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' from each well using dedicated disposable bailers Groundwater well purge and sample logs are
<br /> contained in Attachment 1
<br /> The groundwater samples collected from each well were submitted to State-certified Argon Laboratories,
<br /> Inc (Environmental Laboratory Accreditation Program Certificate No 2359) for chemical analyses of
<br /> TPHg by EPA Method 8015B, benzene,toluene, ethylbenzene, xylenes (BTEX) by EPA Method 8021B,
<br /> ' and methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary butyl alcohol (TBA),
<br /> tertiary amyl ether (TAME), di-isopropyl ether (DIPE), 1,2-dichloroethane (1,2-DCA), and ethyl
<br /> dibromide(EDB)by EPA Method 8260B
<br /> Groundwater Flow Direction
<br /> DTW was measured in MW1 through MW10, VWl, VW2, and CW on May 12, 2005 Water levels
<br /> ranged from 24 27 to 28 69 feet below the tops of the well casing elevations, representing an average
<br /> increase in the water table elevation of approximately 0 81 feet since March 2005 The DTW data for
<br /> VW1 and VW2 were not used for calculating the change in average groundwater elevation beneath the
<br /> site since the calculated groundwater elevations increased in MW1 through MW10 and CW and
<br /> decreased in VW 1 and VW2 The water level data were used to develop a groundwater elevation
<br /> contour map (Figure 3) Shallow groundwater beneath the site flowed toward the northeast The average
<br /> ' hydraulic gradient on May 12, 2005, was calculated to be approximately 0 008 ft/ft or approximately 42
<br /> ft/mile A summary of groundwater monitoring data is presented in Table 1
<br /> Groundwater Analytical Results
<br /> TPHg and/or BTEX constituents were detected at or above laboratory reported detection limits in
<br /> groundwater samples collected from MW 1, MW2, MW3, MW5, MW6,MW7, VW 1, and VW2
<br /> The groundwater samples collected from MW3, MW4, MW5, MW6, MW7, MW9, and CW contained
<br /> low concentrations of MTBE ranging from 0 8 micrograms per liter (ug/1) to 4 3 ug/l The analyte 1,2-
<br /> DCA was detected in the groundwater sample collected from MWS at a concentration of 12 ug/l None
<br /> of the groundwater samples collected contained detectable concentrations of TBA, ETBE, TAME, DIPE,
<br /> or EDB According to the analytical lab, the samples were double checked by running through a second
<br /> ' machine and both runs yielded similar analytical results
<br /> ' A summary of analytical results is presented in Table 2 Groundwater laboratory data sheets and cham-
<br /> of-custody documentation are contained in Attachment 2
<br /> REMEDIATION SYSTEM
<br /> Remedration System Background
<br /> ' The installation and startup of the SVE/AS remediation system at the site is detailed in ATC's
<br /> Remediation System Installation Report for the Farmer Property, 610 North Hunter Street, Stockton,
<br /> California, dated April 8, 2003 Figure 4 shows the layout of the remediation system equipment compound,
<br /> ' associated piping, and remediation well network at the site Table 3 provides the well completion detail A
<br /> more detailed description of each of the system components follows
<br /> s\envrro1625961quartlyl2gr-2005 doc 3 ATC ASSOCIATES INC
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