TOXIC COMBUSTION BY-PRODUCTS FROM THE INCINERATION OF CHLORINATED HYDROCARBONS AND PLASTICS

Polyvinylidene chloride and polyvinyl chloride were pyrolyzed in a thermal gravimetric analyzer and by-products were collected for chemical analysis and bioassay. Trichloroethylene was also burned in a laminar diffusion flame of methane with varying concentrations of the chlorinated compound. Soot particulates collected on filters and post-flame gases collected on sorbent tubes were extracted and analyzed using gas chromatography-mass spectrometry. Extracts were evaluated for potential toxicity using an in vitro hyperkeratinization bioassay that is sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Chemical analyses identified polycyclic aromatic hydrocarbons and chlorinated PAHs as the major pyrolysis products. Products generated from the pyrolysis of both polymers yielded definite positive bioassay responses. Most of the products obtained from the trichloroethylene flame were associated with soot particles emitted from the flame. A series of chlorinated aromatic compounds, including hexachlorocyclopentadiene and chlorinated benzenes, polycyclic aromatics, and fulvalenes were identified as major products. Dichloromethane extracts of the soots elicited a positive bioassay response.