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Soil and Groundwater Sampling Summary Soil and groundwater samples were collected from the exploratory bonngs and uncased boreholes, and from groundwater monitoring wells during the project The sampling procedures are discussed in the assessment and monitoring reports submitted to PHS-EHD The historic data summanes are attached in the summary tables The soil and quarterly groundwater samples from December, 1996 forward were analyzed using EPA Methods 5030/ 8015 and 602 for Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene, Toluene, Ethylbenzene and Xylene (BTEX) and fuel oxygenates including Methyl-tert- butyl-ether (MTBE) and Volatile Organic Compounds (VOC) by EPA Method 8260 (see attached Table 4 for historic data and detection limits in table footnotes) Very low concentrations of Tetrachloroethene (PCE), Trichloroethene (TCE) and cis-1,2- Dlchloroethene have been observed in upgradient well MW-2 and "side-gradient" well MW-3 VOC compounds have not been observed at MW-4 These VOC compounds were occasionally observed at concentrations dust above the detection hrmt The presence of VOC at MW-3 could be suggestive of another contaminant plume (having first arrived at upgradient well MW-2) This contaminant group is suggestive of a dry cleaner source, and not from an on-site source 2000-foot Well Search Summary The attached well search identified the reported wells within the 2000-foot radius of the site The nearest City of Tracy wells (about 800-feet and 1,000 feet respectively) are side-gradient to the site, and the nearest downgradxent well is at the extreme edge of the search There have been no reports of which Wright is aware by the City (the purveyor of drinking water) of drinking water problems caused by petroleum contaminants to their wells Further, the site shallow aquifer lies stratigraphically above the underlying pumping aquifer The well data information gathered by Wright is from readily available published and unpubhshed State and local agency sources, and addressed the PHS EHD request The well location information is as complete as the official records are for these wells The lack of other information on some logs (pertaining to location depth, length of seals, lithology logging, etc ) arises from the incomplete form completion, filing or form submittal to agencies in the past Based upon these data, the wells plotted in the well search are not present along Imes of surmised contarnmant flow, and these wells occur beyond the furthest mapped extent of the M & M dissolved plume Page 3