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was detected above the PQL in the sample from downgradient surface water station <br />FSW-1. Confirmation samples will be collected in August 2008 for each COC measured <br />above the PQL, including of 2,4,5-T at well -2A, sulfide in well MW -24, and <br />cyanide at surface water station FSW-l. <br />As shown in the table below, concentrations of the following metal analytes exceeded a <br />state or federal maximum contaminant level (MCL). <br />CONSTITUENT <br />MCL <br />Forward Unit DMP Monitoring Wells <br />MW-lA MW -2A MW -3A MW -15 MW -18 <br />METALS (mg/1) <br />an anese <br />1 0.05 <br />2.000 <br />Nickel <br />1 0.1 <br />0.190 <br />0.600 0.340 1 0.240 <br />As indicated, the most commonly exceeded MCL was nickel. Historically, nickel has <br />been identified at similar concentrations in both upgradient and downgradient wells, <br />suggesting that these elevated nickel concentrations may be naturally occurring. In <br />addition, manganese exceeded its MCL at well MW -2A. Elevated manganese <br />concentrations are common around unlined landfills where biodegradation activities <br />promote an oxygen -poor (i.e. reducing) groundwater environment resulting in low <br />dissolved oxygen (DO) levels. At a distance from the landfill, DO concentrations <br />increase and manganese oxidizes resulting in lower amounts of dissolved manganese in <br />groundwater. Considering these conditions and the fact that metals have fairly limited <br />mobility in soil and groundwater, especially in neutral pH environments like the Forward <br />Landfill site (Fetter, 1993), the MCL exceedances do not appear to be related to a release <br />from the landfill. <br />3: '1 <br />Groundwater quality conditions beneath the Forward Unit during the second quarter 2008 <br />monitoring period are generally similar to those observed in previous monitoring periods. <br />During the second quarter 2008 monitoring period, seven new historical intrawell <br />maximum values were measured in samples collected from groundwater monitoring <br />wells. Estimated trace -level VOCs were measured in wells MW -14 and MW -21. CLs <br />were exceeded for one or more monitoring parameters in samples from 12 wells. In <br />accordance with the RPCMP, seven wells with exceedances of CLs that are potential <br />impact constituents will be resampled in August 2008 (during the third quarter 2008 <br />sampling event), and a second independent sample will be collected in September 2008. <br />The results of the two retests will be submitted to DTSC and RWQCB under separate <br />cover. Historically, similar exceedances of inorganic CLs have been measured and <br />verified in samples collected from DMP monitoring wells at the Forward Unit, followed <br />by no release demonstrations (NRDs), which have concluded that the inorganic CL <br />exceedances are likely the result of naturally occurring conditions and therefore not <br />indicative of a release from the Forward Landfill. <br />During the second quarter 2008 monitoring period, methane concentrations did not <br />exceed the regulatory limit of five percent in perimeter soil -pore gas probes at the <br />Forward Unit. Forward continues to install additional landfill gas extraction wells (as <br />D:\2008_0010\FA_2Q08.doc <br />8 Geologic Associates <br />