ARCHIVED REPORTS_2001_1 - Laserfiche WebLink

Home Browse Search

from wells MW-13, MW-14, and MW-21. As shown on Figure 1, the wells where VOCs were detected are located near the northeast corner of the FSL, near WMU-A and WMU- B. VOC Detections in Monitoring Well Samples 1999 and 2000 Quarterly Monitoring Events Monitoring Well No.Trace Detections No.Detections Above PQL MW-113 6 0 MW-2A 1 0 MW-10 1 0 MW-13 8 3 MW-14 19 7 MW-15 4 0 MW-16 5 0 MW-21 13 0 Inspection of the time-series plots provided in Appendix A indicates that VOCs have historically been detected sporadically and at low concentrations. The most frequently detected analytes in groundwater include: benzene, cis-l,2-dichloroethene (cis-1,2- DCE), tetrachloroethene (PCE), toluene, 1,1-dichloroethane (1,1-DCA), and 1,1,1- trichloroethane (1,1,1-TCA). Of note while VOCs have commonly been detected in wells MW-13 MW-14 and MW- 21, they were detected less often in wellsMW-2A and MW-16, which are located tbetween the 3 VOC-impacted wells (Figure 1). This may be related to aquifer heterogeneity(interfingering of coarse- and fine-grained layers) or, as discussed in Section 3, it may reflect the erratic nature of landfill gas generation at the landfill. During 1999 and 2000, the only VOCs that were detected above PQLs in monitoring well samples at the FSL were PCE, trichloroethene (TCE), and 1,1,1-TCA. As listed below, the individual detections all occurred in samples obtained from wells MW-13 and MW- 14, but did not exceed state or federal drinking water standards. VOC Detections above P Ls in Monitoring Well Samples 1999 and 2000 Quarterly Monitoring Events Well No. Analyte 1999 Detection 2000 Detection ARAR* (µg/1) MW-13 1,1,1-TCA 1.9 2 MW-13 1,1,1-TCA 1.1 2 MW-13 1,1,1-TCA 0.98 2 MW-14 PCE 2.0 5 MW-14 PCE 0.57 5 MW-14 PCE 2.8 5 MW-14 PCE 1.9 5 MW-14 PCE 0.75 5 MW-14 TCE 0.93 5 MW-14 TCE 0.72 5 • -Applicable or Relevant and Appropriate Requirements 4 Geologic Associates