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<br /> A S S O C I A T E S I N C
<br /> monitoring wells and two of the soil borings were completed as vapor extraction wells The soil
<br /> boring, groundwater monitoring well, and vapor extraction well locations are shown on Figure 2
<br /> On July 3, 1997, the monitoring wells were developed and sampled for petroleum hydrocarbons
<br /> along with the adjacent property owner's well (CW) The samples from wells MW1, MW2, and
<br /> MW3 contained concentrations of total petroleum hydrocarbons as gasoline (TPHg) and benzene
<br /> ranging from 3,200 parts per billion (ppb) to 130,000 ppb and 920 to 11,000 ppb, respectively
<br /> Field activities and analytical results were detailed in Smith Technology's Summary Report dated
<br /> September 17, 1997
<br /> On March 24 and 25, 1998, ATC personnel supervised advancement of seven soil borings, ASB 1,
<br /> MW4, MW5, MW6, MW7, SB8, and SB9, at the site to depths ranging from approximately 26 5
<br /> to 62 feet bgs at the project site to 1) evaluate the horizontal and vertical extent of petroleum
<br /> hydrocarbon impacted soil and groundwater, 2) determine and define soil stratigraphy, and 3)
<br /> install groundwater monitoring wells (MW4, MW5, MW6, and MW7) within the uppermost
<br /> aquifer Groundwater samples collected from wells MW 5, MW6, and MW7 contained elevated
<br /> concentrations of TPHg and benzene Field activities and analytical results were detailed in
<br /> ATC's Summary Report of Subsurface Investigation!, dated August 14, 1998
<br /> SAMPLING ACTIVITIES
<br /> On June 26, 1998, groundwater samples were collected by ATC Associates personnel from
<br /> monitoring wells MW 1 through MW7 and CW The locations of the monitoring wells are shown
<br /> on Figure 2 Prior to collection of groundwater samples, the depth to water, pH, electrical
<br /> conductivity, and temperature were measured in the monitoring wells and recorded A minimum
<br /> of three well casing volumes were purged from each well prior to sampling The wells were
<br /> allowed to recover and samples were collected from each well using dedicated disposable bailers
<br /> The groundwater samples collected from each well were submitted to State-certified Sequoia
<br /> Analytical (FLAP Cert No 12 10) for chemical analysis of TPHg, benzene, toluene, ethylbenzene,
<br /> and xylenes (BTEX) utilizing EPA methods 8015/8020 In addition, the groundwater sample
<br /> from well MW5 was also analyzed for oxygenate fuel additives utilizing EPA method 8260, and
<br /> lead Groundwater well purge and sample logs are contained in Attachment 1
<br /> ANALYTICAL RESULTS
<br /> TPHg and BTEX were detected above laboratory method detection limits in the samples collected
<br /> from wells MW 1, MW2, MW3, MW5, MW6, and MW7 The samples collected from wells
<br /> MW4 and CW contained no detectable concentrations of petroleum hydrocarbons Oxygenate
<br /> fuel additives were not detected in the sample from well MW5, although the detection limits were
<br /> elevated due to dilution factors Lead was not detected in the groundwater sample from well
<br /> i MW5 A summary of analytical results is presented in Table 1 Laboratory data sheets and cham-
<br /> of-custody documentation are contained in Attachment 2
<br /> w 1977731*aA1yl2gr-1998 doc 2
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