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1F 1 <br /> Mr Michael Infiarna <br /> Page 2 <br /> Prior to sampling, monitoring wells MW 1 through MW5 were purged of a minimum of three well <br /> casing volumes During the purging process, temperature, pH and electrical conductivity <br /> parameters were measured <br /> Samples were collected after parameter stabilization, and appropriate water level recovery Purge <br /> water was contained in properly labeled DOT-approved 55-gallon drums The drums are currently <br /> being stored onsite Purge logs are included in Attachment A <br /> Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (ELAP <br /> 42359) Analysis consisted of TPHg and TPHd using modified EPA method 8015B, gasoline <br /> oxygenate additives, ethylenedibromide (EDB) and 1,2-dichloroethane (1,2-DCA) using EPA <br /> method 8260B, and BTEX using EPA method 8021B <br /> As requested by the San Joaquin Environmental Health Department and the Regional Water Quality <br /> Control Board additional analyses were done on all samples collected The samples were <br /> additionally analyzed for CAM 17 metals using EPA Method 200 Series, Cr6 by EPA Method 218 6, <br /> anions (Cl, NO3, SO4) by EPA Method 300 0, cations (Ca, Mg,Na, K) by EPA Method 7000 Series, <br /> DO by SM 4500, and TDS and TSS by EPA Method 160 1 and 160 2 <br /> Groundwater Analytical Results <br /> • EDB and 1,2-DCA were not detected in any site well BTEX, TPHg, TPHd and gasoline <br /> oxygenates were not detected in wells MW 1, MW2, MW4 and MW5 <br /> i <br /> In well MW3, TPHg was detected at a concentration of 2,300 parts per billion (ppb) Toluene, <br /> ethylbenzene, and xylenes were detected at concentrations of 0 7 ppb, 1 0 ppb and 1 9 ppb, <br /> respectively TPHd was detected at a concentration of 6,000 ppb Methyl-tert-butyl ether (MTBE) <br /> was detected at a concentration of 900 ppb Analytical results are summarized in Table 2 <br /> Attachment B contains laboratory reports and chain of custody documentation Graphs of TPHg, <br /> TPHd and MTBE concentrations over time in MW3 are included in Attachment C <br /> The results of the additional analyses done on all samples can be found in the laboratory report <br /> included in Attachment B <br /> Summary <br /> Groundwater levels at the site fell since the previous round of sampling The average <br /> groundwater gradient across the site was 0 004-0 005 ft/ft Groundwater flowed <br /> predominantly in a northerly direction <br /> • EDB and 1,2-DCA were not present above laboratory method detection limits (MDLs) in any <br /> site well Gasoline oxygenates, TPHg, BTEX, and TPHd concentrations were less than MDLs <br /> • in wells MW1, MW2, MW4 and MW5 <br /> G IGROUNDMWOO]SEY CHnQMR12OO414QM2004 doc <br />