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Frontier Transportation, Inc. 425 Larch Road Site Assessment Work Plan May 6, 2005 ' Page 2 Groundwater samples were collected from MW- 1 , MW-2, and MW-3 on August 30, , I 1996 and April 21 , 1997 by Twinning. Results are presented in Table 1 . In January of 1998 , BEE advanced four (4) groundwater monitoring wells (MW-4 through MW4) 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. Results are tabulated in Table 1 . In January 2000, BEE advanced two borings (B-5 and B-6), installed four additional EI groundwater monitoring wells (MW-8 through MW41), and collected nine soil vapor samples for a soil vapor survey as part of an additional site assessment (See Figure 2). Soil sample _I 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 gg/kg as BTEX, and 10,600 µg/kg as MTBE at 10' bgs. Maximum soil vapor concentrations G were identified at sample point V5 at 4 ' bgs. Groundwater samples were subsequently collected l p Z) from all monitoring wells. Groundwater results are tabulated in Table 1 and soil vapor sample `` ff results are presented in Table 2. In May 2002, BEE 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, it 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 iii 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 I In June 2003 , BEE installed an additional groundwater monitoring well (MW- 14) screened from 30 ' bgs to 40 ' bgs. Soil sample results identified a maximum MTBE concentration of�l ,020 µg/kg at 10 ' bgs using EPA Method 8260B . No detectable TPH-g and BTEX were identified in MW- 14. hi 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' Nbgs. 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 C� f I