SITE INFORMATION AND CORRESPONDENCE

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632 S . EI Dorado, Stockton Page 2 " samples from EW1 and VW1 must be analyzed for the CAM 17 metals . This facility has operated as a plating shop for a number of years and metals may be present in the groundwater. If groundwater extraction is implemented as a corrective action for this site, the concentration of metals in the groundwater must be known to evaluate disposal alternatives for the extracted groundwater. EHD and CVRWQCB have concluded that dual phase extraction (groundwater and soil vapor) is the best available technology for cleanup at this site. Gasoline contamination appears localized in soil and groundwater near the former UST. The lateral and vertical extent of groundwater contamination is defined and appears stable. EHD and CVRWQCB recommend dual phase remediation in the source area utilizing existing wells EW1 and VW1 . Installation of additional groundwater extraction wells as proposed by AGE in the FRP dated April 23, 2000, is not approved at this time. A site conceptual model (SCM) should be prepared for this site using existing data that shows the relationship between contaminants, retention/transport media, and receptors . The SCM is a written description supported by maps, geological cross-sections, tables, and diagrams that provide information about the site. The SCM should include the following: 1 . Local and regional plan view maps showing location of sources, extent of contamination (i .e. , an interpretive drawing - not merely a plot of laboratory results) , direction and rate of groundwater flow, and locations of receptors. "Receptors" include, but are not limited to, all supply wells within 2000 feet of the source area; 2 . Cross-sections showing subsurface geologic features, depth of groundwater, man-made conduits, monitoring well construction, and an interpretive drawing of the vertical extent of soil contamination;