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I <br /> I <br /> 3. PROPOSED INVESTIGATION <br /> ;;The objective of the current investigation is to confirm the absence of petroleum hydrocarbons in <br /> the subsurface soil and groundwater at the site by collecting soil samples at discrete locations and <br /> depths where elevated petroleum hydrocarbon concentrations were detected in previous <br /> investigations and to collect grab groundwater samples at each location. This work will be <br /> `performed in accordance with the guidelines set forth in the Tri-Regional Board Staff <br /> 'Recommendations for Preliminary Evaluation and Investigation of Underground Tank Sites and <br /> Appendix B: Requests for Closure, 10 August 1990 and 1 March 1994,and requirements of the <br /> I;SJCEHDand the California Regional Water Quality Control Board, Central Valley Region <br /> :(RWQCB). <br /> 3.1 SITE HEALTH AND SAFETY PLAN AND PERMITS <br /> A site-specific Health and Safety Plan will be prepared by EA as required by the Occupational <br /> ;Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and <br /> + Emergency Response" guidelines (29 CFR 1910.120). The document will be reviewed by EA <br /> f•� personnel;and subcontractors prior to working at the site. A copy of the Site Health and Safety <br /> Plan will be kept at the work site and will be available for reference by appropriate parties during <br /> the work.,An EA geologist will act as the Site Safety Officer. <br /> Prior to performing field activities,EA will obtain all drilling permits and notify the SJCEHD <br /> 72 hours prior to the commencement of the proposed work. <br /> 3.2 DRILLING OF CONFIRMATORY SOIL BORINGS <br /> Three confirmatory soil borings will be drilled adjacent to the UST basin and one boring <br /> downgradient to the southeast of the USTs, at the locations shown in Figure 3. The proposed <br /> confirmatory soil boring locations were chosen so as to verify the remediation of the former UST f <br /> basin which was the primary source of contamination and to verify the absence of a continuing <br /> impact in the downgradient direction. The four proposed borings will be drilled using a direct <br /> push method to a maximum depth of 46 feet bgs. Boring advancement and sampling will be <br /> performed by a C-57 licensed driller, using a Geoprobe drill rig equipped with 1.5-inch-diameter <br /> continuous core casing. The field procedures for dritIling and soil sampling are presented in <br /> I•� <br /> Appendix A. <br /> 3.3 ''SOIL AND GROUNDWATER SAMPLING <br /> The direct-push method of drilling will provide nearly continuous soil samples for subsurface <br /> materials assessment. Soil samples will be collected at 5-foot intervals at a minimum. The <br /> samples will be collected in clean 6-inch-long brass or stainless steel sampling tubes by driving <br /> an 18-inch!'to 36-inch-long sampler into undisturbed soil. The contents of the tubes will be <br /> examined for soil characteristics and screened with an organic vapor analyzer(OVA)to <br /> determine the relative content of volatile organic compounds (VOCs). <br />�•I+ <br /> ! <br /> 70137.W?W$.CLO5�WP.WPO <br /> 11 f <br /> i <br /> r � <br />