Laserfiche WebLink
CS <br /> PUBLIC HIALTH S1u <br /> SAN JOAQUIN COUNTY Z <br /> ENVIRONMENTAL HEALTH DIVISION <br /> Karen Furst, M D , M PH , Health Officer - P <br /> 304 East Weber Avenue, Third Floor • Stockton, CA 95202 <br /> 2091468-3420 <br /> PAUL SUPPLE NOV 212000 <br /> ARCO PRODUCTS COMPANY <br /> P O BOX 6549 <br /> MORAGA CA 95470 <br /> RE ARCO Station #4932 SITE CODE 1136 <br /> 16 E Harding Way <br /> Stockton CA 95204 <br /> San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD) <br /> has reviewed the "Site Assessment Report" dated November 6, 2000 that was submitted <br /> by SECOR International Incorporated (SECOR) on behalf of the above referenced site <br /> and has the following comments <br /> The report details investigative site work that took place on August 21-22, 2000, when <br /> three groundwater monitoring wells, one soil vapor extraction (SVE) well, and one <br /> SVE/monitoring well were installed on site As described in the report, subsequent <br /> development and sampling of the wells took place on September 5, 2000 <br /> Results of the investigation indicate that both soil and groundwater have been <br /> significantly impacted by petroleum hydrocarbons and fuel oxygenate additives, and that <br /> the vertical and lateral extent of the impact has not been defined The highest <br /> concentrations of soil contamination appear in the area of the northern dispenser island, <br /> where analytical results from boring MW-4 had 4,190 mg/kg total petroleum <br /> hydrocarbons as gas (TPHg), 15 6 mg/kg benzene and 684 mg/kg methyl tertiary butyl <br /> ether (MtBE) Water samples were collected from all five wells on site Analytical <br /> results showed contaminant impacts to each well, at quantities up to 166,000 µg11 TPHg, <br /> 10,500 pg/l benzene, 43,600 µg/l toluene, 5,230 µg/l ethylbenzene, 25,400 pg/I xylene, <br /> 708,000 µg/I MtBE, 427 pg/I tertiary amyl methyl ether, 26,100 µg/I tertiary butyl alcohol <br /> and 23 8 pg/1 dichloroethane <br /> Routine quarterly groundwater monitoring must be initiated at this site, and must <br /> continue until directed otherwise from PHSIEHD PHS/EHD has not approved the use of <br /> a no-purge method of groundwater sampling at this site Both The California State <br /> Water Resources Control Board, as referenced in the Leaking Underground Fuel Tank <br /> (LUFT) Field Manual, and the United States Environmental Protection Agency (EPA) <br /> recommend that monitoring wells are purged until a minimum of three well volumes are <br /> removed, or until measured parameters of pH, temperature and conductivity of the <br /> discharged water stabilize to +/- 10% over two successive well volumes The next <br /> groundwater monitoring should be scheduled for early December 2000 <br /> A Division of San Joaquin County Health Care Services <br />