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Levine-Fricke-Recon DRAFT analyzed the samples for VOCs (Table 5). Hazardous Substances have not been detected in the eight samples collected from these wells. As described in Section 3.2, based on the direction of groundwater flow observed at the Site, municipal well COS #11 is the nearest municipal supply well located downgradient from the Site. According to COS DMU, well COS #11 is scheduled to be sampled for VOC analysis in the first quarter of 1999. LFR has recommended sampling well COS #11 in early 1997, as described in Section 4. 3.3.2.3 Monitoring Wells From 1990 to 1996, monitoring wells installed at or adjacent to the Chevron and Exxon service stations have been periodically sampled for VOCs (Table 5). Certain Hazardous Substances have been detected in groundwater samples collected from five of the six existing Chevron monitoring wells. Groundwater samples were also collected from monitoring well CHMW-1 before it was abandoned. Chevron monitoring wells are located downgradient from known or suspected sources of detected Hazardous Substances at the Site. PCE was detected at concentrations up to 10,000 µg/1 in samples collected from these wells. The most recent groundwater samples were collected from these wells in November 1996 (LFR 1997b). Hazardous Substances have not been detected in the 4 samples collected from existing Exxon monitoring wells that have been analyzed for VOCs. The detection limit for samples collected from these wells is 3 µg/1. The most recent groundwater samples were collected from these wells in April 1995. 3.4 Abandonment Procedures for Former LVMD Wells In 1992,wells LVMD #1, LVMD #2, and LVMD #6 were abandoned by SIC DPW because of the presence of VOCs in groundwater samples collected from these wells (SIC DPW 1992). Analytical results for groundwater samples collected by SIC DPW from these wells indicated that concentrations of detected Hazardous Substances exceeded the respective MCLs, as described in Section 3.3 of this report (Table 5). Well LVMD #4 was abandoned by SIC DPW because of the presence of elevated concentrations of iron and manganese detected in groundwater samples collected by SIC DPW (SIC DPW 1992). The evaluation of the abandonment procedures for former LVMD wells was based on a review of well construction data, lithologic logs, video logs, destruction plans and specifications, and record drawings as described in Section 2.4. The plans and specifications, prepared by SIC DPW, include a background section that describes the original well construction, well video survey results, and well repair, as applicable, for each of the wells (Appendix F). These plans also describe the specific methods that were required to prepare the well before abandonment including perforating the casing, pressure grouting the casing, and restoring the ground surface following well abandonment. Although these plans provide the details of the proposed abandonment Page 14 4IIIWELL.AMJ:AMJ