ARCHIVED REPORTS XR0010259 - Laserfiche WebLink

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_ _----- Former _ __Former Discovery Chevrolet June 27, 1995 TPHg and benzene were detected in wells MW-1 (400 and 120 ppb, respectively) and MW-2 100 and 37 m respectively). TPHg, BTEX TPHd and O&G were not detected in well � ppm, P Y)• g� MW-3. These data have been used to construct a TPHg/Benzene/TPHd Concentration Map (Figure 4). Disposition of Soil Cuttings Soil cuttings generated during the installation of wells MW-1 through MW-3 were stockpiled at the subject site pending disposal. Based on our conversation with Mr. Sasson (SJCEHD) and Mr. John Solomon, service manager for Tracy Chevrolet, it is our understanding that a portion of the stockpile soil washed away during the heavy rains of the first quarter, 1995. Mr. Solomon indicated that the remainder of the stockpiled soil was moved to an unpaved area 50 feet west of the body shop building and immediately north of the paving, and was used to fill in a low stop in a parking area. At the request of Mr. Sasson, one soil sample (SS-1) was collected from this area on April 26, 1995,.by G-R to assess whether residual hydrocarbons remained in the soil. Mr. Sasson was present to observe sample collection. This sample was analyzed for TPHg and BTEX. Petroleum hydrocarbons were not detected in this sample. Soil sampling procedures are presented in Appendix A. . A copy of the analytical laboratory report and chain-of-custody form are included in Appendix D. f Disposition of Wel] Purge Water Purge water generated during the installation,'development, and first quarter 1995 sampling of groundwater monitoring wells MW-1 through MW-3 was transported from the site for disposal on April 24, 1995. Five drums of water were transported by Integrated Wastestream Management (IWM) of Milpitas, California, to the Seaport Environmental disposal facility in Redwood City, California. A copy of the IWM Non-Hazardous Water Transport Form is included in Appendix E. DISCUSSION AND CONCLUSIONS During the second quarter 1995 depth-to-groundwater measurements rose approximately 0.03. to 0.04 feet (wells MW_1 and MW-2, respectively) and decreased approximately 0.01 feet (well MW-3) from water levels measured during the first quarter 1995. During the second quarter 1995 groundwater appeared to flow toward the north-northwest under a gradient of 0.003. These data appear generally consistent with monitoring data from first quarter 1995. TPHg and benzene were detected upgradient (well MW-1) and downgradient (well MW-2) of the former gasoline USTs. Petroleum hydrocarbons were not detected downgradient of the former waste oil UST (well MW-3). O&G has not been detected in groundwater samples from well MW-3 for three consecutive sampling events. Hydrocarbon concentrations from first quarter to second quarter 1995 deceased in wells MW-1 and MW-2. - 8146.02-2 .4