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<br /> diameter PVC casing, with MW8, MW9, MW10, and MW11 extending to a depth of 65 feet bgs in
<br /> the shallow groundwater bearing zone, MWS, MW6, and MW 12 extending to a depth of 90 feet bgs
<br /> in the intermediate groundwater bearing zone, and MW7 extending to a depth of 121 feet bgs in the
<br /> deep groundwater bearing zone.
<br /> Monitoring wells MW5, MW6, MWS, MW9, MW 10, and MW12 were developed on December 22
<br /> and 23, 2004. An obstruction encountered in MW7 at approximately 64 to 65 feet bgs prevented
<br /> development of this well. MWl 1 was purged dry after removing 0.5 gallons of water. Efforts to
<br /> ' develop this well using a bailer revealed the presence of grout inside the well and the total depth of
<br /> the well was measured to be approximately 58 feet.
<br /> ' On December 22 and 23, 2004 monitoring wells MW I through MW12 were surveyed relative to
<br /> NAD 83 and NGVD29 for position and elevation and groundwater samples were collected from
<br /> MW1 through MW6, MW8, MW9, MW10, and MW12. Petroleum hydrocarbon constituents were
<br /> ' detected in soil samples collected from the boreholes of MW5 through MW9 and MW12.
<br /> Groundwater samples were not collected from MW7 and MW1 I due to an obstruction in MW7 and
<br /> grout infiltration in MW 1 I. Petroleum hydrocarbons were detected in the groundwater samples
<br /> ' collected from MW 1 through MW6, MW8 through MW 10, and MW 12. The results of the subsurface
<br /> investigation activities are presented in ATC's Subsurface Investigation Report, dated July 25, 2005.
<br /> FIRST QUARTER 2005 SAMPLING ACTIVITIES
<br /> The depth to water was measured in MWI through MWI2 (Figure 3) on March 30, 2005. Monitoring
<br /> wells MW3, MW4, MW5, MW9, MW10, and MW12 were purged on March 30, 2005, and the
<br /> remaining wells were purged on March 31, 2005. On March 31, 2005, groundwater samples were
<br /> collected from MW1 through MW10 and MW12. MW11 was not sampled due to grout infiltration
<br /> ' which occurred during well installation activities in November 2004. Prior to collection of
<br /> groundwater samples, the depth to water was measured in the wells and the pH, electrical
<br /> conductivity, and temperature were measured in groundwater purged from the monitoring wells and
<br /> ' recorded. A minimum of three well casing volumes were purged from each monitoring well prior to
<br /> sampling. Approximately 9.7 well casing volumes were removed from MW7 to develop this well, as
<br /> MW7 was not previously developed. The wells were allowed to recover and samples were collected
<br /> from each well using disposable polyethylene bailers.
<br /> The groundwater samples collected from each well were submitted to State-certified Argon
<br /> ' Laboratories (Environmental Laboratory Accreditation Program Certification. No. 2359) in Ceres,
<br /> California for chemical analyses of total petroleum hydrocarbons quantified as gasoline (TPHg)
<br /> utilizing EPA Method 8015M; and benzene, toluene, ethylbenzene, and xylenes (BTEX), methyl
<br /> ' tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE) di-isopropyl ether (DIPE), tertiary
<br /> amyl ether (TAME), tertiary butyl ether (TBA), 1,2-dichloroethane (1,2-DCA), and 1,2-
<br /> dibromoethane (EDB) utilizing EPA Method 8260B. Groundwater well purge and sample logs are
<br /> included in Attachment 1.
<br /> s:lenviromenta11283491reports12005 1 &2 QMR.doc 2 ATC Associates Inc.
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