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So►L� k Environmental Technology Inc product nor sheen was noticed in any of the monitoring wells Dedicated,/ bailers were used for sampling activities at each of the wells, in order to eliminate possible cross examination The six water samples collected were stored in an ice chest at 4 degrees Celsius Appropriate chain of custody was prepared prior to transporting to a State ' certified laboratory Del Mar Analytical, Irvine, CA performed the laboratory analyses All the water samples were analyzed for Total Petroleum Hydrocarbons (TPH) as gasoline (Volatile Fuel Hydrocarbons) and Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) following EPA Methods 8015/8020 ' The test data are presented in Table 2 All laboratory analytical results including QA/QC are enclosed with this letter report Table 2 also includes the historical data for wells MW-1 through MW-6 The groundwater level observations (Table 1) indicated a consistent increase of approximately 3 4 to 3 5 feet during the reporting period (9/28/94 and 12/l/94) It should be noted be that fluctuation in groundwater level is a common occurrence in the Stockton area as reported by Applied Consultants data April 9, 1994 Figure 2 presents the groundwater contour map It appears that theeneral groundwater now direction is towards the west During the period 9/94 and 12/94, TPH (gasoline) concentrations in MW-1, MW-2, MW-4, MW-5 and MW-6 haveme uced from 21,000, 2,300, 12,000, 600 and 3,400 to 5,300, 1, 100, 2,200, 420, and 1,200 respectively TPH concentrations in MW-3 has increased from 88 to 500 A TPH concentration contour map is presented in Figure 3 Similar trends of decrease in Benzene concentration at the wells MW-1, MW-2, MW-4, MW-5, and MW-6 were reported except at MW-3 where the benzene concentration has increased from 8 9 to 97 µg/l Based on these and past observations, SO_TA pro oses further delineation of the ro water contamination lume as re uired b San Joa uin County SOTA as submitted a workplan detailing the proposed additional site assessment on or before November 29, 1994, and awaiting county review comments and �- approval Should there be any questions regarding this transmittal please contact me or .� Larry Busch at (619) 485-8100 s Sincerely, SO A Environmental Technology, Inc , �� `° '��'*' ,� ��"., Dakshana Murthy, Ph D , P E F {' ' Project Manager r_ M31 4- cc Steve Gilbert, U-Haul International, Phoenix, AZ �'