| Research Abstract |
Polychlorinated biphenyls (PCBs) are very similar compounds to polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofuran (PCDFs), which cause chloracne or reproductive trouble to human body. It has been clear that PCBs are highly toxic and is an environmental pollutant, which transfers to milk and fish and is taken orally in human body through food chain. Especially, in recent years, coplanar PCBs (esp.three kinds of non-ortho-coplanar PCBs, or 3,3', 4,4'-tetraCB,3,3', 4,4'-pentaCB and 3,3', 4,4'-hexaCB) have been found very similar to chlorinated dioxins and dibenzofuran in the structure and in the toxic reaction system. Further investigation is our urgent matter. This study mainly shows analyzes of the behavior in combustion, the formation system and the leaching behavior from incinerator residues of chlorinated organics including coplanar PCBs. In 1996 and 1997, the following investigations were carried out ;
1996 : (1) Waste organic solvent from research and development activities
(2) Coplanar PCBs behavior on the process of incineration
1997 : (3) Possibility of de novo synthesis by carbon structure and chlorine
(4) Leaching behavior from incinerator residues
These analyzes detected coplanar PCBs in MSW incinerator residues which were considered the biggest source of PCDDs/PCDFs generation. The level was 10% of the total amount of dioxins and dibenzofuran in 2,3,7,8-TCDD toxicity equivalent concentration, and was 5 to 10% of total PCB.Whether de novo synthesis happens or not was confirmed by heating fly ash. The result showed the possibility that de novo synthesis occurred on the process of solid phase reaction of fly ash. In incinerator residues, coplanar PCBs were detected, as well as dioxins. Surfactant agents being added, the leaching concentration of these toxic compounds raised. On the whole process of combustion, it is estimated that PCBs would be produced by "Trace Chemistries of Fire" similar to dioxins.
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