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allowed to recover and samples were collected from each well using dedicated disposable bailers
<br /> n 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 Laboratories,
<br /> Inc (Environmental Laboratory Accreditation Program Certificate No 2359) for chemical analyses of
<br /> TPI-Ig by EPA Method 801513, benzene, toluene, ethylbenzene, xylenes (BTEX) by EPA Method 802113,
<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, MW2, MW3, MW4, MW5, MW6, MW7, MW8, MW9, MW10, VW1,
<br /> VW2, and CW on March 23, 2006 The DTW measurements collected on March 23, 2006, were used to
<br /> determine the groundwater water gradient On March 23, 2006, water levels ranged from 23 25 to 26 67
<br /> feet below the tops of the well casing elevations, representing an average increase in the water table
<br /> ' elevation of approximately 1 59 feet since December 2005 The DTW data for MW1, VWI, and VW2
<br /> were not used for calculating the change in average groundwater elevation beneath the site since the VES
<br /> extracts groundwater from these wells while in operation The water level data were used to develop a
<br /> groundwater elevation contour map (Figure 3) Shallow groundwater beneath the site flowed toward the
<br /> northeast The average hydraulic gradient on March 23, 2006, was calculated to be approximately 0 008
<br /> ft/ft or approximately 42 ft/mile A summary of groundwater monitoring data is presented in Table 1
<br /> Groundwater Analytical Results
<br /> TPI-Ig and/or BTEX constituents were detected at or above laboratory reported detection limits in
<br /> groundwater samples collected from MW I, MW2, MW3, MW5, MW6, MW7,VW1, and VW2
<br /> ' The groundwater samples collected from MW4, MW6, and MW9 contained low concentrations of
<br /> MTBE ranging from 12 micrograms per liter(ug/1)to 3 0 ug/l The analyte 1,2-DCA was detected in the
<br /> groundwater sample collected from MW8 at a concentration of 1 0 ug/1 None of the groundwater
<br /> samples collected contained detectable concentrations of TBA, ETBE, TAME, DIPE, or EDB
<br /> According to the analytical lab, the samples were double checked by running through a second machine
<br /> and both runs yielded similar analytical results
<br /> ' A summary of analytical results is presented in Table 2 Groundwater laboratory data sheets and chain-
<br /> of-custody documentation are contained in Attachment 2
<br /> ' REMEDIATION SYSTEM
<br /> Remediation System Background
<br /> The installation and startup of the SVE/AS remediation system at the site is detailed in ATC's
<br /> Rernedration 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 /> 1 s lenvao1625961quart1yl1gr-2006 doc 3 ATC ASSOCIATES INC
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