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February 14 1997 f Page 10 t . Well MW-l 1 is screened from 43 to 73 bgs Review of the quarterly monitoi ing data indicate a marked trend of attenuation to non detectable concentrations of petroleum hydrocarbons prior to the well becoming submerged It is true that 67 ppb TPPH-g was reported in July 27 1995 (with no detectable benzene) when the well was submerged (by less than six inches) The October 1995 sampling of Well MW-1 1 with approximately , three inches of submerged screen again reported no detectable concentrations of petrbleuin hydrocarbons The well is currently submerged by over 5 feet however the trend of attenuating concei'itrations of petroleum hydrocarbons to near or below detectable concentrations was established prior to the well becoming significantly submerged Well MW-8 was located adjacent to Well MW-1 1, had a much shorter screen length (24 to 39 feet), and was screened across the groundwater surface Well MW-8 located less than 25 feet from Well MW-11 and closer to the source area reports no detectable concentrations of petroleum hydrocarbons in groundwater and, as concurred by the SJCEHD is representative of downgradient groundwater quality conditions Groundwater sampling results are deemed representative of site conditions with the exception of Wells MW-9 and MW-13 Groundwater Monitoring Wells MW-10, MW-1 1, MW-14, and MW-2R all reported cion-detectable concentrations of petroleum hydrocarbons in groundwater prior to the well screens becoming submerged Therefore, those data are viewed as being representative Wells MW-9 and MW-13 reported detectable Concentrations of petroleum hydrocarbons prior to, and after becoming , submerged Well MW-4 is located proximal to submerged Well MW-9, and Wells MW-5 and MW-6 are located between the source area and submerged Well MW-13 During the April and July and October 1996 sampling events, rising ` groundwater was sampled in Wells MW-4 through MW-6, and is therefore representa- tive of site conditions The SJCEHD disagree that the g7oundwater sampling residts [with the exception of Wells MW-9 and MW-13] are repiesentat7ve of site conditions Also, the wells which wei e installed in 1989 which are pi operly screened for current water levels have been _ destroyed to accommodate the development of the site One well, A4W-8 was destroyed despite PHS1EH1)a protest that it was not within the proposed development's footprint and it provided the downgiadient well which Gould monitor 7 cpresentanve groundwater quality Due to the rising groundwater conditions and prior to being abandoned, Well MW-8 was sampled during three consecutive events during 1996 No concentrations of petroleum hydrocarbons were detected The SJCEHD concurred that Well MW-8 prior to being abandoned provided representative downgradient groundwater quality data Additionally, as discussed previously, Well MW-11 also defines the extent of petroleum 320I337B\CLOSLFRE3