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WE GE- i "O WESTERN GEG-ENGINEERS direction as shown on figure 11A of the July 25, 1988 report. Also evident is the continual drop in the ground water elevation that averaged 1.11 feet per well through the monitoring period (May 7 thr u August 9, 1988 or 0.01 feet per da ) P y (see table 1 and figures 3an 4 and Appendix S) . Water samples obtained from the monitor wells during the July 5 and August 9, ,. 1988 site visits where preserved and chain-of - custody hand delivered to Eureka Laboratory. Eureka ran EPA method 8015, Total Petroleum Hydrocarbons, (TPH) and EPA method 602, Aromatic Volatile Organics -Benzene, Toluene, Xylenes and Ethyl Benzene, (BTX&E). The chemical results show that monitor wells 2 and 3 are still none detectable for TPH and BTX&E. Monitor well 1 shows a decrease in TPH as compared to the June 1, 1988 sample (4.0 ppm in June to none detectable in July and August). The BTX&E has decreased to below the Department of Health Services DOHS actions levels set for drinking water as of (DOHS) g II May 3, 1988 (benzene 0.7 ppb, toluene 620 ppb and xylenes 100 ppb). See table I 2 and appendix A. CONCLiTSIONS A shallow ground water has been measured at depths ranging from 11.98' to 12.80' below the surface in the monitoring wells on site. These measurements indicate that the ground water gradient has trended from a northwest direction to a northeast direction, which coincides with the initial gradient measurements taken May 7, 1988 and is thought to be the true historic gradient direction. The ground water level is also dropping at approximately 0.01' per day as would be expected during the dry season and drought conditions. Chemical analysis of the water sampled from the monitor wells show that the ground water contamination is still localized at the northwest corner cf the site (MW-1) and has decreased to trace amounts of benzene and xylenes (0.6 and 4.1 ppb respectively). These levels do not exceed the DOHS Action Levels of 0.7 ppb for benzene and 100 ppb for xylenes. LIMITATIONS Western Geo-Engineers includes in this report the chemical analytical data from a state certified laboratory. The analytical results are performed in accordance to procedures suggested by the U.S. EPA and the State of California. Western Geo-Engineers is not responsible f.9r laboratory errors in procedures or results reported. The services performed by Western Geo-Engineers, Inc. have been conducted in a manner consistent with the level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions in the State of California and the Tracy area. Please note that contamination cti soil and/or ground water must be reported to the appropriate agencies in a timely _ :3 matter. No other warranty, expressed or implied, is made.