Remediation Effectiveness for Mining Sites: Hysteresis and Metal Mixtures Effect

总结 在几乎所有的生态系统中，金属都以混合物的形式存在，在矿区尤其如此。 必须准确评估金属暴露及其对人类和生态系统的影响， 考虑混合效应，它可以是加性的，小于加性的，或大于 添加剂然而，目前的监管和管理做法通常涉及 个别金属，因为还没有足够的工具来预测 混合物的生物利用度和毒性。我们的长期目标是解决这个问题 通过提高测量，理解和预测生物利用度的能力来克服缺点 以及由环境污染引起的金属混合物的毒性。我们有 在这项工作中提出了三个具体项目。首先，我们将解决一个重大挑战， 通过开发“水母”取样器， 获得水/沉积物系统中的游离金属浓度。实验将 在实验室和在中央采样器的现场部署中进行了 城市/清溪超级基金网站。其次，我们将进一步发展一个 金属混合物对个别水生生物物种的毒性， 金属多位点生物配体模型（MMMS BLM）。这将通过 实验室D使用简单溶液和水样的magna毒性试验 从网站上收集的。第三个目标是整合程序， 从前两个目标获得的信息， 金属混合物对河流中暴露于混合物的水生群落的影响 在实验室里建立的微观世界。我们还将进行一项“自然实验”， 金属污染的河流，并检查安装前，安装期间和安装后的反应 一个能降低金属浓度的处理系统。因为有些 铁等金属对水生无脊椎动物和溪流中的鱼类有毒， 其它生物利用度较低的金属（即，保护性），我们预计会看到 由于Fe负载量被处理系统降低，因此物流的回收率降低。最终，在 本项目我们希望改进评估方法，这将提供 更好地保护人类和生态系统的健康。

SUMMARY In almost all ecosystems, metals occur in mixtures, this is especially true at mining sites. Accurate assessment of metal exposure and effects to humans and ecosystems must account for mixture effects, which could be additive, less than additive, or more than additive. However, current regulatory and management practices usually address individual metals, because adequate tools are not yet available for predicting bioavailability and toxicity of mixtures. Our long-term objective is to address this shortcoming by improving the ability to measure, understand, and predict bioavailability and toxicity of metal mixtures arising from environmental contamination. We have proposed three specific projects in this work. First, we will solve a major challenge in analytical measurement of metal bioavailability by developing the "gellyfish" sampler to obtain free metal concentrations in water/sediment systems. Experiments will be performed both in the laboratory and in field deployments of the sampler at the Central City/Clear Creek Superfund site. Secondly, we will further develop a model of the toxicity of metal mixtures to individual species of aquatic organisms based on a mixed- metal, multi-site biotic ligand model (MMMS BLM). This will be accomplished with laboratory D. magna toxicity tests using both simple solutions and water samples collected from the site. The third objective is to integrate the procedures and information gained from the first two objectives with measurements of more complex effects of metal mixtures on aquatic communities exposed to mixtures in stream microcosms set up in the laboratory. We will also conduct a "natural experiment" in a metal-contaminated stream and examine responses before, during and after installation of a treatment system that will decrease concentrations of the metals. Because some metals like Fe can be toxic to aquatic invertebrates and fish in streams but can also make other metals less bioavailable (i.e., be protective), we expect to see a hysteresis in the recovery of the stream as Fe loading is decreased by the treatment system. Ultimately, in this project we expect to make improvements in assessment methods, which will provide a better means for protecting human and ecosystem health.