Bioassay-Directed Chemical Analysis of Organic Extracts of Emissions from a Laboratory-Scale Incinerator: Combustion of Surrogate Compounds

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Abstract
A prototype/laboratory-scale rotary kiln (73 kW, 250000Btu/h) was used to examine the chemical composition and biological effects of the emissions produced when the kiln was operated under suboptimal conditions resulting from batch charging. The surrogate wastes evaluated were polyethylene (PE), polyvinylchloride (PVC), toluene (TOL), carbon tetrachloride (CCl4), PE + PVC, and TOL + CCl4. The dichloromethane-extractable organics from particles (collected on filters) and semi-volatiles (collected on XAD-2 resin) were evaluated for mutagenic activity using the Salmonella (Ames) mutagenicity assay in strain TA98 ( + S9). The mutagenic potencies (revertants/microgram of extractable organics) of the emissions ranked as follows: PE > TOL > PE + PVC > TOL + CCl4. The organic extracts from the PVC and CCl4 emissions were not mutagenic. The mutagenic emission factors (revertants/ kilogram of fuel or /megajoule of heat) for the TOL or PE emissions were similar to those for municipal waste combustors; those for PE + PVC or TOL + CCl4, were similar to those for oil or coal burned in industrial and utility boilers and power plants. These results suggest that the mutagenic emission factors may depend as much or more on the operating conditions of the incinerator than on the feed stock. Extracts were fractionated by high pressure liquid chromatography (HPLC), and each HPLC fraction was evaluated for mutagenic activity using strain TA98 (+ S9) in a microsuspension mutagenicity assay. Bioassay-directed chemical analysis was performed by subjecting selected mutagenic fractions to analysis by mass spectrometry. Various PAHs were identified in mutagenic fractions of the PE emissions. This study illustrates the value of performing both chemical and biological analyses of chemically complex combustion emissions in order to characterize the potential health effects of such mixtures.