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Draft Environmental Impact Report Page IV.F-17 Forward Inc. Landfill Expansion Well AMW-1 on the northwest side of the Austin unit showed the maximum concentration of all the monitoring wells in the Q2-2008 monitoring event with 25 ug/L PCVER and 6.7 ug/L PCE. Several VOCs were also found in the downgradient monitoring wells,including the wells AMW-13 andAMW-14 approximately 1.600 feet downgradient from the extraction wells EW-1 and EW-2. The PCE concentration was reported in Q1-2008 at 25 and 18 ug/L in wells AMW-13 and 14, respectively. Evaluation monitoring program was implemented in three phases to determine the vertical and horizontal extent of contamination. Phases I and II confirmed VOC impacts along the entire downgradient edge of the landfill and in the first encountered water bearing zone. Phase III indicated the chlorinated hydrocarbon impacted groundwater extends laterally downgradient of the edge of the landfill. Based on the Q2-2008 dataset the water quality impacts at the Forward Landfill are currently limited to one well north of the closed Class I WMU-A that show trace (<1 pg/L) detectable concentrations of the VOCs PCE,TCE, and 1,1-DCE in wells MW-10. At the Austin Landfill AMW-1, AMW-10, and AMW-11 and AMW-19, the principal VOC analyte, PCE, ranged from a concentration of 3.3 ug/L to 25 ug/L. The locations of the wells are shown in Figure IV.F-1, with all the wells with detectable VOCs located along or north of the landfill border. The Forward Landfill leachate collection system appears to have integrity. Table IV.F-1 shows the key VOC concentrations detected in 1999 versus the 2008. This illustrates the effectiveness of the VOC reduction within that timeframe at the common well with the highest concentration in 1999. This is important in projecting forward the potential effectiveness of current remedies to handle the additional landfilling proposed by the expansion. The key maximum VOC concentrations reported in the downgradient (north of the former Austin Road Landfill) monitoring points in 1999 include: PCE (210 ug/L);TCE (39 ug/L); and DCE (36 ug/L) and VC (11 ug/L). This same well in 2008 had a reported PCE(0.78 ug/L), no detectable TCE(<0.19 pg/L), DCE (0.51 jug/L) and no detectable VC (<0.34). Table IV.F-1 Maximum Key VOC Concentrations Reported in 1999 (Well MW-11) # Compared to Drinking Water Standards and Title 27 Cleanup Goals JE,I E E `x [dE F E € 'c'.ois3E 'tP yr } Maximum E Mazimu Drxnl.lcing, , ; Concentrations E Concentrattion Watex i Water,Quali E;. �� a v a €EE E w �' , E 1 SEE - L� 'EErE[ StaIldard Edi?3 s Obecta,ves b Key VOC Detected ;, Detected 19}9 Detected 20Q8 ( g/L) ( gl�) i ;` Tetrachloroethene (PCE) 210 0.78 5.0 0.06 Trichloroethene (TCE) 39 <0.19 5.0 0.7 cis-l,2-dichloroethene 36 <0.32 6.0 6.0 (cis-1,2-DCE) Vinyl chloride NO 11 <0.34 0.5 0.5 The well AMW-11, (and nearby wells MW-10, MW-13, and MW-14) are screened across the 80 to 104-foot interval sand layer depth. The maximum concentration of VOCs in 2008 were dected in wells MW-13 (at 25 ug/L PCE and 7.1 ug/L TCE) and well MW-14 (at 18 ug/L PCE and 1.3 Pg/L TCE).