ARCHIVED REPORTS_1988 - Laserfiche WebLink

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KLEINFELDER in the fill, or they may reflect the presence of certain kinds of bacteria that are digested in the aggressive freon extraction processes employed by Chemwest Analytical Laboratory. All seven samples were submitted for analysis of metals. Twenty-five metals were included in this analysis. The analysis procedure consisted of first digesting a portion of the sample using nitric acid, followed by hydrogen peroxide, followed by hydrochloric acid. This digestion procedure breaks down the soil and waste, including pieces of metallic slag contained in the waste. The digestate is then filtered and analyzed for metal content. Of the 25 metals quantified in the analysis, 5 were not detected at concentrations above the reporting limit in any of the seven samples submitted. These five metals are; thallium, iselenium, molybdenum, cobalt, cadmium, and beryllium. Two other metals, mercury and nickel,were detected at, or just above, the reporting limit in one or two samples.` Of the 18 metals detected in the seven samples, 8 metals were detected in slightly to significantly higher concentrations in the samples from the fill material. These eight metals are: barium, calcium, chromium, copper, iron,jead, manganese, and zinc. Lead was reported at concentrations exceeding the established Total Threshold Limit Concentration (TTLC) of 1,000 mg/kg in two of the samples from the fill. These two samples were resubmitted to the laboratory for a Waste Extraction Test (WET). Analyzed for WET methodology, at a pH of 5.0, both samples contained concentrations of soluble lead that exceed the Soluble Threshold Limit Concentration (STLC) of 5 mg/l. However, no detectable concentrations of lead were reported in the samples from the soil/waste interface or from the vadose zone below the fill. This is likely an indication that the landfill is not acidic, and that the lead is not as soluble under the higher pH conditions expected in the landfill. There is an apparent conflict in results: the fill appears to contain soluble lead, yet none of that lead can be found in the vadose zone. Soluble lead, at the concentrations found using the WET, should have migrated to the vadose zone by this time. Ample time has elapsed since closure of the landfill (33 years) for this process to have ocurred. This conflict can be resolved by comparing the leaching potential of municipal leachate and the WET. Table 3 contains the results of such a study conducted at the Oak Ridge National Laboratory. The WET is much more aggressive than the leachate found in landfills. With respect to lead, the WET will mobilize 1000 times more lead than municipal leachate. Assuming that the WET is 1000 times more aggressive than municipal leachate, then under the natural 137-88-1663 14