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California Reanal Water Quality Catrol Board <br /> Central Valley Region b. <br /> Vinton H.Hickox Steven T.Butler,Chair <br /> Secretaryfar Gray Davis <br /> Environmental Sacramento Main Office Governor <br /> Protection Internet Address:http://w .sw eb.ca.gov/mgcb5 <br /> 3443 Routler Road,Suite A,Sacramento,California 95827-3003 <br /> Phone(916)255-3000•FAX(916)255-3015 <br /> 25 August 2000 h0 .?I Nd &� 0 <br /> Mr. Daniel Decker <br /> ContiGroup Companies, Inc. <br /> 277 Park Avenue <br /> New York,NY 10172 <br /> SECOND QUARTER 2000 GROUNDWATER MONITORING REPORTAND WORKPLANFOR <br /> ADDITIONAL SITE CHARACTERIZATION, CONTIGROUP COMPANIES,INC., <br /> 9504 S. HARLAN ROAD, FRENCH CAMP, SAN JOAQUIN COUNTY <br /> I have reviewed the 23 June 2000 Second Quarter 2000 Groundwater Monitoring Report and Work Plan <br /> for Additional Site Characterization (Work Plan) submitted by Metcalf& Eddy, Inc. (M&E) for the <br /> ContiGroup Companies, Inc. (CGCI)French Camp Elevator facility(site). I have the following <br /> comments regarding this Work Plan: <br /> 1. M&E incorrectly states that adequate soil analytical data have already been collected. Since a <br /> source for the contaminants to groundwater has not yet been identified, CGCI needs to conduct an <br /> alternative, reconnaissance soil investigation that may have a higher likelihood of identifying the <br /> source area than discrete soil sampling, such as a soil vapor survey. <br /> 2. The Work Plan lists several incorrect water quality objectives. Based on the California <br /> Environmental Protection Agency Cancer Potency Factor as a Drinking Water Level (one-in-a- <br /> million cancer risk), the water quality objectives for tetrachloroethene (PCE), methylene chloride <br /> (dichloromethane; DCM), dibromochloromethane(DBCM), and chloroform are 0.69 µg/1, <br /> 2.5 µg/1, 0.37 µg/1, and 1.1 µg/1, respectively. For chloroform, we typically set the cleanup goal to <br /> the less conservative drinking water health advisory(also a one-in-a-million cancer risk) set by the <br /> U.S. EPA of 6 µg/1. Additionally, based on the drinking water health advisory set by the U.S. <br /> EPA, the water quality objective for bromoform is 4 µg/1. <br /> 3. Several of the proposed wells will be installed in deeper water-bearing units. Monitoring wells <br /> installed in deeper water-bearing units without isolating upper zones may act as a pollution conduit <br /> between the zones. CGCI needs to isolate wells installed in deeper units from the more shallow <br /> water-bearing units by completing the wells with outer conductor casing(s) (dual completion <br /> wells). CGCI needs to submit proposed monitoring well construction details for the dual <br /> completion wells prior to beginning this field investigation. <br /> 4. M&E proposes to collect a limited number of soil samples to evaluate lithologic conditions during <br /> well installation, but did not propose chemical analysis of the soil samples. Since cone <br /> penetrometer(CPT) data have not been collected near the proposed wells, CGCI needs to obtain <br /> California Environmental Protection Agency <br /> ea Recycled Paper <br />