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Er_ 4 May 1995 AGE-NC-95-0118 �. ; Page 2 of 4 of the former underground storage tank (UST), and advanced to a depth of 38 feet. TPH-g and BTE&X were detected at depths between 25 and 35 feet. During drilling, ground water was encountered at 36 feet. On 30 August 1994, three additional borings were drilled at the site to depths of 49 feet and completed as 2-inch ground water monitoring wells MW-1, MW-2 and MW-3. A total of 13 soil samples were analyzed for TPH as gasoline and BTE&X. Laboratory analyses detected TPH-g in 6 of the 13 samples analyzed. TPH as gasoline and BTE&X were detected in all four soil samples from B-1. The highest concentration of gasoline was detected in B-1 at a depth of 30 feet at 3,200 ppm. TPH-g and BTE&X were detected in two samples from MW-3; toluene was detected in one sample from MW-2; and xylenes were detected in three samples from MW-2. Noetroleum hydrocarbons were detected in samples from MW-1. p 2.4. GROUND WATER MONITORING 44 f The ground water monitoring wells were initially monitored and sampled in September 1994. The groundwater gradient was calculated to be 0.0029 ft/ft(0.17°) flowing southeast. ! Results of the groundwater samples indicated that TPH-g was detected in MW-1, MW-2 and MW-3 at concentrations of 280 pg/l(parts per billion: ppb), 9,500 ppb and 1,200 ppb, respectively. BTE&X were detected in samples from MW-2 and MW-3 at concentrations up to 1,600 ppb (toluene, MW-2). No BTE&X were detected in MW-1. The analytical results of all ground water samples are summarized in Table 2. 3.0. PROCEDURES 3.1. MONITORING WELL PURGE PROCEDURES On 10 May and 19 June 1995, the water level in each well was measured relative to the top of the casing using a Solinst water level meter(Table 1). After water levels were measured on 19 June 1995, approximately 6 gallons of water(a minimum of three well volumes) were evacuated from each well using a PVC bailer. Temperature, pH and conductivity were measured at one-gallon intervals using - an ICM model 52200 water analyzer. Stabilization data and field Iogs are included in Appendix A. The purged water was stored on-site in 55-gallon drums.