Congener-specific patterns and toxic assessment of polychlorinated biphenyls in resident and migratory birds from Southern India and Lake Baikal in Russia

Concentrations of polychlorinated biphenyls (PCBs), including non-, mono-, and di-ortho congeners, were determined in migratory and resident birds collected from India and Lake Baikal in Russia. In the 11 different species examined, total PCBs concentrations were in the range of 11-4500 ng/g (wet wt). IUPAC 105, 118, 138, 153, and 180 were the predominant congeners in almost all the birds. White-cheeked tern collected from India and common tern collected from Lake Baikal showed high PCBs concentrations of 4400 ng/g (wet wt) and 4500 ng/g (wet wt), respectively, and accumulated relatively high ratios of penta-CBs (IUPAC 118, 105, 99). Toxic equivalents (TEQs) of non- and mono-ortho PCB congeners in birds collected from India and Lake Baikal were in the range of 1.5-56 and 2.8-370 pg/g wet wt, respectively. Toxic assessment results led by calculated TEQs of the transfer to eggs from female birds revealed that TEQs in most of migratory and resident birds were comparable to the lowest observable effect level (LOAEL) of chicken which is a highly sensitive species against dioxin-like compounds. Calculated transfer TEQs to eggs of common tern collected from Lake Baikal in autumn, however, exceeded the LOAEL of CYP1A induction in bald eagle embryos and ED50 of that in pheasant embryos, suggesting that embryo toxicity by coplanar PCBs in some avian species breeding in Lake Baikal is possible.