Laserfiche WebLink
Wm. I Hunter & Associates 2220 Loma vista Dr. <br /> Registered Geologists Sacramento, CA 95825 <br /> Petroleum &Mineral Appraisers (916) 972-7941 <br /> i FAX (916) 972-1683 <br /> June 22, 1998 <br /> Jeffry Wong, REHS <br /> San Joaquin County PHS <br /> Environmental Health Division <br /> Site Mitigation Unit <br /> P.O. Box 388 <br /> Stockton, CA 95201-0388 <br /> RE: First Quarter 1998 Groundwater Monitoring Report - 913 W. Fremont St., <br /> Stockton, CA. Site Code 1114 <br /> We have enclosed a copy of the field report, laboratory analyses, a groundwater gradient <br /> map, and maps showing inferred lines of equal concentration of benzene, toluene, ethyl- <br /> benzene, xylene, and TPHg. The field work was performed by Del-Tech Geotechnical <br /> Support Services on April 1, 1998 as directed by the County EHD. <br /> The attached PLATE I shows the potentiometric surface based upon this latest sampling <br /> event, along with the 12 measurements taken since monitoring began. The gradient <br /> continues to be to the north/northwest at about ,006'/ft. <br /> Groundwater was measured at an average depth of 6.54' msl datum- a rise of 2.44' since the <br /> last event. <br /> TABLE I summarizes the results of the laboratory analyses of water samples from MW-1 <br /> since monitoring began. Except for the suspect samples collected in December, 1995, all <br /> components have been below detection levels. <br /> TABLE H shows the results of water samples from MW-2, which is located down <br /> gradient from the removed UST. BTEX& TPHg have been measured at varying <br /> concentrations since first sampled. Although the levels of BTEX& TPHg have gone down <br /> significantly since the December, 1997 event, this is most likely due to the 2'+ rise in the <br /> water table, and the fact that the top of the screen is at 15'bgi. <br /> TABLE M summarizes lab results from MW-3. Minor amounts of BTEX & TPHg were <br /> recorded from the March, 1997 sampling, and benzene, ethylbenzene, & xylene were <br /> detected in June, 1997. All compounds were below detection levels from the December, <br /> 1997 and April, 1998 sampling. <br /> TABLE N shows the results of water samples from MW4. There was no soil or ground <br /> water contamination measured during the work, and the four sampling events since <br /> 1 <br />