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'CENTRAL VALLEEGIONAL WATER QUALIT:CONTROL BOARD <br /> INSPECTION REPORT <br /> 13 April 1989 <br /> DISCHARGER: Marley Cooling Tower Company <br /> LOCATION & COUNTY: Stockton, San Joaquin County <br /> CONTACT(S) : Dave Lieb, Inspection Supervisor <br /> INSPECTION DATE: 29 March 1989 <br /> INSPECTED BY: Robert L. Niblack <br /> ACCOMPANIED BY: Scott Walker and John Tomko of the RWQCB <br /> BACKGROUND <br /> Marley Cooling Tower Company (MCTC) owns and operates a cooling tower fabrication plant. <br /> Lumber used in the construction of cooling towers had been treated on-site with chromated <br /> copper arsenate from 1966 until 1982 when acid copper chromate was substituted. A surface <br /> impoundment was used for the collection of storm water from the wood treatment storage <br /> area. Hazardous levels of chromium, arsenic, and copper accumulated in the soils forming <br /> the unlined surface impoundment. <br /> OBSERVATIONS AND COMMENTS: <br /> This inspection fulfills the requirement set in Section 25208.7 of the Toxic Pits Cleanup <br /> Act (TPCA) that, "The regional board shall make at least one inspection per year of all <br /> facilities with surface impoundments, . . . " <br /> The surface impoundment was completely dry at the time of this inspection. A sump in the <br /> center of the impoundment contains a pump to drain water which may collect in the <br /> impoundment. Several improvements have been made to the impoundment since the last annual <br /> TPCA inspection on 28 April 1988. Improvements include a sprinkler system with lines on <br /> the perimeter and through the center of the impoundment. This system is supposed to <br /> prevent contaminated dust from becoming mobilized in dry windy conditions. A single strand <br /> wire barrier designed to restrict access into the impoundment has been constructed on top <br /> of the dike which forms the impoundment. Although it serves little purpose as a physical <br /> barrier, it is used to support caution notices, and draw attention to the contaminated <br /> area. <br /> MCTC is currently working on phase V of a ground water investigation. At the time of this <br /> inspection, monitoring wells were being completed at a distance of over one mile down <br /> gradient of the facility. According to site assessment reports, the source of most of the <br /> ground water pollutants is the retort (pressure vessel ) pit in which the wood-treating <br /> process is contained, not the "toxic pit" . Ground water contamination occurring as a <br /> result of the storm water pond operation appears to be limited to hexavalent chromium. <br /> The cease discharge requirement of the TPCA has been met at this facility. Although <br /> geological materials with hazardous concentrations of waste constituents remain exposed <br /> to the influx of rainwater, the sump pump can remove any free liquids which run into the <br /> impoundment, and direct the liquid to the on-site water treatment plant. The surface <br />