Biotransformation and thyroidogenic effects of organochlorine and organobromine pollutants in avian and mammalian top predator sentinel species

有机氯和有机溴污染物对鸟类和哺乳动物顶级捕食者前哨物种的生物转化和甲状腺生成作用

• 批准号: 239250-2007
• 负责人: Letcher, Robert
• 金额: $ 1.26万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=394271
• 关键词: Biotransformation; thyroidogenic; effects; organochlorine; organobromine

Man-made chemicals that persist and bioaccumulate in the environment are increasingly being linked to adverse effects in wildlife and humans. Many bioaccumulative "legacy" and "emerging' contaminants found wildlife contain chlorine and bromine, including polychlorinated biphenyls (PCBs) and the brominated flame retardant (BFR) class known as polybrominated diphenyl ethers (PBDEs). An organism's ability to eliminate organohalogens and other foreign chemicals from the body is dependent on enzymes that can mediate metabolism and biotransformation. Much remains unknown as to role and significance of biotransformation (e.g., oxidative and debromination processes) in the fate and bioaccumulation of chlorinated and brominated organohalogens, which includes the formation of hydroxyl- (OH-) containing or "phenolic" metabolites, in different species and food webs, and especially in top predator wildlife. As has been shown for PCBs and PBDEs in some wildlife, biotransformation can lead to persistent OH-PCB and OH-PBDE metabolites, although there remains minimal understanding of the formation, bioaccumulation and toxicokinetics of these "second level" pollutants. OH-PCBs, OH-PBDEs, related phenolic compounds/metabolites, and debrominated products of PBDEs and current-use BFRs are "bioactive" via hormone mimicry, and can interfere with thyroid hormone-dependent functions and processes (e.g., hormone transport and enzyme-mediated inter-conversion). Endocrine (thyroid) activity and effects in relation to organohalogen biotransformation has received minimal attention in top predator, marine wildlife, which accumulate high organohalogen levels. The proposed research will expand the understanding and commence with new research on the species-specific role, mechanisms and environmental ecological importance and significance of biotransformation in the fate, bioaccumulation and thyroid hormone transport/inter-conversion, on legacy and emerging, chlorinated and brominated organics in top-predator wildlife sentinels of contaminant and other (e.g., climate change) stresses from the Great Lakes (herring gulls) and the Arctic (polar bears and glaucous gulls).

在环境中持续存在和生物积累的人造化学品越来越多地与野生动物和人类的不利影响联系在一起。在野生动物中发现的许多生物蓄积性“遗留”和“新出现”污染物都含有氯和溴，包括多氯联苯（PCBs）和溴化阻燃剂（BFR）类，即多溴联苯醚（PBDEs）。有机体从体内清除有机卤素和其他外来化学物质的能力依赖于能够调节新陈代谢和生物转化的酶。生物转化（如氧化和脱溴过程）在氯化和溴化有机卤素的命运和生物积累中的作用和意义尚不清楚，其中包括在不同物种和食物网中，特别是在顶级捕食野生动物中形成含羟基（OH-）或“酚”代谢物。正如一些野生动物中多氯联苯和多溴二苯醚所显示的那样，生物转化可导致持久性的多氯联苯和多溴二苯醚代谢物，尽管对这些“二级”污染物的形成、生物积累和毒性动力学仍然知之甚少。oh -多氯联苯、oh -多溴二苯醚、相关酚类化合物/代谢物、多溴二苯醚的脱溴化产物和目前使用的bfr通过激素模拟具有“生物活性”，并可能干扰甲状腺激素依赖的功能和过程（例如激素运输和酶介导的相互转化）。内分泌（甲状腺）活动及其对有机卤素生物转化的影响在积累大量有机卤素的顶级捕食者、海洋野生动物中得到的关注很少。建议的研究将扩大对物种特异性作用、机制和生物转化的环境生态重要性和意义的理解，并开始新的研究，在污染和其他(例如：来自五大湖（鲱鱼鸥）和北极（北极熊和白霜鸥）的压力。