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v a <br /> . A S S O C I A T E S I N C <br /> and groundwater are impacted by petroleum hydrocarbons Site activities were summarized in <br /> ATC's Summary Report of Subsurface Investigation, dated January 15, 1999 <br /> In December 2000, ATC personnel supervised the advancement of one cone penetrometer (CPT) <br /> boring to 140 feet bgs Also in December 2000 ATC personnel supervised the advancement of <br /> four soil borings to 80 feet bgs and one soil boring to 100 feet bgs The soil borings were <br /> converted into groundwater monitoring wells Analytical results of soil samples and <br /> groundwater samples indicated that soil and groundwater are impacted by petroleum <br /> hydrocarbons Site activities were summarized in ATC's Summary Report of 14dditional <br /> Subsurface Investigation, dated March 6, 2001 <br /> SAMPLING ACTIVITIES <br /> On June 19, 2001, ATC personnel collected groundwater samples from monitoring wells MW1, <br /> MW3 through MW8, and the on-site groundwater supply well DW A groundwater sample was <br /> not collected from well MW2 because of the presence of floating free product in the well The <br /> locations of the wells are shown on Figure 2 Prior to collection of groundwater samples, the <br /> depth to water, pH, electrical conductivity, and temperature were measured in the monitoring <br /> wells and recorded A minimum of three well casing volumes were purged from each <br /> monitoring well prior to sampling The wells were allowed to recover and samples were <br /> collected from each well using dedicated disposable bailers The surge tank from supply well <br /> DW was purged for five minutes prior to sampling <br /> The groundwater samples collected from each well were submitted to State-certified Argon <br /> Laboratories Inc (ELAP Cert No 2359) in Ceres, California for chemical analysis of total <br /> petroleum hydrocarbons as gasoline (TPHg) utilizing EPA method 8015 modified, benzene, <br /> toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA method 8020, and methyl tertiary <br /> butyl ether (MTBE), ethyl tertiary butyl ether (ETBE) di-isopropyl ether (DIPS), tertiary amyl <br /> ether (TAME), and tertiary butyl ether (TBA) utilizing EPA method 8260 Groundwater well <br /> purge and sample logs are contained in Attachment I <br /> ANALYTICAL RESULTS <br /> Groundwater samples collected from wells MW1, MW3, MW6, and MW8 contained elevated <br /> concentrations of TPHg and BTEX Concentrations of TPHg ranged from 11,000 parts per <br /> billion (ppb) in well MW8 to 160,000 ppb in well MW2 Concentrations of benzene ranged <br /> from 110 ppb in well MW8 to 4,300 ppb in well MW6 Groundwater samples collected from <br /> wells MW4 and MW7 contained detectable concentrations of TPHg and BTEX The <br /> groundwater sample collected from well MW5 contained no detectable concentrations of TPHg <br /> or BTEX Groundwater samples collected from wells MW1 through MW8 contained no <br /> detectable concentrations of oxygenate fuel additives although many of the reporting limits were <br /> elevated due to dilution The groundwater sample collected from on-site supply well DW <br /> contained detectable concentrations of BTEX, but contained no detectable concentrations of <br /> w 1163931quartlyl2gr-2001 doe 2 <br />