Multiple stressors in watersheds

流域暴露于各种污染物，以及自然和人为的压力，可以相互作用，对鱼类和其他生物体造成不利影响。污染物通常也以复杂的混合物形式进入流域，其组成和性质各不相同，极大地影响其环境归宿、生物利用度和毒性（生态毒理学）。我们目前缺乏对这些相互作用的了解，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种压力源时，造成了相当大的不确定性。当前的研究计划正在努力更好地了解流域中污染物的影响和相互作用，并开发考虑自然变异背景下多种压力源的预测累积效应框架。在我们过去的研究中，已经表明，城市废水含有大量的化学物质，有可能改变鱼类的生理，代谢和内分泌功能。在格兰德河流域，野生彩虹镖鲈（Etheostoma caeruetum）暴露于废水排放引起的变化，在所有层次的生物组织（分子种群）。不幸的是，由于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对鱼类造成不利影响的认识不足，因此无法将环境中的特定污染物与野生鱼类的影响联系起来。该提案的重点是将彩虹镖鲈（卵至成虫）受控暴露于怀疑通过不同机制对鱼类产生影响的特定化学品（乙炔基甜菜碱、三氯生、二甲双胍），并与废水排放物（复杂混合物）进行对比。 它将测试这些化学物质单独和混合的能力，以引起（可能增强）生理和生殖方面的各种关键变化，包括基因表达，性腺发育（包括雌雄同体），性类固醇生产和行为。我们将补充这项研究的命运和影响模型的发展，利用十年的化学品暴露和影响的数据，在格兰德河的鱼类，以及对最近的污水质量变化的反应。最后，我们将开始研究新的功能化纳米粒子（纳米药物）的新兴威胁的环境风险，预计在不久的将来也将被释放到废水系统中。 因此，这项研究将继续推进我们对目前限制国家和国际机构评估和管理这种多样性污染物释放到我们流域的不确定性和风险的能力的重要机制和过程的理解。

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.