Remediation Effectiveness for Mining Sites: Hysteresis and Metal Mixtures Effect

摘要在几乎所有生态系统中，金属都以混合物的形式存在，在矿区尤其如此。准确评估金属接触及其对人类和生态系统的影响，必须考虑到混合效应，这种效应可能是加性的、小于加性的或大于加性的。然而，目前的监管和管理做法通常针对个别金属，因为目前还没有足够的工具来预测混合物的生物利用度和毒性。我们的长期目标是通过提高测量、理解和预测环境污染引起的金属混合物的生物利用度和毒性的能力来解决这一缺点。在这项工作中，我们提出了三个具体项目。首先，我们将解决一个主要的挑战，在分析测量的金属生物利用度的发展“水母”采样器，以获得自由金属浓度的水/沉积物系统。实验将在实验室和中心城市/Clear Creek超级基金现场的采样器现场部署中进行。其次，我们将进一步发展一个模型的毒性金属混合物的水生生物个体物种的基础上的混合金属，多网站的生物配体模型（MMMS BLM）。这将由实验室D完成。使用简单溶液和从现场收集的水样进行magna毒性测试。第三个目标是将前两个目标中获得的程序和信息与在实验室建立的河流微生态系统中金属混合物对接触混合物的水生群落的更复杂影响的测量相结合。我们还将在金属污染的河流中进行“自然实验”，并检查安装处理系统之前、期间和之后的反应，该系统将降低金属的浓度。因为像铁这样的一些金属对水生无脊椎动物和河流中的鱼类有毒，但也会使其他金属的生物利用度降低（即，保护性的），我们期望看到随着处理系统降低Fe负载，在流的恢复中的滞后。最终，在这个项目中，我们希望改进评估方法，这将为保护人类和生态系统健康提供更好的手段。 公共卫生相关性：在我们的社会中，金属的使用产生了大量被矿山废物污染的生态系统的不良后果。必须评估污染物被生物体吸收的程度及其生物利用度，以了解其对人类及其自然环境的潜在危害。在这个项目中，我们改进了评估方法，最终为保护人类和生态系统健康提供更好的手段。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: NARRATIVE Use of metals in our society has the unwanted consequence of creating vast numbers of ecosystems contaminated with mine wastes. The degree to which contaminants can be taken up by an organism, their bioavailability, must be assessed in order to know the potential harm to humans and their natural environment. In this project we make improvements in assessment methods to ultimately provide better means for protecting human and ecosystem health.