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<br /> A S S O C I A T E S I N C
<br /> 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 was 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 /> After groundwater samples were collected, dissolved oxygen concentrations were measured in
<br /> each well Groundwater well purge and sample logs are contained in Attachment 1
<br /> The groundwater samples collected from each well were submitted to State-certified Argon
<br /> Laboratories, Inc (ELAP Cert No 2359) for chemical analysis of TPHg, benzene, toluene,
<br /> ethylbenzene, xylenes (BTEX) utilizing EPA methods 8015/8020, and methyl tertiary butyl ether
<br /> (MTBE), ethyl tertiary butyl ether (ETBE), tertiary butyl alcohol (TBA), tertiary amyl ether
<br /> (TAME), di-isopropyl ether (DIPE), 1,2-dichloroethane (1,2-DCA), and ethyl dibromide (EDB)
<br /> utilizing EPA method 8260
<br /> ANALYTICAL RESULTS
<br /> TPHg and/or BTEX were detected above laboratory method detection limits in the samples
<br /> collected from wells MWI, MW3, MW5, MW6, and MW7 The groundwater samples collected
<br /> from wells MW2, MW4, MW5, MW6, MW10, and CW contained low concentrations of MTBE
<br /> . ranging from 2 3 parts per billion (ppb) to 11 ppb The groundwater samples collected from
<br /> wells MWI, MW3, MW7, MWS, and MW9 did not contain detectable concentrations of MTBE,
<br /> but the detection limits in the sample in wells MWI, MW3, and MW7 were elevated due to
<br /> dilutions factors None of the groundwater samples collected contained detectable
<br /> concentrations of ETBE, TBA, TAME, DIPE, 1,2-DCA, or EDB The sample collected from
<br /> well CW contained no detectable concentrations of petroleum hydrocarbons other than a low
<br /> concentration of MTBE Groundwater samples from wells MWI, MW3, and MW7 continue to
<br /> contain the highest concentrations of TPHg and BTEX A summary of analytical results is
<br /> presented in Table 1 Laboratory data sheets and chain-of-custody documentation are contained
<br /> in Attachment 2
<br /> GROUNDWATER FLOW DIRECTION
<br /> Water level measurements were collected from wells MWI through MW10, and CW on June 12,
<br /> 2002 Water levels ranged from 22 39 to 25 95 feet below the tops of the well casing elevations,
<br /> representing an average decrease in the water table elevation of approximately 0 48 feet since
<br /> March 2002 The water level data were used to develop the groundwater elevation contour map
<br /> (Figure 3) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost
<br /> aquifer beneath the site flowed towards the northeast The average hydraulic gradient on June 12,
<br /> 2002 was calculated to be 0 007 ft/ft or approximately 35 ft/mile A summary of groundwater
<br /> monitoring data is presented in Table 1
<br /> w lwordpro1625961quart1yl2gr-2002 doc 3
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