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CAMBRIA <br /> suggesting attenuation, further assessment of the lateral extent of petroleum <br /> hydrocarbons east of the site is warranted <br /> • Borings CPT-2 and CPT-4, which were drilled north of CPT-1 and CPT-3, respectively, <br /> contained significantly lower petroleum hydrocarbon concentrations than CPT-1 and <br /> CPT-3 This data suggests the petroleum hydrocarbon plume extends only a short <br /> distance to the north of the suspected source area <br /> • The deepest groundwater sample from boring CPT-1 contained total petroleum <br /> hydrocarbon as gasoline (TPHg) and benzene at concentrations of 17,500 and 6,700 <br /> parts per billion (ppb), respectively Further assessment of the vertical extent of <br /> petroleum hydrocarbons in the suspected source area is warranted <br /> • Cambria proposes drilling a deeper cone penetrometer testing (CPT) boring (CPT-5) <br /> adjacent to CPT-1 to assess the vertical extent of petroleum hydrocarbons in <br /> groundwater And to assess the downgradient extent of petroleum hydrocarbons in <br /> groundwater we propose a CPT boring (CPT-6) be drilled adjacent to well MW-17 The <br /> proposed boring locations are shown on Figure 2 <br /> • Cambria proposes one boring (CPT-7) drilled west of CPT-1 to determine if there is an <br /> upgradient source of petroleum hydrocarbons that may be contributing to, or responsible <br /> for, the petroleum hydrocarbons found at depth beneath the former Texaco site The <br /> proposed boring location is shown on Figure 2 <br /> Work Tasks <br /> Permits Cambria will obtain a drilling permit from SJCPHS/EHD prior to performing drilling <br /> activities at the site <br /> Site Safety Plan A Site Safety Plan will be prepared for field work <br /> Utility Clearance. Proposed drilling locations will be marked and their locations cleared <br /> through Underground Service Alert prior to drilling <br /> Site Investigation Three CPT borings (CPT-5, CPT-6, and CPT-7) are proposed as shown <br /> . on Figure 2 A Cambria geologist will supervise the drilling, and encountered soils will be <br /> logged continuously using electronic CPT technology All three borings will be advanced to <br /> 1399 2 <br /> r <br />