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SUMMARY OF BACKGROUND AND HISTORY <br /> This site review and update is a review of the current conditions at the Marley Cooling <br /> Tower Company (MCTC) Stockton plant to determine what further ATSDR actions are <br /> needed. <br /> MCTC is at 150 North Sinclair Avenue in Stockton, San Joaquin County, California (Figure <br /> 1). The site is an active wood fabrication facility. Properties adjacent to MCTC include <br /> Franklin High School, a storage area for a commercial trucking operation, and residential <br /> areas. Access to the site is limited by a fence around the perimeter of the site. The entire <br /> area is paved. <br /> The 30-acre site is divided into two areas designating the North and South Yards. The South <br /> Yard was purchased in 1942 and has been used for milling and fabricating untreated wood <br /> and storing treated wood. Treated wood is no longer stored in the South Yard and a clean- <br /> up program was performed to remove surface contamination. The North Yard was <br /> purchased in 1965; it contains a wood treatment vessel (retort), treated wood storage areas, <br /> and a storm water and groundwater treatment system. Wood was pressure-treated with <br /> chromated copper arsenate from 1966 until 1982, when the treating solution was changed to <br /> acid copper chromate. MCTC has discontinued wood treatment activities and currently sends <br /> all fabricated material outside for treatment. <br /> Soils were contaminated in several locations on site as a result of past wood-treating <br /> activities. Off-site surface soil contamination existed in isolated areas immediately adjacent <br /> to the facility; that contamination has been removed. Contaminated sediments existed in <br /> some of the drainage pipes and ditch culverts; that contamination has been removed. <br /> Subsurface soils beneath the retort pit area on the North Yard contain copper and arsenic to <br /> approximately 15 feet below land surface and hexavalent chromium reaches the groundwater <br /> table at approximately 60 feet below land surface. <br /> The direction of groundwater flow is south to southwest. Groundwater contamination <br /> appears to exist to a depth of approximately 200 feet below land surface. Levels of <br /> chromium in groundwater beneath and dowrgradient of the site have exceeded federal and <br /> state drinking water standards. At least one municipal well and multiple private irrigation <br /> wells have been impacted by the groundwater plume. Public and private water supply wells <br /> in the area are being monitored. <br /> Recent remedial activities included: (1) closure of a storm water retention pond on the North <br /> Yard; (2) construction of groundwater extraction wells and water treatment plant; (3) <br /> installation of a synthetic liner in the bottom of the retort pit; (4) installation of a 6-inch <br /> berm to contain surface runoff; and (5) remediation of South Yard surfaces and removal of <br /> impacted surface soil from residential yards along the perimeter of the South Yard. <br /> The remedial investigation and feasibility study (RI/FS) reports for MCTC were submitted in <br /> 1 <br />