will advance one soil boring and collect and analyze an estimated two soil samples and one <br /> groundwater sample from the boring. The boring will be located immediately to the south of the <br /> western-most former 1,000-gallon UST (Figure 2). Soil samples previously collected from <br /> borings advanced in this location contained the highest detectable concentrations of petroleum <br /> hydrocarbons. The soil boring will be advanced to first encountered groundwater estimated at <br /> approximately 50 feet bgs, based on San Joaquin County, Flood Control and Water Conservation <br /> District data(SJC, Spring 1998). <br /> The soil boring will be advanced using a hollow stem auger equipped drill rig. Previous <br /> investigations showed that because of tight soils found beneath the site, direct push technology <br /> could not be used to reach groundwater. Drilling will be conducted by a State licensed (C57) <br /> drilling company. A field geologist will be present to log soil samples. Descriptions of soil <br /> types encountered and sample collection intervals will be recorded on a boring log. Soil samples <br /> will be collected at five-foot intervals. Each soil sample will be field screened with a <br /> Photoionization Detection (PID) meter or similar instrument and two soil samples from the <br /> boring, based on field observations (i.e. odor, discoloration, PID readings) and depth, will be <br /> placed in a cooler with ice and submitted for laboratory analysis. <br /> A grab groundwater sample will be collected from the soil boring using a hydropunch <br /> groundwater sampler. Following soil and groundwater sample collection, the boring will be <br /> backfilled with grout to the surface. All drill cuttings will be stored on site in 55-gallon drums <br /> pending laboratory results. <br /> All samples will be immediately placed in a cooler with ice and delivered under chain-of-custody <br /> documentation to a State-certified analytical laboratory. One groundwater and two soil samples <br /> will be analyzed for TPHg by EPA method 8015M, BTEX by EPA method 8020, and fuel <br /> oxygenates by EPA method 8260. <br /> Summary Report <br /> Upon completion of all field activities, a summary report will be prepared for submittal to the <br /> PHS/EHD that will include a description of all field activities and laboratory analytical results. <br /> If the results of this additional work warrant site closure, the summary report will also include <br /> recommendations for site closure. <br /> All work will be performed under the direction of a California Registered Professional Engineer. <br /> A completed Site Safety Plan (SSP) is contained in Attachment 1 and a Quality Control/Quality <br /> Assurance Plan is contained in Attachment 2. All fieldwork will be completed in accordance <br /> with these plans. <br /> w:1920541reponslwkp-boring.doe 3 <br />