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• 2004 3 Quarter Groundwater Report ' Frontier Transportation January 10,2005 Page 2 In January of 1998, Blakely Environmental Investigations, Inc (BEH) advanced four(4) groundwater monitoring wells (MW-4 through MW-7)to assess the extent of subsurface contamination beneath the site (See Figure 2, Site Layout Map). Soil samples were collected ' every five feet. Laboratory analysis of soil samples identified no detectable concentrations of TPH-g,BTEX, or MTBE Groundwater samples were subsequently collected and results are ttabulated in Table 1. In January 2000, BER advanced two borings (B-5 and B-6), installed four additional ' groundwater monitoring wells (MW-8 through MW-11), and collected nine soil vapor samples for a soil vapor survey as part of an additional site assessment (See Figure 2, Site Layout Map for well locations) Soil sample analysis identified no detectable concentrations of petroleum ' hydrocarbons with the exception of boring B-6 Maximum contammant levels in B-6 were identified 100 mg/kg as TPH-g, 2,343 pg/kg as BTEX, and 10,600 µg/kg as MTBE at 10' bgs Maximum soil vapor concentrations were identified at sample point V5 at 4' bgs Groundwater ' samples were subsequently collected from all monitoring wells Groundwater results are tabulated in Table 1 In May 2002,BEII installed two additional groundwater monitoring wells (MW-12 and MW-13) screened from 30' bgs to 40' bgs Soil sample results identified maximum TPH-g, BTEX, and MTBE concentrations of 700 mg/kg, 115,000 µg/kg, and 25,000 µg/kg in soil collected from MW-13 at 10' bgs Soil concentrations attenuate by 99% at 15' bgs No detectable TPH-g, BTEX, and MTBE were identified in MW-12 Also, monitoring well MW-3 was abandoned prior to excavation and removal of 325 tons of impacted soil and replaced by ' MW-3R In June 2003, BEH installed an additional groundwater monitoring well (MW-14) screened from 30; bgs to 40' bgs_ Soil sample results identified a maximum MTBE concentration oil 420 µg/kkg at 1.O�gs using EPA Method 8260B No detectable TPH-g and BTEX were identified in MW-1 v Wt In January 2004, BEI[ installed four additional groundwater monitoring wells Deep ' monitoring wells MW-15, MW-16 and MW-18 were advanced to 40' bgs and screened from 30' bgs to 40' bgs Shallow monitoring well MW-17 was advanced to 20' bgs and screened from 5' bgs to 20' bgs Soil sample results identified a maximum MTBE concentration of 1,310 µg/kg at 10' bgs m MW-15 using EPA Method 8260B No other oxygenates or lead scavengers were detected The maximum TPH-gas detected was 1.7 mg/kg at 10' bgs in MW-15 using EPA Method 8015M No detectable BTEX was identified in the soil column for MW-15 through MW-18 See Figure 2 for well locations. •