Laserfiche WebLink
Wm. I Hunter & Associates 2220 Loma Vista Dr <br /> Registered Geologists _ Sacramento, CA 95825 <br /> Petroleum &Mineral Appraisers (916) 972-7941 <br /> 20 FAX {916) 972-1683 <br /> August 17, 1998 <br /> " Margaret Largorio, Supervising REHS <br /> Site Mitigation Unit <br /> San Joaquin County PHS <br /> Environmental Health Division <br /> 304 East Weber Ave , Third Floor <br /> Stockton, CA 95202 <br /> RE: SECOND QUARTER 1998 GROUNDWATER MONITORING REPORT FOR <br /> 2969 LOOMIS ROAD, STOCKTON, CA. SITE CODE 2015 <br /> This report covers the results of the work done on July 1, 1998 by DelTech Geo- <br /> Technical Support Services as directed by our office and witnessed by a representative of <br /> the San Joaquin County EHS The report includes a map showing the potentiometric <br /> surface based upon the latest work, gradient directions since work began, a summary of all <br /> water analyses since initiation of the project, DelTech field notes, custody chains, and <br /> copses of the laboratory analyses The depth to water was measured in all four wells, but <br /> as instructed by the San Joaquin Co EHD, only MW-1 & MW-4 were sampled <br /> aThe approximate potentiometric surface is shown on PLATE I. The hydraulic gradient is <br /> to the northeast, and is very flat, about 0006'/ft (3 17' per mile ) The water table has <br /> risen an average of 2 67' since the last sampling in March, 1998, the highest level since <br /> monitoring began A review of PLATE H shows that the gradient has been highly <br /> divergent at this location, with no predominant direction of flow This supports our <br /> previous conclusions that there is little or no horizontal communication between this site <br /> and other aquifers in the area <br /> TABLE A summarizes the results of all water analyses since initiation of the project <br /> BTEX& TPHg were below detection levels in MW-1, TEPH as diesel measured 0.318 <br /> mg/L, in March it was 0.435 TEPH as diesel in MW-4 decreased from 11.5 mg/L in <br /> March to 2.27 mg/L BTEX & TPHg were not detected in MW-4,however,the <br /> detection hmits had be raised due the high concentration of TEPH Refer to the <br /> laboratory sheets attached for more information <br /> CONCLUSION: <br /> The data continues to show a very limited aquifer at this location The contamination is <br /> restricted to a very small area beneath the removed tanks, and there is no evidence of <br /> extensive lateral movement The amount of gasoline components measured at this site <br /> have been extremely low to non-detect Although TEPH as diesel is present at detectable <br /> . levels, there are no apparent lateral conduits to allow it to migrate any distance from the <br /> source -the removed UST's <br /> 1 <br />