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a s s gn Y2:,,� •�,�.,� s 'a�,9-fix. �- �..n z ,r, g r*�-�+'` �Ar Cr. Jack Fiori WElSSASSOClATES PM 27 May 1987 9 clay components across rhe higher-permeability sands and reduced permeability. This has not impaired our ability to develop or collect water samples from these wells. Following development, water samples were collected from each well for chemical analysis. A sample of the development water was also collected for chemical analysis. Ground water samples were collected in steam-cieanitd bailers, decanted into 40-m1 labeled VOA vials, refrigerated and transported under chain-of-custody forms to BSC for analysis. CHEMICAL RESULTS The water samples from wells MW-1, MW-2 and MW-3 and well development -, water were analyzed for TFHC and BTX. TFHC was determined by Gas Chromatography (GC) using a modified EPA Method 8015 and BTX was determined by EPA Method 602. Detection limits for the analyses are 1 ppm for TFHC and 0.5 parts per billion (ppb) for BTX. TFHC and BTX in ground water from wells MW-1, MW-2, MW-3 and dumpster water were all below detection limits. Analytic results for water samples are presented in Table 2. Chain-of-custody forms and laboratory reports are included in Attachments B and C. respectively. GROUND WATER GRADIENT Top-of-casing (TOC) elevations for each well were surveyed by Nick Clayton of Precision Industries, Stockton, California. The datum elevation for the survey was benchmark #250, elevation 59.06 above mean sea level (msl), located in the sidewalk southwest of the site. The Cap-of-casing elevations for each well are listed in Table 3. Depth to water was measured in each well on 30 January prior to development and again on 18 March. These measurements are tabulated in Table 3 and ground water elevations are plotted on Figures 3 and 4. Figure 3, representing 30 January water levels, shows a gentle gradient to the north/northeast across the site prior to well development. Figure 4,