ARCHIVED REPORTS_2008_20 - Laserfiche WebLink

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Estimated trace-level VOCs were measured in wells MW-10 and MW-14; while one VOC (PCE)was measured above its PQL in well MW-14. In addition, the SVOC bis(2- ethylhexyl)phthalate(a suspected laboratory contaminant)was measured at a trace concentration in well MW-24. CLs were exceeded for one or more monitoring parameters in samples from 12 wells. In accordance with the RPCMP, seven wells with exceedances of CLs that are potential impact constituents will be resampled in February 2009 (during the first quarter 2009 sampling event), and a second independent sample will be collected in March 2009. The results of the two retests will be submitted to DISC and RWQCB under separate cover. Historically, similar exceedances of inorganic CLs have been measured and verified in samples collected from DMP monitoring wells at the Forward Unit, followed by no release demonstrations (NRDs), which have concluded that the inorganic CL exceedances are likely the result of naturally occurring conditions and therefore not indicative of a release from the Forward Landfill. On behalf of Forward, GLA has submitted a request to the DTSC to update the CLs for the Forward Unit. During the fourth quarter 2008 monitoring period the leachate results are generally similar to those observed historically. During the fourth quarter 2008 monitoring period, eight dissolved metal constituents were measured with six above their PQL; nine VOCs were measured with eight above their PQL; and eight SVOCs were measured with six above their PQL in the leachate sample collected during the fourth quarter 2008 monitoring period. No herbicides or pesticides were detected in the leachate sample. The results of the annual leachate sample indicate that there was one potentially new COC (2,4-dichlorophenol). Verification testing of leachate for this SVOC (2,4- dichlorophenol) will be performed in May 2009. During the fourth quarter 2008 monitoring period, methane concentrations did not exceed the regulatory limit of five percent in perimeter soil-pore gas probes at the Forward Unit. Forward continues to install additional landfill gas extraction wells (as needed), and makes regular adjustments to the landfill gas extraction system to optimize efficiency of the landfill gas extraction system. 3.0 AUSTIN UNIT 3.1 WATER QUALITY MONITORING 3.1.1 Sampling and Laboratory Analyses During the fourth quarter 2008, depth-to-water measurements were recorded in the groundwater monitoring wells on November 10 and 11, 2008 and the Austin Unit's DMP and CAP groundwater monitoring wells were sampled by ATC between November 10 and 12, 2008. Both surface water stations were inspected on November 12, 2008 and reported dry. A single sample set was collected from each sample point with sufficient liquid and submitted to BC for analysis of the parameters stipulated in RWQCB Order No. R5- DA200s_ooio\Fn_4Qos.aoc GeoLogic Associates