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Kammr - to obtain a sample from the surface of the water in each well. The sample was retrieved and inspected for floating product, sheen, emulsion, color, and clarity. Approximately 3 well volumes of ground water were purged from the wells using a stainless-steel electrical submersible pump. The pump,cables,and hoses were cleaned with a laboratory-grade, non-phosphatic detergent and water before use in each well. The wells were purged until withdrawal was of sufficient duration to result in stabilized pH, temperature, and electrical conductivity of the water, as measured by portable meters calibrated to a standard buffer and conductivity standard. The wells recovered to more than 90 percent of the static water Ievel within 5 minutes of turning off the pump. The ground water purged from the wells was temporarily riorea in 17E, steel, 55-gallon liquid waste drums approved for this use by the Department of Transportation. Before collecting each ground-water sample, the geologist cleaned the Teflon bailer with a laboratory-grade,non-phosphatic detergent and water and rinsed it with tap water and deionized water before each use. Hydrochloric acid is added to the sample vials as a preservative. A sample of the formation water then was collected from the surface of the water in each of the wells with the Teflon bailer and slowly transferred to laboratory-cleaned 40-milliliter glass vials with Teflon-lined lids so that no air bubbles were present. The samples were then labeled and promptly placed in iced storage. Th,e fluids generated during sample purging were directed into type 17E, steel, 55-gallon, liquid waste drums approved for this use by the Department of Transportation. The drums were labeled ,.. and temporarily stored onsite pending disposal_ Reporting Results of Analyses Hydrocarbon constituents in ground-water samples are reported by the laboratory in units of parts �y per billion (ppb). The maximum contaminant levels listed in Title 22 of the California Code of Regulations for benzene,ethylbenzene and total xylene isomers in drinking water are 1.0,680,and 1,750 ppb, respectively, The action level established by the California Department of Health Services for toluene is 100 ppb. To conform with the laboratory reports,we report ground-water chemical data in units of ppb. Ground-Water Well Survey Moldenhauer Engineering Company ('Moldenhauer) of Davis, California, (Registered Civil Engineer No. 17381)surveyed the elevations and positions("x"and"y"lateral coordinates)of the wellheads of monitoring wells MW-1 to INIW-5 on September 21, 1989. Moldenhauer measured the monitoring wells with respect to the City of Stockton bench mark 2S-2 at the intersection of Harding Way and Pacific Avenue. According to Moldenhauer personnel, Bench Mark 2S-2 is referenced to the United States Geodetic Survey with an elevation of 10.33 feet above mean sea level. The elevation of the wells_were_re.ferenced.._to_...within._0.01.-foot_of Bench_.Mark 2S-2,__The.._horizontal_-- ,4,apL*ed 4GeoSystems - - J