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I 2004 1" Quarter Groundwater Report • Frontier Transportation I May 20, 2004 Page 4 exclusively Maximum concentrations of dissolved TPH-m were identified in MW-3 as 33,000 gg/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 BE][[, therefore, has discontinued groundwater sample analysis for TPH-m at the site No,yno-+rr otI was -i-ndacd q ,w 44t YYV �Pla� Laboratory analysis identified dissolved TPH-d in monitoring well MW-3 at a maximum concentration of 33,000 gg/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 ' from April 2002 identified dissolved TPH-d exclusively from MW-3 as 14,200 gg/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 i entified from 1 oratory analysis in any of the wells sampled since then, which includes the t q arter 200 sampling episode Groundwater analysis for TPH-d will continue �r ' • to be performed for the site ° Historical groundwater monitoring results have identified TPH-g concentrations above ' 1,000 gg/L were limited in MW-1 only once at 1,800 gg/L, in MW-3 and in MW-3R Dissolved TPH-g concentrations in MW-1 have attenuated from 1,800 gg/L in August 1996 and remained under 50 gg/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 gg/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- in April 2002 prior to abandonment detected dissolved TPH-g as 9,750 gg/L The maximum Sissolved TPH-g concentration in MW-3R was 3,790 gg/L in October 2002 Since ' then, the dissolved TPH-g levels have steadily decreased over time (See Figure 7) Groundwater collected in March 2004 from all eighteen (18) groundwater monitoring ' wells identified no detectable concentrations of dissolved TPH-g concentrations (<50 gg/L) using EPA method 8015 modified The previous episode performed in December 2003 identified 984 ' gg/L as TPH-g exclusively in MW-3R Historically no detectable to trace concentrations (<5 8 µg/L) of dissolved BTEX were 1 identified in monitoring wells MW-4, MW-5, MW-6, MW-7, MW-8, MW-9, MW-10, MW-11, 1 i 1