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Delta 3330 Data Drive Suite 100 Rancho Cordova, CA 95670 . Environmental 9161638-2085 Consultants,Inc. FAX:9161638-8385 January 4, 1994 K.LCEIVLD Ms. Marla Guensler FEB 2 2 1994 Exxon Company, U.S.A. Post Office Box 4032 ENVIRONMENTAL HEALTH Concord, California 94524-2032 PERMIT/SERVICES Subject: Quarterly Ground Water Monitoring Report, Fourth Quarter 1993 Exxon Retail Station No. 7-3330 3128 West Benjamin Holt Drive Stockton, California Delta Project No. 40-93-810 Dear Ms. Guenter: Delta Environmental Consultants, Inc. (Delta),. has been authorized by Exxon Company, U.S.A. (Exxon), to conduct quarterly ground water monitoring at Exxon Retail Station No. 7-3330, located at 3128 West Benjamin Holt Drive, Stockton, California. This letter report presents the results of quarterly ground water monitoring and sampling conducted on November 18, 1993. The .i location of the site is shown in Figure 1 and site features are illustrated in Figure 2. All work conducted at the site by Delta was performed in accordance with the field methods and procedures described in Enclosure A. Around Water Table Elevations, Flow Direction, and Hydraulic Gradient Ground water table elevations were measured in each of the four existing monitoring wells at the site on November 18, 1993. . Depths to ground water in the monitoring wells ranged from 12.44 to 13.00 feet below the tops of the well casings. The ground water table elevations have decreased approximately 1h foot since the previous monitoring event in September 1993. Ground water table measurements are presented in Table 1. A water table contour map constructed from the ground water table elevations recorded on November 18, 1993, is included as Figure 3. The water table contours illustrated in Figure 3 indicate that ground water flowed toward the north-northeast with a hydraulic gradient of approximately 0.001. Subjective_Analis No liquid-phase petroleum hydrocarbons or hydrocarbon sheens were present in the wells during the November 1993 site visit. Analytical Results Ground water samples collected from monitoring wells MW-3, MW-4, MW-5, and MW-6, on November 18, 1993, were submitted to a California-certified laboratory for analysis of benzene, toluene, ethylbenzene, total xylenes, and total petroleum hydrocarbons as gasoline. Analytical test results are summarized in Table 2. Ground water samples collected from monitoring wells MW-3, MW-4, MW-5, and MW-6 did not contain detectable concentrations of petroleum hydrocarbons with Delta Delivers Solutions