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George's Service <br /> Remedial Action Work Plan <br /> Project No.425.2 <br /> June 30,2011 <br /> 2. INTRODUCTION <br /> 2.1. Purpose and Goal <br /> The purpose of this Remedial Action Plan is to provide details on the selected alternative for <br /> a proposed remedial action to address the residual contaminated soil and groundwater at the <br /> site, in compliance with the provisions of Section 25356.1 of the California Health and <br /> Safety Code. <br /> The goal of this Remedial Action is to remove the contaminants in the subsurface beneath the <br /> parcel by in-situ remedial methods, to allow the site to be considered for low-risk closure, to <br /> achieve aquifer restoration and reduce risk to human health and the environment. <br /> 2.2. Site History <br /> The Site, located at the intersection of Highway 33 and Durham Ferry Road, has been owned <br /> and operated by George and Mei Teranishi since the 1940's as an automobile repair facility <br /> and market. Gasoline was sold at the Site until 1990, when the tanks were removed. <br /> The Site has been undergoing site characterization work commencing 1995 by Del-Tech <br /> Geotechnical Support Services. Three monitoring wells were installed in early 1995 and <br /> elevated levels of petroleum hydrocarbons were detected on the northern and western sides <br /> of the property. <br /> In January of 1997 Geological Technics Inc. (GTI) contracted with Mr. and Mrs.Teranishi to <br /> provide additional site characterization work regarding the definition of the lateral and <br /> vertical extent of petroleum hydrocarbons in the soil and groundwater. In early April 1997, <br /> GTI installed five new water-table monitoring wells and one intermediate depth, discretely <br /> screened, monitoring well. In mid 1998, GTI installed two additional intermediate depths, <br /> discretely screened, monitoring wells and one deep discretely screened, monitoring well. <br /> Quarterly groundwater monitoring reports have been submitted throughout the project. <br /> In late July 2001, GTI and Del Tech performed a limited soil excavation at the Site and <br /> removed approximately 500 cubic yards of contaminated soil. Analytical data shows that <br /> approximately 4,900 pounds of TPH-G were removed from the Site. At the end of October <br /> 2001, the stockpiled soil was transported and disposed of at Forward Landfill. GTI <br /> submitted a report on the soil excavation activities on January 28, 2002. <br /> During the backfill of the excavation, the County inspector reviewed the work in progress <br /> and discussed the issue of the residual contamination left under the building, around the <br /> monitoring wells, and under Durham Ferry Road. It was concluded that piping should be <br /> installed for use in a bio-venting project that could extract at a slow rate the vapors emitted <br /> from the residual contamination. Subsequently, two pipes were installed to allow for the <br /> operation of a low flow bio-venting/vapor extraction system in and around the excavation. <br /> Geological hechnics lnc. 2 <br /> 4252 RAP.docx <br />