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i CALIFORNIA GEOPHYSICAL GROUP, INC. 6 P O Box 578341, Modesto, CA 95357 Te[ (209) 527-1247 May 3, 1995 Fox (209) 527-4810 Public Health Services , San Joaquin County P.O. Box 2009 Stockton, Ca 95307 a IcJJ RE: Quarterly Report May, 1995 Darpetro Service Station 7E7 fjV 749 E. Charter Way Stockton, Ca. Site # 1060 The site was sampled on April 25, 1995 and the laboratory analyses of the water samples were done by Sherwood Labs of Hilmar, California. The water table measurements, sampling parameters and chain of custody are attached. Table I lists the history of the water analyses taken at the site I since Jan. 26, 1990. Table II is the history of the water table measurements, and Table III list the history of hydraulic gradients. Attached is one water table elevation plot showing the approximate groundwater gradient. The water samples were obtained by using a pre--cleaned bailer. This was performed after the measured field parameters had stabilized during the purging. See protocols. Water samples were placed in appropriate glass containers with teflon-lined lids. iFINDINGS I The groundwater flow is to the North at a gradient of 0.0138 Ft/Ft. The groundwater level has risen about 4 .5 feet since the last reading. Figure 1 shows the water table elevations. This quarter groundwater was present in all of the wells. This is the first time this has happened since January 1990 . The rise in the water table has encountered soil which was contaminated ' and the contamination levels are high. Gasoline contamination is present in all of the wells above the California Action Levels. CONCLUSIONS The next quarterly monitoring will take place in July, 1995. Monitoring well water was removed from the site on March 6, 1995 IPage 1