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w <br /> 1.0 Introduction <br /> rr Corporation (IT) was retained to prepare an interim groundwater treatment plan (plan) to <br /> remediate low levels of total petroleum hydrocarbons (TPH) as diesel detected in the <br /> groundwater at the Van den Bergh Foods Company underground storage tank site (Site Code <br /> 22073), located in Stockton, California (Figure 1). <br /> The selected plan for the site includes application of a patented technology using a <br /> magnesium peroxide compound that, when exposed to moisture, releases dissolved oxygen to <br /> the environment (groundwater) at a slow rate. The increased dissolved oxygen has been <br /> demonstrated to increase the rate of intrinsic bioremediation of hydrocarbons in groundwater. <br /> 1.1 Facility Background <br /> The Van den Bergh Foods Company facility is located at 1400 Waterloo Road, Stockton, <br /> California. The facility has been used for commercial food processing for over 30 years, and <br /> is located on the flat terrain of California's Central Valley. The soils underlying the facility <br /> consist largely of silts and clays with interbeds of sands. A five to ten feet thick sand unit is <br /> encountered between depths of 45 feet and 55 feet. The site groundwater has historically <br /> been observed at depths varying between 51.5 feet and 79.85 feet, and flows at a shallow <br /> horizontal gradient (0.001 to 0.006 ft/ft). <br /> 1.2 Site History <br /> On May 26, 1984, a 1000-gallon gasoline tank, a 550-gallon Stoddard (petroleum) solvent <br /> tank, and a 550-gallon diesel tank were removed from a common excavation by American <br /> Environmental Management Corporation. Analytical results of native soil samples collected <br /> from the bottom of the tank pit yielded concentrations of TPH as diesel and chlorinated <br /> organic compounds. The tank excavation was subsequently backfilled. <br /> Subsequent investigative and corrective actions implemented at the site have included: <br /> • Drilling of three soil borings to 30 feet (R-1, R-2, and R-3) by Stauffer in 1987. <br /> • Installation of three monitoring wells (MW-1 to 63 feet, MW-2 to 64.5 feet, and <br /> MW-3 to 65 feet) by Roy F. Weston, Inc. in October 1988. <br /> MZ(07-10-9WVDBF196-0017 1 <br />