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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 8021 B,
<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 MWIO, VWI, VW2, and CW on March 1, 2005 Water levels
<br /> ranged from 24 75 to 29 05 feet below the tops of the well casing elevations, representing an average
<br /> Increase In the water table elevation of approximately 1 29 feet since December 2004 The water level
<br /> data were used to develop a groundwater elevation contour map (Figure 3) Shallow groundwater
<br /> beneath the site flowed toward the northeast The average hydraulic gradient on March 1, 2005, was
<br /> calculated to be approximately 0 011 ft/ft or approximately 58 ft/mile A summary of groundwater
<br /> 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 MWl,MW2,MW3, MWS, MW6, MW7, VW I, and VW2
<br /> The groundwater samples collected from MW2, MW4, MW5, MW6, MW7, MW9, MW10, and CW
<br /> contained low concentrations of MTBE ranging from 1 0 micrograms per liter (ug/l) to 7 1 ug/l TBA
<br /> was detected n the groundwater samples collected from MW2 and MW7 at concentrations of 37 ug/l and
<br /> • 12 ug/l, respectively 1,2-DCA was detected in the groundwater sample collected from MW8 at a
<br /> concentration of 13 ug/1 None of the groundwater samples collected contained detectable
<br /> concentrations of ETBE, TAME, DIPE, or EDB According to the analytical lab, the samples were
<br /> double checked by running through a second machine 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 remediation system at the site is detailed In ATC's Remediation
<br /> System Installation Report for the Farmer Property, 610 North Hunter Street, Stockton, California, dated
<br /> April 8, 2003 Figure 4 shows the layout of the remediation system equipment compound, associated piping,
<br /> and remediation well net work at the site Table 3 provides the well completion detail A more detailed
<br /> description of each of the system components follows
<br /> Vapor System
<br /> The new vapor extraction equipment (i e , 300 cubic feet per minute (cfm) thermal oxidizer) was
<br /> installed at the site on April 7, 2005 but was not operated during the first quarter 2005 The 500-gallon
<br /> propane above ground storage tank(AST) for supplemental fuel supply, necessary hoses, pipes, gauges to
<br /> transfer the propane, subsurface piping and wellhead connections between the SVE remediation wells,
<br /> the AS remediation wells and the fenced remediation equipment compound were still present
<br /> s lenviro1625961quart1y\Igr-2005 doe 3 ATC ASSOCIATES INC
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