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I <br /> PUBLIC HEALTH SERVICES <br /> G <br /> SAN JOAQUIN COUNTY s� <br /> N i <br /> JOGI KHANNA M D M P H <br /> Healrh Officer <br /> cq �P <br /> P 0 Box 2009• (1601 East Hazelton Avenue) • Stockton, Cahforrua 95201 �'F O A <br /> (209) 468-3400 <br /> MR RICK SISK Cc f l9 <br /> UNOCAL CORPORATION <br /> 2000 CROW CANYON PLACE, SUITE 400 NO 0 61992 <br /> SAN RAMON, CA 94583 <br /> RE: 601 E. KETTLEMAN LANE SITE CODE: 1348 <br /> i <br /> Public Health Services Environmental Health Division (PHS/EHD) has <br /> reviewed your request for partial (soil) site closure of the above <br /> referenced site, dated October 7, 1992 . While the information <br /> outlined in your request is informative and accurate, PHS/EHD has <br /> the following concerns: <br /> 1) Although the levels of contaminates are very low, they are <br /> . still above detection limits, and very deep. As an example, <br /> the results of soil samples from monitoring well number one <br /> (MW-1) were not below detection limits until a depth of 47 . 5 <br /> feet below ground surface (bgs) was reached. The highest <br /> groundwater measurements, taken from San Joaquin County Flood <br /> Control maps of 1983 and 1986, indicate water has been as <br /> shallow as approximately 50 feet, thus contaminated sail is <br /> within 5 feet of highest groundwater. <br /> 2) Monitoring well six (MW-6) is approximately 50 horizontal feet <br /> from where the sample from the eastern fuel tank (TPH-G <br /> 3 , 900ppm and Benzene 7. 4ppm) was collected and soil <br /> contamination was found at 60 and 74 feet bgs at the time of <br /> its installation. <br /> 3) Monitoring well two (MW-2) is up-gradient from the suspected <br /> point of release, yet it has shown contamination every <br /> quarter. PHS/EHD recognizes that these levels appear to be on <br /> the decline, but previous water results still place question <br /> on the source. <br /> Additional soil investigation, to determine the extent of soil <br /> contamination around the tank pit should be conducted. Current and <br /> new data should be utilized to draft a Remedial Action Plan that <br /> would address the low levels which persist in the soil and <br /> groundwater, particularly between the tank pit and monitoring wells <br /> . 2 and 6 . <br /> A Dmsion of tan Joaquw County Health Care Sermnces .r <br />