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' . 2005 2rid Quarter Groundwater Report ' Frontier Transportation, Inc. August 5, 2005 Page 4 ' Historical groundwater data has identified dissolved TPH-m in monitoring well MW-3 exclusively Maximum concentrations of dissolved TPH-m were identified 1n MW-3 as 33,000 ' �tg/L in January 2000 using EPA method 8015 modified In January 2000, the well cover for MW-3 was destroyed allowing oily surface water to infiltrate the well Blakely Environmental ' Investigations, Inc concluded that the damaged well cover caused the increase in TPH-m in MW-3 from November 1999 to May 2000 Dissolved TPH-m concentrations have remained non- detect at the site since September 2000,when the well cover was repaired Therefore, ' groundwater sample analysis for TPH-m has been discontinued at the site Laboratory analysis identified dissolved TPH-d in monitoring well MW-3 at a maximum ' concentration of 33,000 µg/L in January 2000 However,the groundwater results were reported as TPH-d and TPH-m combined Since then, dissolved TPH-d concentrations in MW-3 attenuated to non-detect in April, August, and November of 2001 Groundwater analysis results ' from April 2002 identified dissolved TPH-d exclusively from MW-3 as 14,200 pg/L The groundwater level in MW-3 dropped to its lowest recorded depth(10 72') in April 2002 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 groundwater monitoring results have identified TPH-g concentrations above 1,000 µg/L in MW-1, MW-3 and MW-3R Dis-solved 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-1) 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 Thedast groundwater sample collected from MW-3 in April 2002 prior to abandonment detected dissolved TPH-g as 9,750 µg/L The maximum dissolved TPH-g concentration in MW-3R was 3,790 µg/L in,October 2002 Since then, the dissolved ' TPH-g levels have decreased over time to lower levels _ ' Groundwater collected ;n June 2005 from nine (9) monitoring wells identified four wells with dissolved TPH-g using EPA method 8015 modified Dissolved TPH-g was identified at 700 µg/L, 450 gg/L, 500 µg/L and 120 pg/L in monitoring wells MW-1, MW-3R, MW-9 and MW- ' 17, respectively The June 2005 monitoring event identified dissolved TPH-g in MW-1 for the -�4rlt time since November 1999, and for the first time ever in wells MW-9 and MW-17 (first sampled • in January 2000 and March 2004, respectively) MW-3R typically has detectable concentrations 1