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' n 20062 dQuarter Groundwater Report ' Frontier Transportation, Inc. August 2, 2006 Page 5 1 Monitoring well MW-3 was abandoned in May 2002 Replacement well MW-3R ' identified no detectable concentrations of dissolved TPH-d No other detectable concentrations of dissolved TPH-d were identified from laboratory analysis in any of the wells sampled since then, which includes the second quarter 2004 sampling episode Therefore, groundwater sample analysis for TPH-d has been discontinued at the site Historical gro} idwater monitoring results have identified TPH-g concentrations above ' 1,000 gg/L in MW-1, MW-3 and MW-3R Dissolved TPH-g concentrations in MW-1 had attenuated from 1,800 µg/L in August 1996 and remained under 50 µg/L from January 2000 to ' March 2005 (See Figure 6 for dissolved TPH-g over time in MW-I) Maximum dissolved TPH- g concentrations were 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 in April 2002 prior to abandonment detected dis lved TPH-g as 9,750 4g/L The maximum dissolved TPH-g concentration in MW-3R was��'pg/L in Qstober110�Since then, the dissolved TPH-g levels have decreased overtime to lower levels �aG 1 Groundwater collected in June 2006 from thirteen (13) monitoring wells identified six wells with dissolved TPH-g using EPA method 8015 modified Dissolved TPH-g was identified at a maximum of 3,150 µg/L in MW-8 The remaining five wells that identified dissolved TPH- I gas were MW-1, MW-3R, MW-4, MW-9 and MW-20 Monitoring well MW-4 had not identified dissolved TPH-gas since December 1998 'The June 2006 monitoring event was the first time that TPH-gas was identified in MW-8-,,No other wells identified TPH-g concentrations (<50 µg/L) See Table 1 See Figures 6 and 7 rn w In past sampling events no testable to trace concentrations (<5 8 µg/L) of dissolved BTEX were identified in monitors g wells MW-4, MW-5, MW-6, MW-7, MW-K, MW-9, MW- 10, MW-11, MW-12 and MW-14 19ince initial groundwater testing began in each well Monitoring wells MW-1 and MW-2 have remained at non-detect to trace levels since at least July of 1999 Monitoring well MW-13 contained 62 µg/L dissolved total BTEX in June 2002 but has remained non-detect since then Newly installed monitoring wells MW-15 throuh�M`W- 8 J�'yi5��¢ identified no detectable concentrations k�s�solved total BTEX during the 2004Y Ors an�second 8 quarter groundwater monitoring events my monitoring wells MW-3 and its replacementlacement MW- 3R contained dissolved BTEX from almost every groundwater sampling episode I