ARCHIVED REPORTS_XR0004477 - Laserfiche WebLink

Home Browse Search

I ' 2005 3rdQuarter Groundwater Report • Frontier Transportation,Inc. ' December 5, 2005 Page 4 ' MTBE, tertiary butyl alcohol (TBA), di-isopropyl ether(DIPS), ethyl tertiary butyl ether(ETBE) and tertiary amyl methyl ether(TAME) using EPA method $260. 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 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 pg/L The groundwater level in MW-3 dropped to its lowest recorded depth(10.72') in April 2002 Monitoring well MW-3 was abandoned in May 2002. Replacement well MW-3R identified no detectable concentrations of dissolved TPH-d No other detectable concentrations of dissolved TPH-d were identified from laboratory analysis in any of the wells sampled since then, which includes the second quarter 2004 sampling episode Therefore, groundwater sample analysis for TPH-d has been discontinued at the site. 1 Historical groundwater monitoring results have identified TPH-g concentrations above 1,000 pg/L in MW-1, MW-3 and MW-3R. Dissolved TPH-g concentrations in MW-1 had attenuated from 1,800 µg/L in August 1996 and remained under 50 µg/L from January 2000 to March 2005 (See Figure 6 for dissolved TPH-g over time in MW-1) Maximum dissolved TPH- g concentrations were identified in March 1998 as 42,000 gg/L in MW-3, which was the { ' shallowest recorded groundwater depth in that well Since then, dissolved TPH-g concentrations attenuated to a low of 100 µg/L. The last groundwater sample collected from MW-3 in April 2002 prior to abandonment detected dissolved TPH-g as 9,750 gg,/L The maximum dissolved ' TPH-g concentration in MW-3R was 3,790 µg/L in October 2002 Since then, the dissolved TPH-g levels have decreased over time to lower levels ' Groundwater collected in September 2005 from thirteen(13)monitoring wells identified 1