Laserfiche WebLink
a <br /> Chemical Analysis and Results <br /> The samples were transported to Chromalab, Inc in Pleasanton, CA The groundwater samples <br /> were analyzed using EPA Methods 5030/ 8015 and 602 for Total Petroleum Hydrocarbons as <br /> Gasoline (TPHG), Benzene, Toluene, Ethylbenzene and Xylene (BTEX) and fuel oxygenates <br /> including Methyl-tert-butyl-ether (MTBE) by EPA Method 8260 The analytical reports are <br /> attached, and the results are listed below in Table 2 (see Table 3 for historic data) <br /> Table 2. Groundwater Chemical Data <br /> Well No Date TPHG` Benzene Toluene Ethylbenz Xylene Fuel Ox <br /> ------------------------------- u g/I ----------------------------- <br /> MW-1 3131/98 9,000 1 ,400 130 880 500 ND <br /> MW-2 3/31/98 ND ND ND ND ND ND <br /> MW-3 3/31/98 ND ND ND ND ND ND <br /> MW-4 3/31/98 130 ND ND ND ND ND <br /> Blank 3131198 ND ND ND ND ND ND <br /> ND - None detected NA - Not Analyzed ug/l - micrograms {ger liter <br /> Fuel Ox - Fuel oxygenates by Method 8260 <br /> Discussion <br /> Groundwater flow direction appears consistent with historically observed trends The <br /> concentrations in Well MW-1 reflect an increase of levels of BTEX, and are attributed to <br /> residual contaminants being flushed into the groundwater from the soil strata in the immediate <br /> vicinity of the former tank pit MTBE was not detected in any well TPHG was observed at <br /> MW-4 for the first time This occurrence is interpreted is attributed to rising groundwater <br /> levels and desorbtion of TPHG residuals near MW-1 <br /> Tetrachloroethene and 1,2-Dichlorethene (CIS) were not observed in any well Thc3c <br /> contaminants were observed only once at very low concentrations dust above detection limits <br /> It is possible that the previous observation could have been laboratory error as this <br /> contaminants have not been reported at this site <br /> Monitoring Schedule <br /> The quarterly monitoring for this site is scheduled to continue at quarterly intervals It is our <br /> understanding that the San Joaquin Valley RWQCB has requested that all fuel oxygenate <br /> compounds be chemically analyzed by EPA Method 8260 in the future for fuel release sites, and <br /> Wright will continue the addition of those compounds to the program for the next sampling <br /> Page 3 <br />