Isomer-specific analysis of PCBs including toxic coplanar isomers in canned cod livers commercially processed in Poland.

Concentrations of highly toxic coplanar non-ortho (IUPAC Nos. 77, 126 and 169), mono-ortho (IUPAC Nos. 60, 105, 118 and 157), di-ortho (IUPAC Nos. 128, 139 and 170) members and 73 other isomers and congeners of PCBs were determined in canned cod livers W 9tróbka rybna po Kaukasku produced by a company in Gdańsk, Poland in early 1990. Total PCB concentrations ranged over 1.2-2.6 micrograms/g wet mass. Concentrations of ten toxic coplanar PCBs (IUPAC Nos. 77, 126, 169, 60, 105, 118, 156, 128, 138, and 170) were found to be in the range of 360 to 690 ng/g wet mass and their TCDD TEQs were 370 to 530 pg/g for aryl hydrocarbon hydroxylase and from 290-430 pg/g for ethoxy-resorufin O-deethylase. Among these toxic congeners IUPAC No. 126, which showed 84% of total TEQ values, imparted most significant toxic threat. Considering these observations, canned cod livers are likely to pose concern to human health since they exceed the tolerance limit of total PCBs (2.0 micrograms/g for edible parts of fishery products) and contain significant residue levels of toxic coplanar PCBs.