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WKS � _ WOM Quarterly Ground-water Monitoring -�. Beacon Station No. 1-502: Lodi, California December 1, 1138 AGS 86091-6 After initial water levels were measured, samples of ground water from the air--fluid interface were collected for subjective analysis by lowering approximately half the length of ,a clean Teflon bailer past the interface. The bailer was then retrieved and the water sample examined for floating product, sheen, and other subjective evidence of hydrocarbon contamination. No floating product, product sheen, or emulsion was noted in sa from the monitoring wells. Remples sults of these and previous subjective analyses a::e summarized in Table 1. The monitoring wells were purged prior to sampling with an electric submersible pump. Monitoring wells MW-1, MW-2, KW-3, and MW-5 are 4-inch-diameter wells, and 44 to 66 gallons of ground water were removed from each. well MFT-4 is 2-inch- diameter well, and 29 gallons of ground water were removed from it- The purge water .was temporarily stored onsite in 55-gallon Department of Transportation drums, pending removal to Beacon's refinery in Hanford, California, and subsequent treatment in a wastewater separator. After purging, ground-water samples were collected from the wells by lowering the bottom of a clean Teflon bailer to a point approximately 3 feet below the air-water interface. The bailer was then retrieved and the sample w transferred to laboratory-cleaned, 40-milliliter glass vials. Concentrated hydrochloric acid was added as a preservative. Chain of Custody Record was initiated by the field geologist and accompanied the samples to Appl.ie�qGeoSystemsanalytical laboratory in Fremont, California. A copy of that record is attached to this letter report. The samples were analyzed for total Petroleum Environmental Protection Agency Method 015 (modifi hydrocarbons by edg gasoline) anC the volatile hydrocarbonconstituentsbenzene, for ethylbenzane, toluene, and total xylene isomers by EPA Method 602. Applied GeoSystema laboratory is certified by the State of California for these analyses. p Reports are attached to this let Copiesoftthe laboratory Analysis ter The results of the laboratory analyses, which are summarized in Table 2, indicate that the benzene concentration �in ground-water samples collected from monitozing wells 14W-1, MW- and HW-4 exceed; d the maximum level for drinking water recommended by the California. Department of Health Services (DHS) . III general, the concentrations of toluene, ethylbenzene, and total xylRne isomers in "he; samples ,;rom wells MW-1 and MW-2 have increase(! in comparison to the previous analyses but remained levels --for-drinking concentrations of the volatile hydrocarboncommended by the' HS. constituentDs in :;The Applied GeoSVstenms --�