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CALIFORNIA GEOPHYSICAL GROUP, INC. <br /> P O Box 578341, Modesto, CA 95357 Tel (209) 527-1247 <br /> January 31 , 1995 Fox (209) 527-4810 <br /> Public Health Services <br /> San Joaquin County <br /> P.O. Box 2009 r � <br /> Stockton, Ca 95307 ~ <br /> z <br /> RE: Quarterly Report January, 1995 h, <br /> Darpetro Service Station <br /> 749 E. Charter Way <br /> Stockton, Ca. <br /> Site # 1060 icy <br /> The site was sampled on January 25 , 1995 and the laboratory <br /> analyses of the water samples were done by Sherwood Labs of <br /> Hilmar, California. The water table measurements, sampling <br /> parameters and chain of custody are attached. <br /> Table I lists the history of the water analyses taken at the site <br /> since Jan. 26 , 1990 . Table II is the history of the water table <br /> measurements, and Table III list the history of hydraulic <br /> gradients. Attached is one water table elevation plot showing <br /> the approximate groundwater gradient. <br /> The water samples were obtained by using a pre-cleaned bailer. <br /> This was performed after the measured field parameters had <br />' stabilized during the purging with a pump. See protocols. Water <br /> samples were placed in appropriate glass containers with teflon- <br /> lined lids. <br />' During sampling, several of the well locking caps appeared to be <br /> not functioning properly. These caps have been replaced with new <br /> locking caps. <br /> FINDINGS <br />' The groundwater flow is to the East Northeast at a gradient of <br /> 0.0012 Ft/Ft. The groundwater level has risen about 0. 34 feet <br /> since the last reading. Figure 1 shows the water table <br />' elevations . <br /> Gasoline contamination is present in all of the wells above the <br /> California Action Levels. Well BM-9 had TPH contamination of <br />' 36100 ug/kg, which is more than twice the amount of contamination <br /> found in well BM-7. Well BM-7 is located closer and up gradient <br /> to the contamination source on this site, therefore, the <br /> contamination found in BM-9 is suspected to have originated off <br /> site. <br />' Page 1 <br />