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1.0 Introduction <br /> 1.1 Purpose and Scope <br /> P P <br /> Shaw Environmental (Shaw)was retained by Mr. Jim Parkinson to generate this Work Plan for a <br /> Monitoring Well Installation at the Parkinson's Hammer I-5 Arco, 3250 West Hammer Lane, <br /> Stockton, San Joaquin County, California (Figure 1). This work plan has been prepared in <br /> response to requests from the of the San Joaquin County Public Health Services Environmental <br /> Health Division (EHD) on May 27, 2005 in response to the filing of a Corrective Action Plan <br /> (CAP) for Parkinson's Hammer I-5 Arco, dated October 26, 2004, and a First Quarter <br /> Groundwater Monitoring Report, dated March 23, 2005. <br /> This work plan presents the purpose and methods for the installation of one groundwater <br /> monitoring well to assess the vertical extent of hydrocarbon contamination in the area of cone <br /> penetrometer test boring CPT-3, which was made next to the service station in 2003. Based on <br /> the detection of benzene at 57 feet below surface grade (bsg) in direct push sampling conducted <br /> at location CPT-3 and the CPT-3 boring log, EHD recommended that a monitoring well be <br /> installed and screened in the thin sand layer between 55 and 60 feet bgs to assess vertical and <br /> lateral extent of contamination. The work will be performed in accordance with the state and <br /> r-- <br /> _ county guidelines for monitoring well installations. <br /> 1.2 Background <br /> The site is addressed 3250 West Hammer Lane, in Stockton, San Joaquin County, California <br /> (Figure 1). It is a privately owned Arco-branded service station that has retailed gasoline fuel for <br /> approximately 15 years. Diesel fuel has never been dispensed at the site. Currently, it contains <br /> three 12,000-gallon capacity gasoline underground storage tanks (USTs) and associated product <br /> lines and dispensers. <br /> The followinginformation was taken from the First Quarter 2005 Groundwater Monitoring <br /> Q g <br /> Report: <br /> The station began product line upgrades and remedial activities in January 2000. <br /> • In August 2000, five Geoprobe borings were made by direct push and discrete water <br /> samples were collected. <br /> • Three groundwater monitoring wells were installed in September 2000 at locations <br /> selected based on the Geoprobe® investigation results. Quarterly groundwater <br /> monitoring and sampling was initiated via these wells in September 2000. <br /> • In May and June of 2002, two monitoring wells were installed and a dual phase <br /> extraction(DPE)test was conducted. <br /> SacDP-N.isacDF120051P0188018800401A.5acWPPalkinson.doc 1-1 <br /> 9.6.05 <br />