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Cl <br /> 21 June 1996 <br /> i' AGE-NC Project No 95-0114 <br /> Page 2 of 4 <br /> 2.3. MONITORING WELL INSTALLATION AND SAMPLING <br /> Three ground water monitoring wells (MW-1, MW-2 and MW-3) were installed at the site in <br /> October 1993. Total petroleum hydrocarbons(TPH) and aromatic hydrocarbons (benzene, toluene, <br /> ethyl benzene and xylenes: BTE&X) were detected in soil samples collected from MW-3. Ground <br /> water samples were collected from each well on four occasions between November 1993 and <br /> December 1994. TPH as stoddard solvent (TPH-ss) and BTE&X were detected in water samples <br /> from each well. <br /> 2.4. CONTINUING SITE ASSESSMENT <br /> It is our understanding that a surge block lodged in the well during the development of MW-3. Since <br /> that time,MW-3 has consistently failed to produce sufficient ground water to meet the pre-sampling <br /> purge requirements requested by the PHS-EHD and CVRWQCB. Therefore, MW-3 was over drilled <br /> on 07 December 1995 and grouted to surface grade with Portland cement in accordance with well <br /> abandonment regulations established by the PHS-EHD. <br /> •' Three additional ground water monitoring wells were installed in December 1995: MW-3R, MW-4 <br /> and MW-5. Petroleum hydrocarbons were not detected in soil samples collected during the <br /> installation of these wells, however, hydrocarbon-impacted ground water was detected in samples <br /> collected from MW-3R. Results of installation procedures were included in the Quarterly Report- <br /> December 1995, prepared by AGE. <br /> 3.0. PROCEDURES <br /> 3.1. MONITORING WELL PURGE PROCEDURES <br /> On 19 March 1996, a Solinst water level meter was used to measure the depth to ground water in <br /> each well relative to the top of the well casing. The relative ground water elevation in each well and <br /> hydraulic gradient were determined from these data (Table 1). Free hydrocarbon product was not <br /> observed in any of the wells during the March 1996 sampling events. <br /> After ground water depths were measured, a pre-cleaned, two-stage submersible pump was used to <br /> purge wells MW-1, MW-2, MW-3R, MW-4 and MW-5. Approximately 8 to 10 gallons of water <br /> (minimum of three well volumes) were removed from each well to stabilize temperature, pH and <br /> conductivity. Well parameters were measured at 2-gallon intervals using an ICM water analyzer. <br /> . Purged water was stored in 55-gallon drums on-site. Monitoring well stabilization data and field <br /> data sheets are included in Appendix A. <br /> i <br />