Chlorinated/brominated organic pollutants in aquatic birds and mammals: species- and food web-specific fate, biotransformation, trends and thyroid system effects

越来越多的证据表明，接触人造环境化学品，特别是在环境中持久并生物积累的有机化合物，会对暴露在环境中的野生动物和人类造成不利影响。其中许多环境化学品可以被描述为有机卤素，因为它们含有氯、溴或氟原子。“遗留”有机卤素污染物包括多氯联苯和许多有机氯农药。在水生野生动物的组织中发现了许多新的或“新兴”的化学物质，包括溴化阻燃剂(BFR)，如多溴联苯醚(PBDEs)。然而，在环境中有许多当前使用的溴化阻燃剂是未知的。所有生物体都有酶，可以调节外来化学物质的新陈代谢或生物转化，这意味着促进它们从体内消除。尽管对“遗留”和“新兴”有机卤素的了解有所增加，但MUMB仍然不清楚生物转化(氧化过程和脱溴)如何决定水生野生动物在组织、物种、食物链和种群特定水平上的命运、环境化学和含羟基(OH-)代谢物的形成。在氯化和溴化有机卤素的情况下，可能会形成含有羟基的代谢物(例如，羟基多氯联苯和羟基多溴二苯醚)并保留在动物体内，尽管对这些代谢物在食物网中的累积情况仍知之甚少。···然而，对野生动物体内含有羟基的有机卤素的内分泌活性的研究还很有限。拟议研究计划的总体目标是扩大和开展关于生物转化对五大湖和北极水环境中模式水生物种和食物网中有机卤素和含OH代谢物的时空动态和分布的作用、生理命运和动力学的作用以及对甲状腺系统的影响的相互作用的新研究。

There is increasing evidence that exposure to man-made environmental chemicals, particularly organic compounds that persistent and bioaccumulate in the environment, cause adverse effects in exposed wildlife and humans. Many of these environmental chemicals can be described as organohalogens as they contain the atoms chlorine, bromine or fluorine. "Legacy" organohalogen contaminants include polychlorinated biphenyls (PCBs) and numerous organochlorines pesticides. There are numerous new or "emerging" chemicals being found in the tissues of aquatic wildlife including brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). However, there are numerous current-use BFRs unknown in the environment. All organisms possess enzymes that can mediate the metabolism, or biotransformation of foreign chemicals, which is meant facilitate their elimination from the body. Although the understanding has increased for bothh "legacy" and "emerging" organohalogens, mucb remains unknown on how biotransformation (oxidative processes and debromination) determines the fate, environmental chemistry and formation of hydroxyl- (OH-) containing metabolites at the tissue-, species, food web- and population-specific levels in aquatic wildlife. In the case of chlorinated and brominated organohalogens, formation of OH-containing metabolites can occur (e.g., OH-PCBs and OH-PBDEs) and be retained in the animal although there remains little understanding of how accumulative these metabolites are in food webs. OH-PCBs, OH-PBDEs and related compounds also possess the ability to act as hormones (e.g., thyroid), and thus affect hormone-dependent functions in an exposed animals. However, research is limited on endocrine activity of OH-containing organohalogens in wildlife species. The overall objective of the proposed research program to expand and undertake new research on the role of biotransformation on spatial/temporal dynamics and distribution, physiological fate and dynamics, and interaction of effects on the thyroid system, of organohalogens and OH-containing metabolites in model aquatic species and food webs in the Great Lakes and Arctic aquatic environments.