Effects of polychlorinated biphenyls, dibenzo-p-dioxins, and dibenzofurans on fish-eating birds

Abstract

Fish-eating birds are top predators at the end of the aquatic food chain. As such, they accumulate high concentrations of halogenated polycyclic aromatics like polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs). In this paper the levels and effects of these compounds on fish-eating birds are reviewed. To discuss the causal relationships between these compounds and the effects, dose–response studies in various bird species are reviewed. Neurotoxicity and effects on reproduction, embryonic respiration, mixed-function oxidase isoenzyme activities, and vitamin A and thyroid hormone levels are discussed. Using data from the literature, the lowest observed effect levels are calculated for different end points, and differences in sensitivity between the species are discussed.Key words: fish-eating birds, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, reproductive impairment, cytochrome P-450.