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r IV KEI-J92-0205.R4 July 6, 1994 Page 4 All samples were analyzed by Sequoia Analytical Laboratory in Concord, California, and were accompanied by properly executed Chain of Custody documentation. All soil and water samples were analyzed for total petroleum hydrocarbons (TPH) as gasoline by EPA method 5030/modified 8015, TPH as diesel by EPA method 3550/modi- fied 8015, and benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA method 8020. The results of the soil analyses are sum- marized in Table 6. The results of the water analyses are summarized in Table 7 . Based on the analytical results of the final soil samples that were collected during the removal of the underground storage tanks, it appeared that the majority of the contaminated soil in the vicinity of the former tank pit had been removed. However, based on the analytical results of the ground water sample that was collected from the tank pit, and in accordance with the guidelines estab- lished by the RWQCB, KEI concluded that further investigative work was necessary at the site. Therefore, in order to comply with the requirements of the RWQCB and the SJCPHS, KEI recommended the reimplementation of monitoring and sampling of the existing monitoring wells at the site. This program was recommended in order to further evaluate the ground water quality, and to determine the prevailing ground water flow direction at the subject site. KEI ' s monthly ground water monitoring and quarterly sampling program began on December 30 , 1992 , and continued until May 28 , 1993 , when the wells were sampled for the last time. Documentation of quarterly ground water sampling and monthly monitoring activi- ties are presented in KEI ' s reports (KEI-P92-0205.QR1 and KEI-P92- 0205.QR2) dated April 2 and July 13 , 1993 . GROUND WATER MONITORING AND SAMPLING A ground water monitoring and sampling program was initiated on July 21, 1988 , by Kleinfelder. Reports on file at KEI indicate that another ground water sampling event was conducted by Kleinfel- der on May 31, 1989. On both occasions, all of the seven Unocal wells were sampled and monitored, and the ground water samples were analyzed for TPH as gasoline, TPH as diesel, and BTEX. The water samples collected on July 21, 1988 , were also analyzed for kerosene, stoddard solvent, and aviation fuel. The water samples collected during the May 31, 1989, sampling event were also analyzed for organic lead, ethylene dibromide, and for EPA method 501 constituents. Records of additional ground water sampling and monitoring conducted at the Unocal site by other consultants are not available to KEI. The analytical results of the water samples collected during the two above noted dates are summarized in the attached Table 2 .