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2006 2"a Quarter Groundwater Reportort Frontier Transportation, Inc. August 2, 2006 z� y, Page 4 4.0) QUARTERLY GROUNDWATER SAMPLE RESULTS ' BEA contracted Del-Tech to collect groundwater samples from 13 of the monitoring wells at the site on June 23, 2006 for laboratory analysis Monitoring wells sampled were MW- 1, MW-3R, MW-4, MW-8, MW-9, and MW-13 through MW-20 Groundwater parameters (pH, temperature, and conductivity) were measured before, during, and after well purging (See Appendix for Monitoring Well Field Logs) Monitoring well MW-21 identified a thin layer of product on the surface of the water and monitoring well MW-2 identified slight sheen droplets on the surface of the water Groundwater taken from these wells in March 2006 was sampled and analyzed and found to have elevated dissolved MTBE and TPH-gas Dissolved MTBE was identified at 8,000 µg/L in MW-21 and 5,190 µg/L in MW-2, and dissolved TPH-gas was identified at 231,000 µg/L in MW-21 and at 6,100 µg/L in MW-2 Groundwater samples were analyzed for TPH-g using EPA methods 8015 and for BTEX, MTBE, tertiary butyl alcohol (TBA), di-isopropyl ether (RIPE), ethyl tertiary butyl ether(ETBE) and tertiary amyl methyl ether (TAME) using EPA method 8260 Laboratory analysis results for all monitoring episodes are presented in Table 1 Recent laboratory analytical reports are included as Appendix N I Historical groundwater data has identified dissolved TPH-m in monitoring well MW-3 exclusively Maximum concentrations of dissolved TPH-m were identified in MW-3 as 33,000 µg/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 Blakely Environmental Investigations, Inc concluded 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 Therefore, groundwater sample analysis for TPH-m has been discontinued at the site Laboratory analysis identified dissolved TPH-d in monitoring well MW-3 at a maximum concentration of 33,000 µg/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 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 µg/L The groundwater level in MW-3 dropped to its lowest recorded depth(10 72') in April 2002