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CVATC
<br /> • A S S O C I A T E S I N C
<br /> In June and July 2000, WHF supervised the advancement of ten soil borings at the site and
<br /> completed five of the borings as groundwater monitoring wells MWS, MW6, MW8, MW9, and
<br /> MW10, and three of the borings as vapor extraction wells VE1, VE2, and VE3 Groundwater
<br /> monitoring well MW7 was replaced by vapor extraction well VE3 Soil samples collected from
<br /> borings B101, B103, B104, VE3, and VE 1 contained detectable concentrations of TPI-Ig and
<br /> BTEX
<br /> SAMPLING ACTIVITIES
<br /> On May 19, 2003, wells MW 1 through MW6, MW8, and MW9 were redeveloped due to the
<br /> time lapse since the last monitoring event Well MW 10 was found to be damaged and an
<br /> obstruction was noted in the well at a depth of approximately 10 feet and well development was
<br /> not able to be performed The wells were purged until the extracted water was relatively
<br /> sediment free Development logs are included in Attachment 1 Purge water was temporarily
<br /> stored on site in DOT approved 55-gallon drums Groundwater samples were collected by ATC
<br /> Associates personnel from onsite domestic well and an offsite (Phillips) domestic well were
<br /> sampled
<br /> On May 23, 2003, groundwater samples were collected by ATC personnel from monitoring wells
<br /> MW1, MW2, MW3, MW4, MWS, MW6, MW8, and MW9 The locations of the monitoring
<br /> wells are shown on Figure 2 Prior to collection of groundwater samples, the depth to water, pH,
<br /> electrical conductivity, and temperature were measured in the monitoring wells and recorded A
<br /> minimum of three well casing volumes was purged from each well prior to sampling The wells
<br /> were allowed to recover and samples were collected from each well using dedicated disposable
<br /> bailers After groundwater samples were collected, dissolved oxygen was measured in each well
<br /> The groundwater samples collected from each well were submitted to Argon Laboratories Inc
<br /> (ELAP Cert No 2359), a California-certified analytical laboratory, for chemical analysis of
<br /> TPHg and total petroleum hydrocarbons as diesel (TPHd) utilizing EPA method 8015, BTEX
<br /> utilizing EPA method 8020, and MTBE, tertiary butyl alcohol (TBA), di-isopropyl ether (DIPE),
<br /> ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), 1,2-dichloroethane (1,2-
<br /> DCA), and 1,2 dibromoethane (EDB) utilizing EPA method 8260 Groundwater well purge and
<br /> sample logs are contained in Attachment 1
<br /> GROUNDWATER FLOW DIRECTION
<br /> Water level measurements were collected from wells MW1, MW2, MW3, MW4, MW5, MW6,
<br /> MW8, and MW9 on May 19, 2003 and on May 23, 2003 On May 19, 2003 water levels ranged
<br /> from 69 92 to 75 09 feet below the tops of the well casing elevations The water level data were
<br /> used to develop the groundwater elevation contour map (Figure 3) Assuming horizontal
<br /> isotropic conditions, groundwater flow in the uppermost aquifer beneath the site on May 19,
<br /> . 2003 varied across the site, but in general, the flow was southeasterly The average hydraulic
<br /> gradient was calculated to be 0 03 ft/ft or approximately 135 ft/mile On May 23, 2003 water
<br /> S\Enviromenta11252911reportsl2QR-2003 doc 2
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