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i 20033 rd Quarter Groundwater Report . Frontier Transportation November 14, 2003 Page 4 identified in March 1998 as 42,000 µg/L in MW-3, which was the shallowest recorded groundwater depth in that well Since then, dissolved TPH-g concentrations attenuated to a low of 100 µg/L The last groundwater sample collected from MW-3 prior to abandonment detected I dissolved TPH-g as 9,750 p.g/L Dissolved TPH-g concentrations in MW-1 have attenuated from 1,800 µg/L in August 1996 and remained under 50 µg/L since January 2000 14 Groundwater collected in October 2003 from ten groundwater monitoring wells identified dissolved TPH-g concentrations exclusively in MW-3R as 431 µg/L using EPA method 8015 modified The previous episode performed in June 2003 identified 668 µg/L as I TPH-g in MW-3R All other monitoring wells identified no detectable concentrations (c50 µg/L) of dissolved TPH-g from the third quarter 2003 sampling episode Please see Figure 4 for recent dissolved TPH-g isoconcentration map _. Historically no de ctabe�t, ntration f dissolved BTEX were identified in monitoringwells MW-5 MW-6 MWW-9 MW 10 and MW-11 since initial groundwater testing began in each well Monitoring wells -2, and MW-4 haver� „�],� remained non detect sii ce at least July of 1999 Only monitoring well MW-3, which was n rngralj 1,043 replaced by MW-3R, con ainecdissolved BTEX from every groundwater sampling episode �'�"�'v Detectable concentrations of dissolved BTEXw �e�ei�de tified exclusively in monitoring ' well MW-3R for the groundwater samples collected ince 03 Analytical results for MW-3R demonstrated a decrease in BTEX from 94 8 µg/L in June 2003 to 60 2 µg/L in October 2003 No detectable concentrations of dissolved BTEX were identified in the groundwater samples collected in October 2003 from the remaining thirteen monitoring wells using EPA method 8020 >7 , See Figure 5 for the recent dissolved BTEX Isoconcentration Map �d G MTBE was the only oxygenate identified in groundwater using EPA method 8260 from ' the third quarter 2003 sampling episode Monitoring well MW-1 identified dissolved MTBE concentrations at 8 4 µglL,a decrease from the maximum 5,800 µg/L identified in October 2002 ' Dissolved MTBE was also identified in June 2002 as 230 µg/L The depth to groundwater in —' x, 16 401 t' MW-1 was recorded as its lowest level (10 75') in June and October 2002, which coincides with the observance of increasing dissolved MTBE concentrations between those episodes 1J 1 ' Monitoring well MW-3 identified a maximum dissolved MTBE concentration of 29,400 µg/L in p D14� March 1998"Replacement well MW-3R identified a maximum dissolved MTBE concentration ' as 5,500 pg/L in January 2003 Third quarter 2003 groundwater analysis from MW-3R identified dissolved MTBE at 2,300 p,g/LAThe third quarter 2003 groundwater sampling identified dissolved MTBE at 23 µg/L from MW-14 No detectable concentrations of other oxygenates ' were identified from groundwater sample analysis of the monitoring wells sampled using EPA V-)-V11