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Mr. Vidal Pedroza <br /> March 23, 2000 <br /> Page 2 of 6 <br /> storage tanks (USTs) are present at the subject site. Two tanks previously contained diesel fuel, <br /> and one tank contained unleaded and leaded gasoline. In addition to the USTs, approximately <br /> 230 feet of product pipeline exists between the tanks and the harbor. The USTs were reportedly <br /> installed in 1981. The tank system reportedly failed a pressure test in 1987 due a problem <br /> associated with shared vent lines. Repairs were made to the system and subsequent pressure <br /> tests were passed. The tanks were removed from service and triple rinsed by Jim Thorpe Oil, <br /> Inc. in December 1998. <br /> 2.2 Hydrogeological Setting <br /> The site is located in southwestern Stockton. Surface water bodies nearest the site are Stockton <br /> Deepwater Channel to the north and Mormon Slough to the west Surface elevation at the site is <br /> approximately ten feet above sea level. <br /> Based on historical information provided by San Joaquin County Flood Control and Water <br /> Conservation District known monitoring wells in the vicinity, groundwater beneath the site was <br /> expected to be encountered at approximately 15 feet below ground surface (bgs) and flow toward <br /> the south away from the Channel. <br /> Groundwater quality in the site vicinity is poor. The subject property is located within the plume <br /> of saline groundwater encroaching from the delta area in an easterly direction. The nearest <br /> monitored production wells to the site contain chloride and total dissolved solids in excess of <br /> MCL's. <br /> 3.0 INVESTIGATIVE PROCEDURES <br /> On January 28, 2000 and February 2, 2000, Sean Garvey of Ground Zero arrived at the site to <br /> supervise the subsurface investigation in the vicinity of the former UST's in accordance with the <br /> approved workplan dated January 3, 2000. Mr. Vidal Pedraza of San Joaquin County Public <br /> Health Services, Underground Storage Tank Unit conducted the site inspection and observed <br /> field activities. <br /> Fisch advanced the borings under the supervision of field geologist Sean Garvey, and project <br /> manager John Lane, a California Registered Geologist. <br /> Fisch utilized a truck mounted Geoprobe 5400 direct push rig to advance the borings and collect <br /> soil samples. Soil samples were collected using a 1 3/4 -inch diameter by 24-inch long core <br /> sampler. The sampler was lined with clear acetate sleeves, affording soil identification and <br /> subjective evaluation for contamination. A flame ionization detector (FID) was used to monitor <br /> the presence of volatile organic compounds in the soil. Soil samples from the borings were <br /> sealed, labeled, and immediately placed in an iced cooler for transport to Argon, a state-certified <br /> analytical laboratory. <br /> A total of 14 soil borings were advanced at the site. Borings SBI through SB6 were advanced in <br /> the vicinity of the USTs. These borings were to be advanced at a 30 degree angle from vertical to <br /> G:1DatalGRotiNDZEIWaterfront\Subsurfsum.doc 2 <br />