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' 2005 1"Quarter Groundwater Report . Frontier Transportation April 28, 2005 ' Page 4 \1 �z�'�S ether(ETBE), tertiary amyl methyl ether (TAME), - ' d sing EPA method 8260 Laboratory analysis results for all monitoring episodes are presented in Table 1 Recent laboratory analytical reports are included as Appendix B ' Historical groundwater data has identified dissolved TPH-m in monitoring well MW-3 exclusively Maximum concentrations of dissolved TPH-m were identified in MW-3 as 33,000 ' µg/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 BEII concludes 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 1 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 have attenuated to non-detect in April, August, and November of 2001 Groundwater analysis results 1 from April 2002 identified dissolved TPH-d exclusively from MW-3 as 14,200 µg/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 were limited in MW-1 only once at 1,800 µg/L, in MW-3 and in MW-3R Dissolved TPH-g concentrations in MW-1 have attenuated from 1,800 µg/L in August 1996 and remained ' under 50 pg/L since January 2000 (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 pg/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 pg/L The last groundwater sample collected from MW-3 in April 2002 prior to abandonment detected dissolved TPH-g as 9,750 pg/L The maximum dissolved TPH-g concentration in MW-3R was 3,790 µg/L in October 2002 Since /JO 'yob)b S then, the dissolved TPH-g levels have decreased over time t - roundwater L collected in March 2005 from nine (9) groundwater monitoring wells identified only one well U with dissolved TPH-g at 342 µg/L in MW-3R using EPA method 8015 modified See Figure 7