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2006 10 Quarter Groundwater Report le Transportation, Inc. I April 28,2006 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 March 31, 2006 for laboratory analysis Monitoring wells sampled were MW-1, MW-2, MW-3R, MW-9, and MW-13 through MW-21 Groundwater parameters (pH, ' temperature, and conductivity) were measured before, during, and after well purging (See Appendix A for Monitoring Well Field Logs) ' Monitoring well MW-21 identified product sheen 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 was sampled and analyzed and found to have sigmficantly elevated dissolved MTBE and TPH-gas Dissolved MTBE was identified at 8,000 gg/L in MW-21 and 5,190 gg/L in MW-2, and dissolved TPH-gas was identified at 231,000 gg/L in MW-21 and at 6,100 gg/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 (DIPE), ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether(TAME)using EPA method 8260 Monitoring wells MW-19, MW-20 and MW-21 were also analyzed for 1,2-DCA and EDB "Laboratory analysis results for ' all monitoring episodes are presented in Table 1 Recent laboratory analytical reports are included as Appendix B ai V_--' 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 gg/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 . r Laboratoryanalysis identified dissolved TPH-d in monitoring well MW-3 at a maxunum g concentration of 33,000 gg/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 gg/L The groundwater level in MW-3 dropped to its lowest recorded depth (10 72') in April 2002