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2005 4`' Quarter Groundwater Report .7 Frontier Transportation, Inc. 5 ' February 13, 2006 .(h Page 5 ' seven wells with dissolved TPH-g using E h 8015 modified Dissolved TPH-g was identified at a maximum of 88,900 µg/L MW-21, his is the highest level of dissolved TPH-g ever identified in the groundwater As in previous groundwater monitoring events, MW-1, MW- 2, MW111k, MW-9, MW-17 and MW-20 identified dissolved TPH-gas None of the deep wells � 5461 (MW43`through MW-16 and MW-18) identified TPH-g MW-19 was the only shallow well 4 y%� sampled that did not have detectable dissolved TPH-g(<50 µg/L) See Table 1 See Figures 6 � and 7 cow c,e r, +'•d1�S 6 a F ($7 r r/f i-�G�C3� 1 r n In past sampling events no detect a to trace concentrations(<5 8 µg/L) of dissolved BTEX were identified in monitoring w s MW4, MW-5, MW-6, MW-7, MW-8, MW--9, MW- 10, MW-11, MW-12 and MW-14 si a initial groundwater testing began in each well Momtonng wells MW-1 an -2 ve 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 through MW-18 identified no detectable concentrations of dissolved total BTEX during the 2004 first and second ' quarter groundwater monitoring events Only monitoring wells MW-3 and its replacement MW- 3R contained dissolved BTEX from almost every groundwater sampling episode abbYnW';2_1 Detectable coi66trations of dissolved BTEX were identified in monitoring wells MW-2,— MW-3R W-2,MW-3R and MW-19 for the groundwater samples collected in December 2005 See Figure 8 for dissolved benzene in MW-1 and Figure 9 for MW-3R "Analytical results from MW-3R demonstrated a significant increase in total dissolved BTEX from 221 6 µg/L in December 2003 to 1,319 5 µg/L in December 2005 -Dissolved benzene was detected above the MCL in MW-2 and MW-3R at 3 4 µg/L and 640 µg/L, respectively No detectable concentrations of dissolved BTEX were identified in the groundwater samples collectedom the re among ten (10) 100 )AA- monitoring wells See Figure 10 for the recent dissolved BTEX Isoconcentration Map MTBE was identified above MCL in rune groundwater wells (MW-1, MW-2, MW-31k, tae• , MW-9, and MW-17 through MW-21) using EPA method 8260 from the fourth quarter 2005 r sampling episode The current California Department of Health Services (CDHS) primary t �a Maximum Contaminant Level (MCL) for MTBE in groundwater is 13 µg/L Monitoring well �4 ,} MW-1 identified dissolved MTBE concentrations at 2,270 µg/L in December 2005, which is aGv'� decrease from the maximum concentration of 8,100 µg/L in September 2004 '(See Figure 11 forEr�' ' MTBE m MW-1 overtime) Monitoringwell MW-3 identified a maximum dissolved MTBE •y= � concentration of 29,400 µg/L in March 1998 "This well was abandoned in May 2002 ' Groundwater analysis for replacement well MW-3R identified a maximum dissolved MTBE concentration of 6,000 µg/L in Decem er 2003 Dissolved MTBE in MW-3R for December 2005 ' ' was identified at 2,310 µg/L, anid�rc ase from the previous sampling event (See Figure a>7 j�,�r �,1�,04 �l 1 1