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' 20052• rid Quarter Groundwater Report ' Frontier Transportation, Inc. August 5, 2045 Page 2 ' In January of 1998, Blakely Environmental Investigations, Inc (BEII) 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 tabulated in Table 1 ' In January 2000 BEE 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 contaminant levels in B-6 were identified 100 mg/kg as TPH-g, 2,343 µg/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, BEII installed an additional groundwater monitoring well (MW-14) screened from,30 bgs to 40' bgs Soil sample results identified a maximum MTBE concentration of1,020'µg/kg at 10'-bgs using EPA Method 8260B No detectable TPH-g and BTEX were identified in MW-14�o is' In January 2004, BEE 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 in 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=l5 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 1