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C Work Plan for Additional Site Assessment 2 1 7-Eleven Store#21756,853 E.Yosemite Ave.,Manteca,CA October 27,1999 None of the soil samples contained detectable levels of BTEX, TPH-G or TPH-D; soil MTBE levels ranged up to 0.18 milligrams per kilogram (mg/kg), in the northwest corner of the UST pit at a depth of about 14 feet below grade. Based on UST removal findings, the SJCEHD requested additional site assessment(including collection of groundwater samples). Using a truck-mounted hydraulic drill and direct push techniques, soil borings GP-1, GP-2, GP-3, GP-4, and GP-5 (Figure 2) were drilled on June 17, 1999. Soil samples were collected from each borehole using a 2-inch O.D. California split-spoon sampler, lined with three 1.5-inch-diameter by 6-inch-long brass tubes. The sampler was driven 18 inches ahead of the push rods at each sample point at 4-foot intervals starting at 2 feet below grade. One sample tube from each sampling interval was sealed, labeled, and placed on ice in an insulated container for transport under chain-of-custody to a state-certified laboratory for analysis. Each soil sample was analyzed for BTEX and TPH-G by EPA Methods 8015/8020, and for MTBE and other oxygenates using EPA Method 8260. Laboratory analytical data are summarized in Table 1. Benzene and TPH-G were not detected. MTBE was found in only one soil sample(GP-4) at a concentration of 0.167 mg/kg. On June 17, 1999, grab groundwater samples were collected from the base of soil borings GP-1, GP-2, GP-3, GP-4, and GP-5. The groundwater samples were collected using disposable bailers, then transferred to 40-milliliter glass vials filled to zero headspace and acidified to a pH of 2. The samples were sealed using TeflonS-septum caps, labeled, placed on ice in an insulated container, and transported under chain-of-custody to a state-certified laboratory. The groundwater samples were analyzed for BTEX and TPH-G using EPA Methods 8020/modified 8015, and for MTBE, other oxygenates, ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) by EPA Method 8260. Groundwater analytical data collected June 17, 1999, are presented in Table 2 and shown on Figure 2. Samples from locations GP-1, GP-2, GP-4, and GP-5 were non-detectable for all analytes; the sample from boring GP-3 contained benzene at concentrations of 607 pg/L, TPH-G at 32,300 pg/L, MTBE at 46,300 pg/L, and tert-butyl alcohol (TBA) at 7,760 pg/L. TASK 1: SITE-SPECIFIC HEALTH AND SAFETY PLANIPERMITTING A site-specific Health and Safety Plan has been prepared by IT Corporation as required by the Occupational Safety and Health Administration (OSHA) Standard"Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910.120). The document will be reviewed and signed by all IT Corporation personnel and subcontractors performing work at the site. 21756wkp.LTR