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02 April 2004 <br /> AGE-NC Project No 95-0143 <br /> Page 2 of 4 <br /> 2 2 1 Well Monitoring and Purging <br /> On 29 October 2003, a Solinst water level meter was used to measure the depth to ground water in <br /> twelve monitoring wells at the site and in fifteen monitoring wells at the neighboring Madison site <br /> relative to the tops of the well casings The ground water elevations(Table 1)and hydraulic gradient <br /> (Figure 3) were determined from these data <br /> After measurement of depths to water, between 4 and 13 gallons of water (approximately three <br /> casing-water volumes) were purged from wells MW-3, MW-6, MW-7, MW-10, MW-14 through <br /> MW-17, and MW-22 through MW-24 using a new disposable plastic bailer, and approximately <br /> 50 gallons of water were purged from well MW-9 using a Waterra inertial purge pump Temperature, <br /> pH and conductivity of the purged water were measured at regular intervals during purging using an <br /> Oakton water analyzer All purged water was stored on-site in 55-gallon DOT-approved drums Field <br /> data and field logs are included in Appendix A <br /> 2 2 2 Collection of Ground Water Samples <br /> • Water samples were collected from each purged well using a new, disposable bailer and, upon <br /> retrieval,were transferred into 40-m1 EPA-approved VOA vials containing 0 5 ml 18%hydrochloric <br /> acid as a sample preservative The samples were labeled and transported in a chilled container,under <br /> chain-of-custody protocol,to McCampbell Analytical,Inc (MAI),a California Department of Health <br /> Services (DHS)-certified laboratory The samples were analyzed for <br /> Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015 modified, and <br /> Benzene, toluene, ethylbenzene and total xylenes (BTEX) in accordance with EPA Method <br /> 8260B <br /> 3.0. FINDINGS <br /> Ground water elevation was calculated and flow direction was inferred from field data, the <br /> hydrocarbon impact to ground water was quantified from laboratory analysis <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> During the October 2003 monitoring event, the average depth to ground water at the site was <br /> 18 04 feet bsg Ground water was within the screened intervals of wells MW-10, MW-14 through <br /> Advanced GeoEnviron mental,Inc <br />