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13 <br /> PPI <br /> Chemical Analytical Methods and Results <br /> Nine groundwater samples were analyzed using EPA Methods 5030/8015, 802 and 8260 f or <br /> Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene, Toluene, Ethylbenzene and Xylene <br /> (BTEX) and fuel oxygenates including Methyl-tert-butyl-ether (MTBE), Tert-Butyl Alcohol <br /> (TBA), Dl-Isopropyl Ether (DIPE), Ethyl tert-butyl ether (ETBE), Tert-Amyl Methyl Ether <br /> TAME), 1,2-Dichloroethane (1,2-DCA) and Ethylene Dlbromide (EDB) The analytical results <br /> of the groundwater samples for this sampling event are attached and listed below in Table <br /> 1(historic data is presented in Table 2), <br /> Table 1 Current Quarter Groundwater Chemical Data <br /> Sample TPHG Ben Tol Ethyl Xyl MTBE TBA DIPE ETBE TAME <br /> u /I u /I u /l u /l u /l u /I u /I u /I u /l u /I <br /> MW-1 ND NO NO NO NO NO NO NO ND NO <br /> MW-2 3400 33 79 230 120 NO NO NO NO NO <br /> MW-3 680 43 14 42 82 NO NO NO NO NO <br /> MW-4 NO NO NO NO NO NO NO NO NO NO <br /> MW-5 NO NO NO NO NO NO NO NO NO NO <br /> MW-6 530 ND 44 NO NO NO NO NO NO NO <br /> MW-7 NO NO NO ND NO NO NO NO NO NO <br /> MW-8 NO NO NO NO NO NO NO NO NO NO <br /> MW-9 13000 1300 100 710 1400 NO NO NO NO NO <br /> Blank NO NO NO NO NO NO NO NO NO NO <br /> NO - None detected ug/I - micrograms per liter Ben - Benzene Tol Toluene Xyl - Xylene <br /> Fuel Ox - Fuel Oxygenates by Method B260 from Dec , 1997 forward Ethyl - Ethylbenzene <br /> 1,2 Dichloroethane and Ethylene Dibromide NO in all wells <br /> Discussion <br /> Groundwater flow direction is north-northeasterly at a low flow gradient which is consistent <br /> with historically observed trends Contaminants were observed in the Wells MW-2, MW-3, <br /> MW-6 and MW-9 Contaminants were not observed in MW-1, MWA MW-5, MW-7 or MW- <br /> 8 <br /> W- <br /> 8 Contaminant concentrations generally declined in Wells MW-3 and MW-6, but rose in well <br /> MW-2 Contaminants declined in MW-9 with the exception of Benzene Groundwater mounds <br /> have formed on-site in the past Current water level data indicates that leakage form the <br /> irrigation line and canal could affect the site <br /> Concentrations continue to vary which indicates that desorbtion influences the concentration <br /> levels observed depending upon fluctuating aquifer water levels--and-the-contaminant-absorbtion <br /> to soil (see discussions in previous reports) These concentration variation trends are <br /> attributed to a fluctuations in water levels and contaminant desorbtion from the aquifer <br /> sediment/soil in the immediate vicinity of the wells, and fluctuations are expected to continue <br />