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4 <br /> Stantec <br /> February 9,2010 <br /> Kristi Shelton <br /> Page 2 of 6 <br /> Reference: Work Plan for Additional Site Characterization <br /> SITE BACKGROUND <br /> The site is a former general construction yard owned and operated by PG&E. Previous <br /> investigations have focused on delineating chemical impacts to soil and groundwater from <br /> aboveground fuel storage tanks historically used at the site. Investigative and remedial activities <br /> have included several rounds of soil borings, groundwater monitoring, soil gas sampling, and <br /> source area excavation. <br /> Recent discussions and correspondence 'between iPG&E and the RWQCB have focused on <br /> evaluating the site for regulatory case closure. Risk screening calculations performed by Stantec <br /> have determined that residual concentrations of TPH in site soils do not warrant remedial action <br /> based on human health risk. However, in order to mitigate any potential 'nuisance' conditions <br /> caused by the presence of TPH constituents in shallow soils, PG&E intends to excavate site soils to <br /> ten feet below ground surface. . In the December 16, 2009 correspondence and in a subsequent <br /> conference call on January 13, 2010, RWQCB staff expressed concern that the vertical extent of <br /> chemical impact had not been fully defined at the locations of historical soil borings SB-5, SB-7, and <br /> SB-8. The RWQCB requested additional sampling from these area to provide vertical delineation, <br /> and also requested vadose-zone modeling to evaluate the vertical migration potential of TPH over <br /> time. <br /> PROPOSED SCOPE OF WORK <br /> Task 1 —Soil Characterization <br /> Health and Safety Plan <br /> Stantec will update the site-specific health and safety plan in accordance with the Occupational <br /> Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and Emergency <br /> Response" guidelines (29 CFR 1910.120), and the California Occupational Health and Safety <br /> Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines <br /> (CCR Title 8, Section 5192). The HASP will be reviewed by field staff and contractors before <br /> beginning field operations at the site. <br /> Permitting <br /> Stantec will obtain soil boring permits from San Joaquin County Environmental Health Department, <br /> and coordinate for field inspection as necessary. <br /> I:\PG&E\French Camp\2010 Remediation\Work Plans\PGE French Camp_2010 WP_fnl.doc <br />