Environmental occurrence and potential toxicity of planar, mono-, and di-ortho polychlorinated biphenyls in the biota
- State Univ. of New York, Albany, NY (United States)
Coplanar PCBs without ortho-chlorine substituents and semicoplanar PCBs with one ortho-chlorination are stereochemically similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and, because of this similarity, exert biochemical activity and toxicity to biota comparable to that of TCDD. Four non-ortho-, eight mono-ortho-, and two di-ortho-chlorinated congeners have been determined in insect larvae, fresh water and salt water mussels, fish, mallard duck, seals, and in human milk and adipose tissue. The PCB congeners are separated from the remainder of PCBs by activated carbon chromatography or HPLC on porous graphitic carbon followed by gas chromatography with electron capture detection. PCB toxic equivalency factors (TEFs) (1) recommended by WHO for 3 non-ortho, 8 mono-ortho and 2 di-ortho PCBs and a TEF for congener 81 (3,4,4{prime},5-tetrachlorobiphenyl) suggested by Harris et al. from AHH induction in rainbow trout (2) were used for calculation of the contribution to dioxin-like toxicity to each life form. In all the biota examined, PCB congener number 126 was the major contributor to PCB toxic equivalents (TEQs), followed by congener numbers 118, 114, 156, and 105. The ability to separate out planar PCBs from the majority of PCBs has allowed the use of TCDD toxicity equivalence to compare the relative dioxin-like potency of PCB residues in various species from 12 different locations.
- OSTI ID:
- 398209
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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