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Department of Toxic Substances Control <br /> Alan C.Lloyd, Ph.D. 8800 Cal Center Drive Arnold Schwarzenegger <br /> Agency Secretary Sacramento, California 95826-3200 Governor <br /> Cal/EPA <br /> REC0dF= <br /> August 26, 2005 pill, 2 9 2005 <br /> ENVIRONMENT HEALTH <br /> SERVICES <br /> Mr. Marshall Cloud <br /> Defense Logistics Agency <br /> Defense Distribution Depot San Joaquin, Sharpe Site <br /> Post Office Box 960001 <br /> Stockton, California 95296-0250 <br /> COMMENTS ON NATURAL ATTENUATION (NA) AND TREATMENT TECHNOLOGY <br /> EVALUATIONS REPORT FOR DEFENSE DISTRIBUTION DEPOT, SHARPE SITE, <br /> LATHROP, CALIFORNIA <br /> Dear Mr. Cloud: <br /> The Department of Toxic Substances Control (DTSC) received the above-mentioned <br /> document on July 22, 2005. The report discusses the need to collect soil and ground <br /> water data that will be used to select a possible ground water volatile organic compound <br /> treatment technology. The possible treatment technologies presented in the report <br /> include monitored natural attenuation, aerobic cometabolic oxidation (air and methane <br /> injection), in-situ chemical oxidation (sodium persulfate, potassium permanganate, or <br /> hydrogen peroxide), in-situ oxidation/air sparging w/ ozone, EHCTM, iron filing wall <br /> acting as a permeable reactive barrier, and enhanced anaerobic reductive <br /> dechlorination through lactate injection. DTSC has reviewed the report and has the <br /> following comments: <br /> General Comment: <br /> 1) DTSC recommends that the proposed investigation of remedial alternatives <br /> follow the United States Environmental Protection Agency's (US EPA) protocol <br /> for the collection and analysis of data to evaluate Monitored Natural Attenuation <br /> with US EPA OSWER Directive 9200.4-17P, in addition to the US EPA's <br /> September 1998 guidance document entitled: "Technical Protocol for Evaluating <br /> Natural Attenuation of Chlorinated Solvents in Ground Water." DTSC expects <br /> the Final NA Evaluation Report to include a discussion of the revised site <br /> conceptual model using the new data, including a thorough discussion of <br /> contaminant sources, ground water flow paths and contaminant phase <br /> distribution. <br /> ® Printed on Recycled Paper <br />