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Site Background Information <br /> ' Chapin Brothers Investments, Inc <br /> Page 8 of 12 <br /> cement A traffic-rated well box(8-inch diameter)was installed over each well,in accordance with <br /> County regulations <br /> Samples were collected at five-foot intervals, with samples were preserved by covering both ends <br /> of the brass sleeve with Teflon sheets, capping and sealing with tape TPH-g, BTE&X and <br /> oxygenated compounds were not detected in soil samples collected from the location of well MW-7 <br /> ' Soil samples collected from depths of 15, 20 and 25 feet bsg were analyzed <br /> ' REMEDIATION WELL INSTALLATION <br /> ' On 29 July 1997, three in-situ air-sparing (TAS) points (IAS-7 through IAS-9) were installed to <br /> depths of 25 and 15 feet bsg using AGE'S van-mounted Geoprobe 5400 soil probing machine Two <br /> probe borings were completed as IAS points using one 21-inch long, 318-inch I D stainless steel <br /> screen implant attached at 25 feet bsg to an anchor tip One additional probe boring was completed <br /> using one 21-inch long, 318-inch I D stainless steel screen implant set at a depth of 15 feet bsg <br /> Vinyl tubing (318-inch 0 D ) was extended from the sparging screen implant to the surface and a <br /> ' filter pack(fine glass beads) was installed around the screen implant from a depth of 20 to 25 feet <br /> bsg Bentonite sand(#8 bentonite)was used to make a 4-foot plug above the filter pack and the wells <br /> were grouted to surface grade with portland cement An eight-inch traffic box was installed at the <br /> surface for each TAS point <br /> ' SOIL VAPOR EXTRACTION - MASS OF RECOVERY <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 <br /> GROUND WATER REMEDIATION <br /> Based on an EHD office meeting conducted on 05 April 2000 the EHD and the Central Valley <br /> Regional Water Quality Control Board (CVRWQCB) verbally agreed on the use of ground water <br /> extraction and treatment to mitigate the site As note above an SVEIIAS system has been installed <br /> and operated at the site to remediate hydrocarbon-impacted soil and ground water Over the course <br /> of the remediation, rising ground water elevation has submerged a significant portion of <br /> contaminated soil below the ground water table and capillary fringe Under this condition, <br /> hydrocarbon-impacted ground water has remained and the overall influence of the IAS system has <br /> demonstrated diminishing effectiveness at reduction of dissolved hydrocarbons Areas in the eastern <br /> Advanced GeoEnvironmental,Inc <br />