A Taiwanese study of 2,3,7,8-substituted PCDD/DFs and coplanar PCBs in fly ashes from incinerators

Fly ashes from municipal solid waste (MSW), medical waste (MW), and electrical power plant (EPP) incinerators are analyzed for dioxin-like compounds (DLCs), including seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (2,3,7,8-substituted PCDD/DFs) and three coplanar polychlorinated biphenyls (Co-PCBs) of PCB 77, 126 and 169. The 2,3,7,8-tetradidioxin toxic equivalent (TEQ) values in fly ashes arranged in increasing order is 0.3, 2.1, 13.9 and 29.3 ng/g from EPP, large MSW, MW and small MSW incinerators. The contribution to total TEQ from Co-PCBs ranges from 4 to 25%, indicating that small MSW and MW incinerators are potential Co-PCBs contaminating sources. Fly ashes from small MSW and MW incinerators in Taiwan should be treated as hazardous materials. In the future, priority should be given to the construction of MSW incinerators with large burning capacities. (C) 1998 Elsevier Science B.V.