ARCHIVED REPORTS_XR0004497 - Laserfiche WebLink

Home Browse Search

1 20032 d Quarter Groundwater Report Frontier Transportation August 6, 2003 ' Page 3 excavation backfill material, which was coarser than the native soil The permeability difference ' between the backfill material and native soil can cause groundwater to accumulate within the backfill material as it flows in the downgradient western direction Historic groundwater data identified a west or southwest flow beneath the site ' 4.0 QUARTERLY GROUNDWATER SAMPLE RESULTS ' On June 26, 2003, BEII contracted Del-Tech to collect groundwater samples from monitoring wells MW-1 through MW-13 for laboratory analysis 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, TPH-m, BTEX, and MTBE using EPA methods 8015 modified for diesel 8015 modified +� for gasoline, 8015 modified for motor oil, 8020 for BTEX, and 8260 for MTBE, respectively J4 t 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 , d exclusively Maximum concentrations of dissolved TPH-m were identified in MW-3 as 33,000 Gam p� - n/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 identified dissolved TPH-d in monitoring well MW-3 at a maximum Y 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 have 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 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 2003 sampling episode Groundwater analysis for TPH-d will ' continue to be performed for the site Historical groundter monitoring results have identified TPH-g concentrations above 1,000 µg/L in MW-1rid lW-3 only Maximum dissolved TPH-g concentrations were 1 3 . IL }t,0 1 1