Dechlorination-Controlled Polychlorinated Dibenzofuran Isomer Patterns from Municipal Waste Incinerators

The ability to predict polychlorinated dibenzofuran (PCDF) isomer patterns from municipal waste incinerators (MWIs) enables an understanding of PCDF formation that may lead to preventive measures. This work develops a model for the pattern prediction, assuming that the chromatograph peak ratios relative to the total four heptachloro-dibenzofuran (H7CDF) isomers are determined by position-specific dechlorination kinetics from an octachloro-dibenzofuran (O8CDF) parent to H7CDFs and that these probabilities can subsequently predict the relative concentrations of lower chlorinated isomers. Agreement of PCDF isomer patterns between the model and sampled data from eight MWIs is consistent with formation of tetrachloro-dibenzofurans to H7CDFs by dechlorination from an O8CDF parent. The application of the analogous theory to predict isomer patterns of poly- chlorinated dibenzo- p -dioxins (PCDDs) did not provide any significant results, which implies that the formation mechanism of PCDDs is controlled by other factors such as condensation of precursors and further chlorination. This method can be a fundamental basis to develop a prediction model for total PCDFs emission and toxic equivalent values.