Levels, trends, and health effects of dioxins and related compounds in aquatic biota

Abstract

The objective of this chapter is to review current knowledge of the levels, trends, and health effects of dioxins and dioxin-like compounds (DLCs) including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and polychlorinated biphenyls (PCBs) in aquatic biota, with a special focus on high trophic level species. DLCs can be released into the environment through storm runoff, air deposition, wastewater discharge from industrial processes, and leaching from landfills. To characterize their influences in biota, studies examining levels and trends of DLCs from invertebrates to vertebrates from several regions (the Arctic, North America, Asia and Europe) are reviewed. Over several decades, such studies have helped elucidate the accumulation, possible sources, metabolic fate, as well as the potential health effects of dioxins and DLCs in aquatic biota. The trophic transfer of these compounds via bioaccumulation and biomagnification can result in higher concentrations in top predators, and a wide range of toxic effects (e.g., endocrine disruption, developmental and reproductive effects, and immunotoxicity) has been reported in diverse species, especially those occupying high trophic levels, e.g., marine mammals. Because of their high trophic position and widespread distribution, marine mammals are valuable sentinel species for PCB and DLC contamination, providing insights into possible sources, transport pathways, and the distribution of these compounds on a global scale. Populationlevels effects related to contaminant-induced reproductive impairment and disease have been reported in wildlife inhabiting polluted regions, and the occurrence of mass mortalities among marine mammal populations has been linked to high body burdens of immunotoxic compounds, notably PCBs. Many affected populations have never recovered to their original levels. For many contaminant-stressed populations, the added stress of climate change is exacerbating the problem, causing shifts in food webs and increasing both the distribution and toxicity of POPs in coastal and oceanic environments. Critical data gaps and future research challenges are highlighted as areas that require further study. © Springer International Publishing Switzerland 2016.