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i` <br /> 22 January 1996 <br /> AGE-NC Project No. 95-0112 <br /> Page 2 of 5 <br />' sampling was performed between 1987 and October 1992. By 1992, wells MW-2 and MW-3 went <br /> "dry" because the water level dropped below the screened intervals. <br /> Since October 1992, ground water has been sampled and analyzed on a quarterly basis. Petroleum <br /> hydrocarbon concentrations have fluctuated in most wells since 1992. Past and current analytical <br /> results of ground water samples are included in Table 3. <br /> 2.4. SOIL AND GROUND WATER REMEDIATION <br /> In anticipation of soil remediation at the site, boring RW-1 was installed in August 1993. Boring RW- <br /> P g <br /> 1 was drilled at a 15° angle from vertical from a surface location near the southeast corner of the <br /> building, and completed as a 4-inch diameter remediation well. A Final Remedial Plan(FRP) was then . <br /> prepared by Geological Audit Services, Inc. (GAS) in July 1994, outlining soil and ground water <br /> remediation procedures for the site. <br /> In May 1995, in-situ air sparging wells SW-1 and SW-2 were installed at the site. Subsequently, in <br /> M July 1995, a soil vapor extraction/in-situ air sparging (SVE/IAS) system was installed inside a fenced <br /> enclosure at the southeast corner of the Art & Artists building. The operation of the remediation <br /> system began in August 1995. <br /> 3.0. PROCEDURES <br />' 3.1. MONITORING WELL PURGE PROCEDURES <br />' On 20 October 1995, a Solinst water level meter was used to measure the depth to ground water in <br /> each well except MW-2 relative to the top of each casing. The relative ground water elevations were <br /> calculated by subtracting the ground water depth from the surveyed casing elevation (Table 1). Using <br />' the ratio of changes in ground water elevation to distance, the hydraulic gradient was calculated. <br /> After depth to ground water measurements, monitoring wells MW-1 and MW-3 to MW-8 were <br /> purged using pre-cleaned PVC bailers. At least three well volume of water were removed from wells <br /> MW-4 through MW-8. However, due to poor recharge, three well volumes could not be removed <br /> from MW-1 nor MW-3. <br /> Ground water stabilization parameters were measured at regular intervals in each well using an ICM <br /> water analyzer. Purged water was stored on-site in 55-gallon drums. Stabilization data and field logs <br /> are included in Appendix A. <br /> 1 <br />