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Mr.Mark Clardy <br /> Page 7 <br /> April 3, 2006 <br /> • the investigation, the areas to be remediated were identified. However, Shell is committed to <br /> ' addressing additional contamination related to the former Shell pipeline should it become <br /> apparent during site grading. <br /> ' Groundwater Protection <br /> As noted previously, a separate document will be prepared to address any required remediation <br /> of groundwater. The rationale for this approach is that groundwater concentrations are most <br /> reliably obtained from monitoring wells,which are not currently present at the site. Earthwork <br /> activities at the site influence the timing of monitoring well installation, as the wells are difficult <br /> ' to protect from damage during earthwork and hinder efficient grading activities. Once the <br /> monitoring wells are installed,the concentrations in groundwater samples collected from the <br /> wells will be compared to water quality objectives(WQOs) established by the RWQCB. If <br /> ' groundwater concentrations exist in excess of the WQOs, an evaluation of residual petroleum <br /> hydrocarbons in soil and the leachible constituents in the soil will be performed. If residual <br /> petroleum hydrocarbons contain leachible constituents that could result in groundwater <br /> ' concentrations in excess of the WQOs, a remedial approach to reducing the leachible <br /> constituents will be developed. The remedial approach will involve in-situ technology, likely an <br /> enhanced bioattenuation approach or an oxidation approach. A detailed plan will be developed <br /> ' at that time. <br /> PRE-FIELD AND FIELD PROCEDURES <br /> The following sections describe SAIC's pre-field and field procedures for collection of soil <br /> samples for pre-profiling soil to the landfill and for leachibility testing. <br /> ' Pre-Field Procedures <br /> SAIC will obtain necessary soil boring permits for the proposed drilling activities from the San <br /> Joaquin County Environmental Health Department(SJCEHD)prior to fieldwork. In addition, <br /> SAIC will provide the SJCEHD with a copy of the existing access agreements between Shell and <br /> the property owners. <br /> ' SAIC will mark the proposed boring locations and the site boundaries with white paint and notify <br /> Underground Service Alert at least 48 hours prior to commencement of any subsurface <br /> fieldwork,as required by law. <br /> In addition, SAIC will utilize low-hazard penetration techniques (hand auger or air knife)for the <br /> first 5 feet to determine the locations of subsurface assets or hazards. <br /> Soil Sampling Procedure <br /> SAIC will contract a California-licensed(C-57)driller to operate truck-mounted GeoProbe <br /> direct-push equipment and advance the proposed shallow boreholes. Soil cores will be obtained <br /> using a core barrel sampler,which is approximately 4 feet long and 2 inches in diameter. The <br /> t core barrel sampler contains a plastic acetate liner that retains a relatively undisturbed soil core <br /> from which soil samples are collected. The soil samples selected for analysis will be cut from <br /> the plastic liners, sealed with Teflon tape and plastic end caps, labeled with identifying <br />