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2002 2"d Quarter Groundwater Report Frontier Transportation 0902_182 September 3, 2002 Page 3 ' 4.0) QUARTERLY GROUNDWATER SAMPLE RESULTS ' On June 24, 2002, BEII contracted Del-Tech to collect groundwater samples from monitoring wells MW-I through MW-13 for laboratory analysis. A broken down truck and trailer were over monitoring well MW-11, therefore it was not sampled this episode. Groundwater parameters (pH, temperature, and conductivity) were measured before, during, and after well purging (See Appendix A for Monitoring Well Field Logs). Groundwater samples were analyzed for TPH-d, TPH-g, BTEX, and MTBE using EPA methods 8015 modified for ' diesel, 8015 modified for gasoline, 8020 for BTEX, and 8260 for MTBE, respectively. Laboratory analysis results for all monitoring episodes are presented in Table 1. Recent analytical reports are included as Appendix B. ' 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. BEII concludes 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. BEII, therefore, has discontinued groundwater sample analysis for TPH-m at the site. Laboratory analysis sis identified dissolved TPH-d in monitoring well MW-3 at a maximum concentration of 33,000 pg/L, however it was reported as TPH-d and TPH-m combined. Since ' then. dissolved TPH-d concentrations in MW-3 have attenuated from >6,000 µg/L in December 2000 to non-detect in April, August, and November of 2001. None of the remaining ten ' monitoring wells identified detectable concentrations of TPH-d either. The groundwater level dropped in the well by approximately 0.5 feet between November 2001 and April 2002. April 2002 groundwater analysis results identified dissolved TPH-d exclusively from MW-3 as 14,200 ' pg/L. No other detectable concentrations of dissolved TPH-d were identified from laboratory analysis since then. Groundwater analysis for TPH-d will continue to be performed for the site. ' Historical groundwater monitoring results have identified TPH-g concentrations above 1,000 µg/l, in MW-1 and MW-3 only. Maximum dissolved TPH-g concentrations were identified in March 1998 as 42,000 pg/L in MW-3, which was the shallowest recorded groundwater depth in that well. Since.then,.dissolved.TPH-g concentrations have attenuated_ - from the maximum. Dissolved TPH-g concentrations in MW-1 have attenuated from 1,800 pg/L in August 1996 and remained under 50 pg/L since January 2000. Groundwater collected in June 2002 from twelveroundwater monitoring wells g g 1