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tion water. The purged water was contained on-site, in secured <br /> 55-gallon drums. Since no contaminants were detected in the <br /> r samples, the water produced during development and purging does <br /> not require treatment or special handling. The water will be <br /> utilized on-site for dust control. Water sample collection and <br /> Preservation was in accordance with WaterWork ' s QA/QC Plan. <br /> Bailers with bottom emptying devices to reduce volatilization <br /> , were used. The water samples were analyzed by Applied Analytical <br /> and by Sequoia Analytical for QA/QC purposes for BTEX and TPHD by <br /> appropriate EPA and DHS methodologies. A sample from MWl was not <br /> collected since it had been covered by asphalt paving and could <br /> not be located. <br /> All site activities involving potential contact with hazardous <br /> materials (i.e. gasoline contaminated soils) were conducted in <br /> accordance with WaterWork's Health and Safety Plan. The field <br /> investigation was conducted under the direct supervision of Nora <br /> H. Kataoka, California Registered Civil Engineer No. 38322. <br /> 3.3 Subsurface Conditions <br /> ~^ Soils encountered at the site during excavation consisted pri- <br /> marily of lean and fat clays to 9.5 feet below grade, the maximum <br /> � depth explored. Hydrocarbon odors and soil discoloration were <br /> noted from six feet below grade to the top of the groundwater <br /> table. <br /> Sails encountered during drilling of MW2 and MW3 consisted mainly <br /> Of fine to medium, poorly-graded sands. Laboratory analyses of <br /> the soil samples showed no detectable concentrations of BTEX and <br /> TPH as diesel. Lab results are uummarized on Table 1 . Data <br /> sheets, chain-of-custody forms QA/QC documentation are included <br /> in Appendix IV. <br /> 3.4 Groundwater conditions <br /> - Groundwater was encountered in the excavation at a depth of 9.5 f <br /> feet below grade. During tank removal and soil excavation, <br /> evidence of petroleum contamination was observed in saturated <br /> soils below 9. 5 feet (discoloration, odor) . Product sheen was <br /> observed in standing water within the excavation, but was most <br /> likely due to contact with contaminated soils above the water <br /> table. <br /> Groundwater was encountered during drilling of monitoring wells <br /> MW2 and MW3 at 10 feet. during groundwater monitoring, 24 hours <br /> after drilling, the static water table was measured at approxi- <br /> mately 8 feet. <br /> Because monitoring well MW1 could not be accessed (covered by <br /> asphalt) the gradient could nor be established on-site. However, <br /> WaterWork currently monitors the uppermost saturated zone at <br /> three Tracy sites within a one-mile radius of the subject site. <br /> OF 5 <br />