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Site Background Information Chapin Brothers Investements, Inc <br /> Page 11 of 12 <br /> Grab ground water samples were collected from the influent of each well and the effluent of the <br />' treatment system Samples were collected in laboratory-supplied 40-m1 EPA-approved volatile <br /> organic analysis (VOA) vials containing 0 5 ml 18% hydrochloric acid as a preservative Effluent <br /> samples were collected in the (VOA) vials, 1-liter amber bottles without preservative and 500- <br /> milliliter plastic bottles without preservative The samples were analyzed for TPH-g,BTEX,MTBE, <br /> Volatile and Semi-volatile compounds (VOC and SVOC), Metals Cd, Cr, Cu, Pb, Ni and Zn in <br /> accordance with EPA Method 200 Modified and pH <br /> Dissolved hydrocarbon concentrations detected from ground water samples collected at the influent <br /> end of the treatment system generally declined over the quarter The concentration of benzene <br />' detected in the influent treatment samples was reduced by an average of 70%,during the remediation <br /> period <br /> GROUND WATER TREATMENT <br /> Between 15 April and 19 September 2003, the ground water extraction and treatment system <br /> processed approximately 302,703 gallons of water The total volume of ground water treated as of <br /> 30 September 2003 is approximately 2,459,705 gallons, an estimated that approximately 5,700 <br /> gallons of water was discharged per day during this time Cumulative totals of 5 69 lbs of benzene <br /> and 140 lbs of TPH-g are estimated to have been extracted since ground water treatment began on <br /> ' 02 April 2002 <br /> ' GENERAL OVERVIEW <br /> A soil vapor extraction (SVE) lin-situ air-spargmg (IAS) system was installed and operated at the <br /> ' site from April 1996 to late June 1999 to remediate hydrocarbon-impacted soil and ground water <br /> However,over the course of the SVE remedial action,rising ground water elevation had submerged <br /> a significant portion of contaminated soil,leaving a greatlyreduced vadose zone addressable by SVE <br /> ' technology and apparently rendering IAS ineffective due to a thicker saturated zone and diminished <br /> ability to recover sparged air Areas in the eastern portion of the site and at the northwest corner of <br /> the site had not demonstrated a sustained reduction of dissolved hydrocarbons Subsequently a more <br /> effective remedial system was required <br /> In accordance with EHD/CVRWQCB directives and approval,AGE conducted three separate ground <br /> water extraction pumping tests in March 2001 Analysis of the groundwater extraction data indicted <br /> that ex-situ ground water treatment was feasible,the radius of influence generated by a pumping rate <br /> of three gallons per minute is interpreted to be adequate to control further off-site migration of <br /> contaminants toward the west <br /> ' Advanced GeoEnvironmental,tnc <br />