Development of subcellular distribution methods to identify indirect or direct effects of metals on aquatic organisms

在加拿大，严格的法规控制着采矿和冶炼作业排放到水环境中的污染物的组成。矿业公司目前被要求进行环境影响监测，包括在水环境中进行生物研究，以评估和监测其废水可能造成的影响。斯坦泰克咨询有限公司从事《金属采矿废水法规》(MMER)所要求的EEM研究。它对矿山废水下游和不受废水影响的参照区的各种客户采矿场地进行的调查表明，接收环境中的水生群落往往不同于参照点的水生群落。我们拟议的研究旨在提供一种工具，以确定所观察到的影响实际上是由于水中/饮食中的金属暴露，还是更确切地说，是由于栖息地的差异。 科学文献中的报告表明，暴露于环境中的金属可能会导致金属在鱼类和其他水生物种中积累和毒性。一旦金属进入生物体，它们就会渗透到细胞中，并造成有害影响。或者，进入的金属可以通过与旨在隔离它们并防止它们发挥毒性作用的分子结合来解毒。该项目的第一个目标是以比目前可用的更好的分辨率调查细胞内金属与哪些配体结合，并将金属在特定组份中的积累与毒性联系起来。有了这些信息，第二个目标是开发一种以亚细胞金属分配技术为基础的环境影响监测工具，该工具将比目前使用鱼类和其他水生生物组织金属总积累量的方法更好地估计毒性风险。最后，该项目还将调查金属通过水生食物网的营养转移。这项研究将有助于加深我们对金属对水生生物的毒性作用模式的理解。它还将提高我们监测金属采矿废水对水生生物的风险的能力。

In Canada, strict regulations control the composition of discharges from mining and smelting operations into aquatic environments. Mining companies are currently required to conduct environmental effects monitoring (EEM), which involves conducting biological studies in the aquatic environment to assess and monitor effects potentially caused by their effluent. Stantec Consulting Ltd. is engaged in the EEM studies required as part of the Metal Mining Effluent Regulations (MMER). Its investigations on various client mining sites, conducted downstream from the mine effluent and in reference areas unaffected by the effluent, have revealed that the aquatic communities in the receiving environment often differ from the communities present at the reference sites. Our proposed study is designed to provide a tool to determine if the observed effects are in fact due to waterborne/diet-borne metal exposure or rather to habitat differences. Reports in the scientific literature have demonstrated that exposure to metals in the environment may lead to metal accumulation and toxicity in fish and other aquatic species. Once metals enter living organisms, they can penetrate into their cells and cause deleterious effects. Alternately, the entering metals can be detoxified by binding to molecules designed to sequester them and prevent them from exerting their toxic effects. The first objective of this project is to investigate, with a better resolution than is currently available, to which intracellular ligands metals bind and to relate metal accumulation in specific fractions to toxicity. With this information in hand, the second objective is to develop a tool for environmental effects monitoring based on the subcellular metal partitioning technique that would provide a better estimate of risk of toxicity than the current approach of using total tissue metal accumulation in fish and other aquatic organisms. Finally, the project will also investigate the trophic transfer of metals through the aquatic food web. This research will contribute to advancing our understanding of the toxic modes of action of metals to aquatic organisms. It will also improve our capacity to monitor the risk for aquatic organisms of metal mining effluents.