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19 July 2000 AGE-NC Project No 96-0232 Page 26 of 29 bsg), MW-11D (screened 130 to 150 feet bsg), MW-12A (screened 10 to 20 feet bsg) and MW-13B (screened 50 to 60 feet bsg) at concentrations as high as 10 µg/l • The greatest encountered concentration of dissolved TPH-d is off-site in MW-12 (screened 10 to 20 feet bsg) and MW-13 (screened 10 to 20 feet bsg and 50 to 60 feet bsg) Lesser concentrations of dissolved TPH-d were encountered in MWA I (screened 65 to 75 feet bsg) and MW-9A (screened 40 to 50 feet bsg) • Minor concentrations of TAME, ETBE and TBA were detected in the area of MW-1 • The elevated petroleum hydrocarbon concentrations detected in water samples collected from well MW-1 (screened between 9 and 24 feet bsg) suggest this well may be screened within or near the dissolved petroleum hydrocarbon "core area" of the plume • The increase in quantified MTBE concentrations detected from well MW-1 during the April, May and June 2000 monitoring events may be related to the extraction of ground water from the adjacent extraction well EW-1 (screened 8 to 33 5 feet bsg) • Between the April and the June 2000 monitoring events, MTBE concentrations have decreased from 20 Fcg/1 to 9 9 ,ug/l in samples collected from the Rocky's domestic drinking water well (RDW-1) • Methanol was detected in ground water samples collected from Flag City municipal water • well No 1 and No 2 (CSA-1, CSA-2) at concentrations of 120µg/1 and 73 4g11, respectively as part of the 28 April 2000 monthly monitoring event • AGE suspects the high concentrations of ethanol detected in ground water samples collected from the multi-level monitonng wells were due to the coated bentonite pellets utilized during construction of the wells Samples of the '/4-inch coated bentonite pellets (Sinclair Services) were submitted In a VOA container filled with bottled water for laboratory analysis for ethanol The laboratory analysis detected dissolved ethanol at a concentration of 22,000µg11 Thereafter, AGE requested MSDS sheets from Sinclair Services, as well as other industry bentonite pellet manufacturers from Colloid Environmental Technologies Co (CETCO) and Polymer Drilling Systems (Pel-Plug) The MSDS sheets from all three bentonite pellet manufacturers listed ethyl alcohol and ethyl acetate on the bentonite coating The low concentrations of ethanol detected in previous samples may be valid data, but the high concentrations detected in samples from the multi-level wells appear to be due to introduction of the bentonite pellets 12.0. CONCLUSIONS Soil characteristics data previously collected from CPT bonngs P13 through P17 was utilized to construct llthologlc cross sections from which AGE defined five tentative hydrologic units The Adtanced CeoEmlrounlenlal,Inc