Formation of polychlorinated naphthalenes on fly ash

During the oxidative degradation of carbonaceous material on fly ash, besides PCDD/F, PCPh, PCBz, PCB, polychlorinated naphthalenes (PCN or ClxN) are formed. Thermal experiments were carried out with fly ash from a municipal waste incinerator at 300°C and reaction times of 0.5 h up to 4 h. For the study an analytical method using GC/MS was developed similar to that, used in dioxin-analysis. Isomer specific identification of chloronaphthalenes formed on fly ash was realized by comparison of ClxN from technical PCN-mixtures (Halowax®). For quantification of the PCN formed, 13C- labelled PCB-standards were used as internal standards because no 13C- labelled PCN-compounds were available. Both, technical PCN-mixtures and PCN formed on fly ash show a characteristic pattern of CINN-congeners according to their difference in formation. Cl2N---Cl5N were formed most and Cl1N---Cl3N were also found in the gas phase in high amounts. A single isomer 1,2,3,5,6,7-Cl6N, known as a strongly bioaccumulating and toxic PCN, is formed in higher amounts together with 1,2,3,4,6,7-Cl6N.