A Critical Review of Bioaccumulation and Biotransformation of Organic Chemicals in Birds

Abstract A literature review of bioaccumulation and biotransformation organic chemicals in birds was undertaken, aiming to support scoping prioritization future research. The objectives were characterize available bioaccumulation/biotransformation data, identify knowledge gaps, determine how extant data can be used, explore the strategy steps forward. An intermediate approach balanced between expediency rigor taken given vastness literature. Following a critical > 500 peer-reviewed studies, 25,000 entries 2 million information bytes compiled on 700 compounds for ~ 320 wild species 60 domestic breeds birds. These organized into themed databases , field survey microsomal enzyme activity metabolic pathway bird taxonomy diet . Significant gaps identified all at multiple levels. Biotransformation characterization largely fragmented over metabolite/pathway identification or kinetics. Limited kinetic constrained development an avian model. substantial shortage vivo kinetics has been observed as most reported rate constants derived vitro. No metric comprehensively captured key contaminant classes chemical groups broad-scope modeling biotransformation. However, metrics such biota-feed accumulation factor, maximum transfer total elimination constant more readily usable benchmarking than other reviewed parameters. Analysis demonstrated lack shorebirds, seabirds, raptors. In study birds, this revealed need greater diversity, measurements environmental media, basic biometrics exposure conditions, tissues/matrices sampling, further exploration Limitations classical current research strategies used studies also discussed. Forward-looking proposed: adopting roadmap investigations, integrating existing biomonitoring gap-filling with non-testing approaches, improving reporting practices, expanding sampling scopes, bridging models theories, exploring via genomics, establishing online repository.