Emerging organohalogen contaminants in a bioindicator bird from the St. Lawrence River basin: dietary sources, toxicokinetics and endocrine and bioenergetics effects.

水禽在其生态系统中不断暴露于遗留（多氯联苯、滴滴涕等）和最近引入的（新出现的）有机卤化污染物（ohc）。新兴的OHCs可能包括达到消防安全标准的产品添加剂（溴化阻燃剂- bfrs）和表面活性剂（多氟烷基物质- pfass）。其中一些有机碳目前在消费品中生产和使用，并被释放到水生环境中。目前缺乏关于加拿大野生动物，特别是生活在污染最严重地区的水生物种中这些新出现的有机碳的环境来源、生物转化能力和生物影响的知识。拟议的研究将利用在蒙特利尔岛附近圣劳伦斯河流域高度污染地区繁殖的一种广泛存在的水鸟（环嘴鸥）来解决这些问题。本建议的主要目标是：1)利用新型卫星跟踪系统确定新生羟基碳化物（PFASs和BFRs）对海鸥的日粮来源；2)通过测定海鸥肝脏代谢酶的催化活性、含量和降解能力，探讨新生羟基碳化物在体外系统中的生物转化机制；3)研究这些鸟类新出现的OHCs的组织/血液浓度是否与它们的日常能量消耗和参与代谢功能的激素（甲状腺激素和皮质酮）的血液水平的变化有关。这项工作的新颖性和预期意义在于，它首次结合了一种新的卫星技术来跟踪鸟类的运动、内分泌参数、每日能量消耗的测量和生态毒理学数据。拟议研究的预期结果将为加拿大环境中新出现的化学应激源的动力学和毒理学效应提供新的知识。这项研究还将为加拿大正在进行和未来的化学品风险评估和生态系统健康生物监测提供关键信息。

Aquatic birds are continuously exposed in their ecosystem to legacy (PCB, DDT, etc.) and to more recently introduced (emerging) organohalogenated contaminants (OHCs). Emerging OHCs may include product additives to achieve fire safety standards (brominated flame retardants-BFRs) and surface-active agents (polyfluorinated alkyl substances-PFASs). Some of these OHCs are currently produced and used in consumer products, and are released into the aquatic environment. There is at present a dearth of knowledge on the environmental sources, biotransformation capacity and biological effects of these emerging OHCs in Canadian wildlife, particularly in aquatic species that live in the most severely polluted areas. The proposed research will address these issues using a widespread aquatic bird (ring-billed gull) breeding in a highly polluted area in the St. Lawrence River basin near the Montreal Island. The main objectives of the present proposal are: 1) to determine the dietary sources of emerging OHCs (PFASs and BFRs) to the gulls using a new satellite-based tracking system, 2) to investigate the mechanisms of biotransformation of emerging OHCs in an in vitro system by measuring the catalytic activity, content and degradation capacity of metabolizing enzymes in gull liver, and 3) to study whether the tissue/blood concentrations of emerging OHCs in these birds are associated with changes in their daily energy expenditure and blood levels of hormones that are involved in metabolic functions (thyroid hormones and corticosterone). The novelty and expected significance of this work is that it combines for the first time a new satellite technology to track bird movements, endocrine parameters, a measure of daily energy expenditure and ecotoxicological data. The results anticipated from the proposed research will provide new knowledge on the dynamics and toxicological effects of emerging chemical stressors in the Canadian environment. This research will also generate critical information for ongoing and future chemical risk assessments and ecosystem health biosurveillance in Canada.