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,u U II Wright secured permission to enter the Gemelos Property and More for Less Station (also known as . Cheaper Gas Station) for casing elevation survey and to collect groundwater level measurements Wright had Triple"E" survey the additional well casings to a known sea-level referenced datum for groundwater level measurements for the three sites as required by and agreed with PHS-EHD for determmmg groundwater gradient(see attached Table 1) Groundwater Samplinu Monitoring well MW-1 was purged using calculated well volume based upon the depth to water in the casing. Depth to groundwater measurements were made to the nearest one-one hundredth of one foot,and the well was checked for the presence of separate phase product The well was purged to remove stagnant water in the well casing. As each purge volume was removed, measurements of pH, electrical conductivity and temperature were taken until these parameters stabilized over two purge volume removals, which is interpreted to represent aquifer water entering the casing. The well was allowed to recover to about 80% of the initially measured water level, miter which the sample was collected. Sampling was performed on September 21, 2000 i The water sample was carefully collected with a clean bailer and poured into the appropriate laboratory prepared container with minimum cavitation The water sample was labeled, logged onto a chain-of- custody form, and placed in a chilled ice chest Upon completion of well sampling, the well was sealed with an expansion plug and well box cover bolted down Subsurface Conditions The monitoring well was drilled immediately adjacent to Boring B-3 (within 0 5 foot) due the very close proximity of subsurface utilities, and the location of the previously observed dissolved contaminants The site stratigraphy showed a silty clay to a depth of about 6 feet This clay was underlain by sand and interbedded sand and clayey silt to depths of about 20 feet The interbedded sand and clayey silt strata compose the aquifer Water levels observed during drilling suggest that this is an unconfined to weakly confined aquifer A clayey sand forms the local confining stratum which underlies the uppermost aquifer zone sandy sequence This aquifer and confining soil stratigraphy is similar to that observed in the previous Wright borings(see Figures 1 and 2) Regional lithologic lateral and vertical variations are present in the shallow aquifer strata and underlying confining strata, which are typical for river and floodplain deposits in this portion of the San Joaquin Valley (see Geologic Cross Section, Figure 3) While lateral and vertical variation are present in the aquifer strata, these strata as a whole form the uppermost waterbearing aquifer (or hydro-) stratigraphy between about 10-to 20 feet in the area explored. These underlying coniimng strata display some lateral lithologic variation,and were not observed to yield water although the strata were very moist_ Chemical Analysis One (l) groundwater sample was analyzed at a State certified analytical laboratory from the exploratory boring These samples were chemically analyzed for the following, Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene (B), Toluene (7), Ethylbenzene (E) and Xylene (X), Methyl-tert-butyl-ether (MTBE) and fuel oxygenates, 1,2 Dtchloroethane and Ethylene Dibromide using EPA Methods 3510/8015,8020, 8240 and