The role of metals in dioxin formation from combustion of newspapers and polyvinyl chloride in an incinerator

Newspapers impregnated with NaCl mixed with various chloride metals (CuCl 2, MgCl 2, MnCl 2, FeCl 3, NiCl 2, and CoCl 2) and electric wire coated with polyvinyl chloride (PVC) were combusted in a well-controlled incinerator. Exhaust gas samples collected at the outlet of the incinerator were analyzed for dioxins (PCDDs, PCDFs, and coplanar PCBs) by gas chromatography/mass spectrometry. The amount of total dioxins formed from newspaper samples ranged from 34.2 ng/g (with NaCl + CoCl 2) to 67.0 ng/g (with NaCl + CuCl 2). PCDFs composed 88–94% of the total dioxins formed in the exhaust gases. The highest levels of PCDF isomers obtained were Cl 3-CDF from the sample with NaCl + CuCl 2 (14.8 ng/g), Cl 2-CDF from the sample with NaCl + MgCl 2 (12.3 ng/g), and Cl 1-CDF from samples with NaCl + MnCl 2 (12.6 ng/g), with NaCl + FeCl 3 (11.8 ng/g), and with NaCl + NiCl 2 (13.3 ng/g), and with NaCl + CoCl 2 (8.62 ng/g). The total of Cl 4–8-CDDs comprised 76–88% of the total Cl 1–8-CDDs. In particular, Cl 7-CDDs had the highest levels except for the sample with NaCl + NiCl 2. Total dioxins formed from samples of electric wire coated with PVC and PVC alone were 38.3 ng/g and 112 ng/g, respectively, suggesting that the presence of copper reduced dioxin formation.