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1 i i � Project No. E6576.001 �� ►tional Groundwater Sampling/W. Clover 22 March 1995 I r determined downgradient direction from B-2, appeared to penetrate only shallow fill, with 4.� native soils below 2 feet. A grab sample of water was taken from B-3. MW-4 was then located five feet in the downgradient direction from B-3. L MW-4 was drilled the same day (October 17, 1994) to a depth of 25 feet, with soil samples taken every 5 feet below 10 feet. Groundwater was first encountered at 14 feet during the drilling, which was done with an auger drill rig utilizing 8-inch diameter hollow-stem flight g g augers. Details regarding the geology and as-built installation are given in Figures 6 and 12, Appendix A. No evidence of hydrocarbon contamination was observed during the drilling and installation of MW-4. The location of MW-4 was then surveyed by a licensed civil engineer C, with well collar elevation determined to 0.01 feet. The four soil samples were transported in a chilled cooler to a State-certified laboratory for testing. The ends of the 2"x4" cylindrical brass retainers were covered with aluminum foil, capped with polyethylene lids, and taped with �+ duct tape. Well Development: MW-4 was developed on 10/19/94 by bailing with a re-usable teflon bailer. Recharge capacity was high, with minimal water level drop. Approximately 10 casing volumes (30 gallons) were removed. Turbidity, which was moderate, appeared to decrease. slightly after ' about 25 gallons were bailed. Purge water was a light reddish brown color, similar to that obtained from MW-2, but in contrast with light-grey purge water from MWA and MW-3. L r Sampling: L On 10/21/94, MW-1, 2, and 3, were re-sampled in the company of Steve Sasson (PHS- r EHD) and MW-4 was sampled following purging and after pH, conductivity, and temperature had stabilized. At least three well volumes were removed during purging. Details of the sampling event are given in Appendix B. For each well, samples were collected in one 1-liter amber jar and two 40-m1 glass volatile organic analysis ("VOA") vials with Teflon septums as specified by the RWQCFB and EPA. All sample containers were new. The samples were accompanied from the field to the laboratory by a chain-of-custody and analysis request form, copies of which are given in Appendix C. Prior to sampling, water levels were measured. Page 4 TERRASEARCH, INC.