Collaborative Research: Tracing Coal Ash Solids in the Environment - Implications for long-term contamination of the aquatic ecosystem

煤燃烧残渣是美国产生的最大的工业固体废物，每年的产生量超过1亿吨。虽然产生的部分火山灰被回收利用，主要用于水泥行业，但超过一半被储存在火山灰蓄水池和垃圾填埋场。由于火山灰含有高浓度的重金属，很容易进入水中，因此将火山灰倾倒在漏水蓄水池中可能会破坏环境和水资源。飓风风暴和大洪水已被证明会导致火山灰泄漏到北卡罗来纳州东部的萨顿湖，并污染湖泊生态系统。这一NSF项目旨在检测整个北卡罗来纳州不同湖泊中沉积物中的火山灰污染，并评估这些湖泊中的火山灰可能对环境造成的影响。该项目将开发新的方法来检测环境中的火山灰。对于生活在灰池和受影响湖泊附近的社区来说，了解主要弃置场以外的火山灰的潜在存在及其对湖泊的生态影响是很重要的。使用科学方法检测环境中的火山灰对于公正和科学地评估火山灰对居住在北卡罗来纳州农村地区的居民的风险是重要的。这项拟议的研究旨在从北卡罗来纳州主要火山灰处置地点附近的湖泊收集沉积物和孔隙水样本，以检测火山灰的存在及其对生态系统的影响。这项研究的基础是开发新的地球化学和物理方法来追踪环境中的火山灰及其污染物，方法是整合海底沉积物中存在的火山灰的独立替代指标，包括痕量金属分布、锶同位素比值(87Sr/86Sr)、铅稳定同位素(206Pb/208Pb、207Pb/206Pb)、放射性核素(228Ra、226Ra、210Pb、137Cs)、磁化率和磁粒度测定。这项侦察研究将调查在极端水文事件期间可能进入北卡罗来纳州火山灰蓄水池附近湖泊的火山灰和污染物的空间和时间分布。这项研究还将通过淋溶实验和测量湖底沉积物中的孔隙水来评估从火山灰固体中动员污染物到生态系统中的情况。该项研究的目的是：(1)开发确定沉积物中的火山灰及湖底沉积物孔隙水中相关污染物的方法；(2)评估未监测到的火山灰在受影响湖泊中的泄漏程度；(3)确定火山灰在受影响湖泊中的停留时间；(4)评估未监测到的火山灰泄漏进入北卡罗来纳州湖泊可能造成的长期生态影响。灰的环境遗产是美国东南部的新兴话题之一。灰池的泄漏和泄漏已经证明对灰场附近的地下水和地表水的质量产生了环境影响。正在运营的燃煤发电厂预计将在未来十年退役，这需要永久性地解决通常储存在湖泊和溪流附近的灰库中的大量灰烬问题。火山灰泄漏到萨顿湖的证据进一步引发了公众对环境和人类健康安全的担忧。这一NSF项目将为与火山灰储存和管理相关的环境风险评估建立科学的标准。杜克大学的研究生和本科生以及阿巴拉契亚州立大学和蒙特克莱尔州立大学的本科生将在该项目中发挥积极作用。该项目的成果将被用于构建一个从火山灰污染到“移动中的水”的模块，这是阿巴拉契亚州地质和环境科学部的一个K-12推广项目。除了在科学期刊上发表和在专业会议上发表外，该项目的成果还将通过以下方式传播给普通公众和居住在火山灰蓄水池和受影响湖泊附近的社区：科学出版后的新闻稿、与当地社区合作的环境非政府组织的沟通、与居民直接对话的风险较大社区的市政厅会议、指定的网站和社交媒体、联邦(美国环保局、国会)和州(NC众议院)机构的交流和结果展示。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Coal combustion residuals (known as coal ash) is the largest industrial solid waste generated in the U.S., with production rates of over 100 million tons per year. While some fraction of the generated coal ash is recycled, mostly for the cement industry, over half is stored in coal ash impoundments and landfills. Since coal ash contains high concentrations of heavy metals that are easily transported into water, the disposal of coal ash in leaky impoundments can damage the environment and water resources. Hurricane storms and large floods have been shown to cause spills of coal ash into Sutton Lake in eastern North Carolina and contamination of the lake ecological system. This NSF project seeks to detect coal ash contamination in sediments within different lakes throughout North Carolina and to evaluate the possible environmental impacts of coal ash in these lakes. The project will develop novel methods to detect coal ash in the environment. Understanding the potential occurrence of coal ash outside the major disposal sites and the ecological impact in the lakes is important for the communities living near coal ash ponds and the impacted lakes. The use of scientific methods to detect coal ash in the environment is important for an unbiased and scientific-base evaluation of the risks of coal ash to residents living in rural areas of North Carolina. The proposed study aims to collect sediments and pore water samples from lakes near major coal ash disposal sites in North Carolina in order to detect the presence of coal ash and its impact on the ecosystem. The study is based on developing novel geochemical and physical methods for tracing coal ash and its contaminants in the environment through integration of independent proxies for the presence of coal ash in the bottom sediments including trace metals distribution, strontium isotope ratios (87Sr/86Sr), lead stable isotopes (206Pb/208Pb, 207Pb/206Pb), radionuclides (228Ra, 226Ra, 210Pb, 137Cs), magnetic susceptibility, and magnetic granulometry. This reconnaissance study will investigate the spatial and temporal distribution of coal ash and contaminants likely introduced during extreme hydrologic events into lakes near coal ash storage impoundments in North Carolina. The study will also evaluate the mobilization of contaminants from coal ash solids into the ecosystem through leaching experiments and measurement of pore water from the lake bottom sediments. The objectives of the study are (1) to develop methods for identification of coal ash in sediments and associated contaminants in pore water extracted from lake bottom sediments; (2) to evaluate the magnitude of unmonitored coal ash spills in the impacted lakes; (3) to determine the residence time of sediments in lakes impacted by coal ash spills; and (4) to evaluate the long-term ecological effects that could result from unmonitored coal ash spills into lakes in North Carolina. The environmental legacy of coal ash is one of the emerging topics in the southeastern U.S. Leaking of coal ash ponds and spills have shown to have environmental effects on the quality of groundwater and surface water near coal ash disposal sites. The expected decommissioning of the operating coal-fired power plants during the next decade requires permanent solutions for the large volumes of coal ash commonly stored in coal ash impoundments near lakes and streams. The evidence of a coal ash spills to Sutton Lake has further raised public concerns about the environmental and human health safety. This NSF project will establish scientific-based criteria for environmental risks assessment associated with coal ash storage and management. Graduate and undergraduate students from Duke University, and undergraduate students from Appalachian State and Montclair State University will take active roles in the project. The results of the project will be used to construct a module on coal ash pollution to “Water on the Move”, a K-12 outreach program in the Department of Geological and Environmental Sciences at Appalachian State. In addition to publication in scientific journals and presentation in professional conferences, the results of this project will be disseminated to the general public and communities living near coal ash impoundments and impacted lakes through press releases following scientific publication, communications with environmental NGOs working with the local communities, townhall meetings with communities at larger risks with direct dialogue with residents, a designated website and social media, communication and presentation of the results in federal (U.S. EPA, Congress) and state (NC House of Representatives) agencies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.