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Figure 7 represents TPHg and Benzene measurements obtained in March 1997 <br /> Figure 8 represents TPHg and Benzene measurements obtained in March 1998 <br /> Table i represents groundwater chemical results showing TPHg MBTEX and DO <br /> Charts have been developed for MWI, MW2, MW3, MWS, MW10 and MW12 that show the <br /> continued decline in concentrations of TPHg in the groundwater and the continued rise of the <br /> groundwater elevation since 1991 These charts are located with Table I A computer generated <br /> averaging trend line demonstrates the decline of gasoline range hydrocarbons in the groundwater for <br /> all wells except for MW12, which is currently showing a slight upward trend <br /> For the most part the MCLS for Benzene, Toluene, Ethylbenzene and Xylenes have not exceeded the <br /> primary MCLs for drinking water standards for the State of Calf ronia And the perimeter wells, <br /> except MW12, have tested below or at laboratory lower detection Iimits for TPHg, BTEX and <br /> MTBE, showing plume stability <br /> Of the wells that do test positive for gasoline range hydrocarbons (MWI, MW2, MW3, MW8, <br /> MW10, MW12 and MW13) the following MCLs have not been exceeded with the exception of the <br /> December 1997 sampling wluch contain elevated levels for BTEX due to residuals in the pump <br /> Compound Primary MCL Secondary MCL <br /> Benzene 10 ug/L none <br /> Toluene 150 ug/L 42 ug/L <br /> Ethylbenzene 700 ug/L 29 ug/L <br /> Xylenes 1750 ug/L 17 ug/L <br /> MWI, which contained free product until August 1992 nas not exceeded the primary and secondary <br /> MCLS since December 1993 <br /> MW2 is situated in a clayey facies of the silty sand aquifer beneath this site and has low <br /> transmtssivrty has not exceeded the primary MCLs for Ethylbenzene since December 1996 <br /> MW3 which contained free product until November 1992 has not exceeded the primary MCLs for <br /> Toluene, Ethylbenzene and Xylenes since March 1993 and the secondary MCLs for Toluene since <br /> September 1993 and for Ethylbenzene since September 1995 <br /> MW8, which is downgradient and offsite, did not exceeded the primary MCLs for Toluene during <br /> this latest sampling It has never exceeded the primary MCLs for Ethylbenzene and has been below <br /> the primary MCLs for Xylenes since June 1994 <br /> 3 R603 Update#51 5/98 <br />