Multiple stressors in watersheds

流域暴露于各种污染物，以及可相互作用对鱼类和其他生物造成不利影响的自然和人为应激源。污染物通常还以复杂混合物的形式进入流域，其组成和性质不同，对其环境命运、生物利用度和毒性(生态毒理学)有很大影响。我们目前对这些相互作用缺乏了解，在评估各种人类活动的环境风险时，特别是在考虑跨流域的多个应激源时，造成了相当大的不确定性。目前的研究计划正致力于更好地了解流域中的污染物影响和相互作用，并开发在自然变异性背景下考虑多个应激源的预测性累积影响框架。我们过去的研究表明，城市污水中含有多种化学物质，可能会改变鱼类的生理、新陈代谢和内分泌功能。在大河流域，野生彩虹鱼(Etheostoma Caeruleum)暴露在废水排放中，引起了各级生物组织(分子与种群)的变化。不幸的是，环境中的特定污染物与野生鱼类的影响之间的联系受到了阻碍，因为我们对这些不同的化学物质在早期发育过程中如何相互作用导致鱼类的不良后果缺乏了解。这项建议的重点是通过不同的机制(乙炔雌二醇、三氯生、二甲双胍)将彩虹鱼(卵对成鱼)的受控实验室暴露应用于可能对鱼类造成影响的特定化学品，并与废水(复杂混合物)进行对比。它将测试这些化学物质单独和作为混合物导致(可能增强)生理和生殖方面的各种关键变化的能力，包括基因表达、性腺发育(包括中间性)、性类固醇产生和行为。我们将利用大河鱼类十年的化学暴露和影响数据，以及对最近污水质量变化的反应，开发一个命运和影响模型，以补充这项研究。最后，我们将启动对新型功能化纳米颗粒(纳米药物)新威胁的环境风险的研究，这些纳米颗粒预计也将在不久的将来释放到废水系统中。因此，这项研究将继续促进我们对目前限制国家和国际机构评估和管理向我们的流域排放的这种多样性污染物的不确定性和风险的能力的重要机制和进程的了解。

Watersheds are exposed to a variety of contaminants, as well as both natural and anthropogenic stressors that can interact to cause adverse effects in fish and other organisms. Contaminants also normally enter watersheds as complex mixtures, with differing composition and properties that greatly influence their environmental fate, bioavailability and toxicity (ecotoxicology). Our current lack of understanding of these interactions creates considerable uncertainty when assessing environmental risk of various human activities, especially when multiple stressors are considered across watersheds. The current research program is working toward a better understanding of contaminant effects and interactions in watersheds, and the development of predictive cumulative effects frameworks that consider multiple stressors in the context of natural variability. In our past studies it has been shown that municipal wastewaters contain a large variety of chemicals that have the potential to alter physiology, metabolism and endocrine function in fish. In the Grand River watershed, wild rainbow darter (Etheostoma caeruleum) exposed to wastewater discharges caused changes across all levels of biological organization (molecular to populations). Unfortunately making linkages between specific contaminants in the environment and effects in wild fish is hampered by our poor understanding of how these diverse chemicals interact during early development to cause adverse outcomes in fish. This proposal is focused on applying controlled lab exposures of rainbow darter (eggs to adult) to specific chemicals suspected of causing effects in fish though different mechanisms (ethynylestradiol, triclosan, metformin) and contrasted to wastewater effluents (complex mixture). It will test the ability of these chemicals individually and as a mixture to cause (possibly potentiate) a variety of key changes in physiology and reproduction, including gene expression, gonad development (including intersex), sex steroid production, and behaviour. We will compliment this research with the development of a fate and effects model utilizing a decade of chemical exposure and effects data on fish in the Grand River, and the responses to recent changes in effluent quality. Finally we will initiate studies of the environmental risk of the emerging threat of novel functionalized nanoparticles (nanomedicines) that are also expected to be released into wastewater systems in the near future. The research will therefore continue to advance our understanding of important mechanisms and processes currently limiting the ability of national and international agencies to assess and manage the uncertainty and risk of this diversity of contaminants being released into our watersheds.