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i rk 24 October 1997 AGE-NC Project No 96-0235 Page 2 of 1 i performing a ground water monitoring event r S ' 4.0. PREVIOUS GROUND WATER MONITORING RESULTS The following discussion was compiled from reports prepared by Kleinfelder, Inc (KI), including ' Soil and Groundwater Assessment Report, dated 11 November 1994, ground water monitoring reports dated 03 January 1995, 18 May 1995, 14 December 1995, and 08 May 1996, and one undated data table Figure 3 = Ground Water Elevation - 04 April 1994 illustrates the ground water ' flow direction for the Kleinfelder monitoring event of 04 April 1994 Insufficient data was provided in other available reports to reconstruct ground water elevation maps for previous monitoring events ' Monitoring wells MW-1 and MW-2, screened between depths of approximately 40 to 60 feet bsg, are `drowned' wells since as late as April 1994 the surface of the ground water table has risen well above the tops of the screened intervals Monitoring well MW-3, with a screened interval of approximately 30 to 55 feet bsg, has had ground water above the screened interval since October 1995 The highest concentrations of TPH-g and volatile aromatics (benzene, toluene, ethylbenzene and xylenes BTE&X) in soil samples collected during well installations were encountered in MW-2 at a depth of 41 5 feet bsg, TPH-g was detected at 1,200 mg/kg and benzene was detected at 11 mg/kg , TPH-g concentrations encountered In ground water samples collected from the three wells during these monitoring events were as high as 35,000 parts per billion (ppb, reported as micrograms per ' liter), and may have been'higher as samples having gasoline-like odor were not analyzed Benzene concentrations were as high as 2,100 ppb, toluene as high as 4,200 ppb, ethylbenzene as high as 1,000 ppb, and xylenes as high as 3,500 ppb Despite being a `drowned' well, MW-2 appeared to ' be the most intensely impacted Table 1 presents the analytical data from these ground water monitoring events 1 5 0. STOCKPILED SOIL SAMPLING Excavated soil from the former UST over-excavation was stockpiled on site to aerate On 25 June 1996 and 08 November 1996, AGE sampled the stockpiled soil Sampling methods and analytical ' results are presented below - 51 PROCEDURES On 25 June 1996, an AGE representative collected eleven soil samples from various locations on the Advanced GeoEnvironmental,Inc'