Laserfiche WebLink
PUBLIC HEALTH SERVICES 'ppQu•�N <br /> SAN JOAQUIN COUNTY <br /> ENVIRONMENTAL HEALTH DIVISION " ° l�lli ` <br /> Karen Furst, M.D., M.P.H., Health Officer <br /> 304 East Weber Avenue, Third Floor - Stockton, CA 95202 ; <br /> 209/468-3420 '_`• +.l . ! <br /> CARL NAVARRA APR 15 1999 <br /> 485 SLEWETT RD <br /> TRACY CA 95375 <br /> RE: 7500 W. 111h Street SITE CODE: 1392 <br /> Tracy CA 95376 <br /> San Joaquin County Public Health Services, Environmental Health Division (PHSIEHD) <br /> has reviewed the communication titled "Corrective Action Plan — 7500 West 11th Street, <br /> Tracy, California" that was submitted by The San Joaquin Company Inc. on behalf of the <br /> above referenced site and has the following comments. <br /> On December 10, 1998 four underground storage tanks (UST) were removed under <br /> permit and inspection from the subject site. Four soil samples and one grab ground <br /> water sample were collected from the tank pit at a depth of approximately 9 feet below <br /> surface grade (bsg). Analytical results evidenced significant petroleum hydrocarbon <br /> contamination in both soil and groundwater. <br /> On December 21, 1998 the piping lines and former dispenser island area were <br /> excavated. Soil samples were collected from each area. While sampling the piping <br /> lines, four more very old underground storage tanks were discovered. These tanks were <br /> removed under inspection on December 28, 1998 and again, soil samples were <br /> collected. Following the discovery of the old tanks a search was made of the entire site <br /> for any more tanks or piping. Another piping line was excavated and soil samples were <br /> collected on January 5, 1999. Analytical results from each of the above discussed <br /> mobilizations evidenced petroleum hydrocarbon contamination, of varying levels, in the <br /> soil. Depth to ground water at the site was reported as being between 8 and 9 feet bsg. <br /> Vertical and lateral definition of petroleum hydrocarbon contamination in soil and ground <br /> water remains to be made at this site. The submitted "Corrective Action Plan" suggests <br /> the use of push-point technology to make this definition, but suggests that the <br /> investigation will only extend to 12 feet bsg_ As significant ground water and soil <br /> contamination was evidenced at 9 feet bsg, PHSIEHD considers it unlikely that that an <br /> investigation to 12 feet bsg will provide vertical definition of the contaminant plume. <br /> Please note that vertical definition is often considered to have been made after two <br /> consecutive five foot interval samples are reported as non-detect. Based on the <br /> analytical results obtained to date, it appears there may be more than one contaminant <br /> source area at this site. Once vertical definition of the contaminant plume has been <br /> made in the source areas, in both soil and ground water, lateral definition can be made. <br /> PHSIEHD agrees that the use of push point technology is an effective tool for site <br /> characterization, and recommends that some form of continuous core work be <br /> incorporated with its use. The site-specific lithological data that will be obtained from <br /> using either geoprobe continuous coring or CPT (cone penetrometer testing) will be <br /> A Division of San Joaquin County Health Care Services <br />