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A A S S O C I A T E S I N C F monitoring wells and two of the soil borings were completed as vapor extraction wells The soil boring, groundwater monitoring well, and vapor extraction well locations are shown on Figure 2 On July 3, 1997, the monitoring wells were developed and sampled for petroleum hydrocarbons along with the adjacent property owner's well (CW) The samples from wells MW 1, MW2, and MW3 contained concentrations of total petroleum hydrocarbons as gasoline (TPHg) and benzene ranging from 3,200 parts per billion (ppb) to 130,000 ppb and 920 to 11,000 ppb, respectively Field activities and analytical results were detailed in Smith Technology's Summary Report dated September 17, 1997 On March 24 and 25, 1998, ATC personnel supervised advancement of seven soil borings, ASB 1, MW4, MW5, MW6, MW7, SB8, and SB9, at the site to depths ranging from approximately 26 5 to 62 feet bgs at the project site to 1) evaluate the horizontal and vertical extent of petroleum hydrocarbon impacted soil and groundwater, 2) determine and define soil stratigraphy, and 3) install groundwater monitoring wells (MW4, MW5, MW6, and MW7) within the uppermost aquifer Groundwater samples collected from wells MW5, MW6, and MW7 contained elevated concentrations of TPHg and benzene Field activities and analytical results were detailed in ATC's Summary Report of Subsurface Investigation, dated August 14, 1998 SAMPLING ACTIVITIES On September 24, 1998, groundwater samples were collected by ATC Associates personnel from monitoring wells MW1 through MW7 and CW The locations of the monitoring wells are shown on Figure 2 Prior to collection of groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in the monitoring wells and recorded A minimum of three well casing volumes were purged from each well prior to sampling The wells were allowed to recover and samples were collected from each well using dedicated disposable bailers The groundwater samples collected from each well were submitted to State-certified Sequoia Analytical (FLAP Cert No 1210) for chemical analysis of TPHg, benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA methods 8015/8020 Groundwater well purge and sample logs are contained in Attachment 1 ANALYTICAL RESULTS TPHg and BTEX were detected above laboratory method detection limits in the samples collected from wells MW1, MW2, MW3, MW5, and MW7, and TPHg was detected above laboratory detection limits in the sample collected from well MW6 The samples collected from wells MW4 and CW contained no detectable concentrations of petroleum hydrocarbons A summary of analytical results is presented in Table 1 Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 w 1977311givart1y\3qr-1998 doe 2