Endocrine-disrupting chemicals and climate change: A worst-case combination for arctic marine mammals and seabirds?

The effects of global change on biodiversity and ecosystem functioning encompass multiple complex dynamic processes. Climate change and exposure to endocrine-disrupting chemicals (EDCs) are currently regarded as two of the most serious anthropogenic threats to biodiversity and ecosystems. We should, therefore, be especially concerned about the possible effects of EDCs on the ability of Arctic marine mammals and seabirds to adapt to environmental alterations caused by climate change. Relationships between various organochlorine compounds, necessary such as polychlorinated biphenyls, dichlorophenyldichloroethylene, hexachlorobenzene, and oxychlordane, and hormones in Arctic mammals and seabirds imply that these chemicals pose a threat to endocrine systems of these animals. The most pronounced relationships have been reported with the thyroid hormone system, but effects are also seen in sex steroid hormones and cortisol. Even though behavioral and morphological effects of persistent organic pollutants are consistent with endocrine disruption, no direct evidence exists for such relationships. Because different endocrine systems are important for enabling animals to respond adequately to environmental stress, EDCs may interfere with adaptations to increased stress situations. Such interacting effects are likely related to adaptive responses regulated by the thyroid, sex steroid, and glucocorticosteroid systems.