The distribution, exposure dynamics and toxic significance of 42 polychlorinated biphenyls (including three coplanar congeners), in biota and sediment from the Western Basin of Lake Erie.

Polyclorinated biphenyls are ubiquitous pollutants which are associated with wasting syndrome, reproductive problems, teratogenicity and mortality in wildlife (Borgmann et al. 1990; Kubiak et al. 1989). There are 209 PCB congeners which differentially partition, bioaccumulate and degrade in the environment. It is important to analyze the exposure dynamics of individual PCBs, as congener toxicity and persistence varies considerably. This study examined the dynamics and distribution of 42 congeners in sediment and biota from the Western Basin of Lake Erie. The non-ortho substituted congeners IUPAC #77, #126 and #169 were quantified, and their concentrations were examined in various trophic levels. The AHH induction potency of each coplanar PCB was determined using the AHH assay on rat (H4IIE), mouse (Hepa Clone 9) and human (Hep G2) cell lines. The PCB dynamics in the food web sampled were more complex than predicted by thermodynamic partitioning. Tetrachlorinated biphenyls were found to dominate lower trophic level samples; whereas, predatory animals exhibited much higher levels of hexa- and heptachlorinated biphenyls. The composition of PCB congeners was different for each trophic level, while concentrations of total PCB (equal to the sum of 42 congeners) increased with increasing trophic level. There were few differences in the distribution of ortho-substituted PCBs among species\u27 tissues. Coplanar PCBs were found in Lake Erie species. Residues of congener #126 and #169 were detected in herring gull eggs and in benthic organisms only, whereas #77 was present in all samples. There were significant differences in the partitioning of coplanar PCBs between muscle, liver and egg tissues for all fish species sampled. The proportion of total PCB congeners that were coplanar decreased with increasing trophic level. The AHH assay indicated that congener #126 induced Hepa Clone 9 mouse cells more than #77 or #169, and slightly less than TCDD. The H4IIE and Hep G2 cells did not give consistent results; however, the coplanar PCBs did induce AHH activity in both cell lines. Experiments with tissue extracts gave very low levels of enzyme activity, while chemical combinations induced lower activity levels than anticipated. This may have been the result of competitive inhibition by less potent inducers such as congener #77.Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .K67. Source: Masters Abstracts International, Volume: 32-06, page: 1585. Advisers: D. Haffner; M. Dufresne. Thesis (M.Sc.)--University of Windsor (Canada), 1993