RAPID: Collaborative Research: Using geochemical signatures to evaluate the impact of a recent coal ash spill on trace elements in water and sediments of the Dan River

1440099/1440067德里/施莱伯2014年2月2日，美国第三大火山灰泄漏事件发生在北卡罗来纳州伊甸市，杜克能源丹河蒸汽厂27英亩废水池下的排水管道坍塌，将火山灰和数百万加仑受污染的水排放到丹河。丹河发源于弗吉尼亚州，流入北卡罗来纳州，然后向北流入弗吉尼亚州，八次越过州界。它最终流入罗阿诺克河，然后进入科尔湖，然后是加斯顿湖，最终进入北卡罗来纳州的阿尔贝马尔湾。这些水域是一个使用率很高的娱乐系统，也是从弗吉尼亚州丹维尔到遥远的弗吉尼亚海滩的城市的饮用水来源。火山灰的有毒成分包括各种污染物，包括砷(As)、铅(Pb)、汞(Hg)和硒(Se)等金属以及一系列有机化合物。虽然蓄水中的元素浓度可以超过饮用水标准和水生生物水质标准，但在丹河新的生物地球化学环境中，与灰烬结合的痕量元素的去向却鲜为人知。溶解和形态的变化会增加金属的毒性，从而威胁到野生动物和未来几年的水的可用性。要回答其中一些问题，多学科方法是必要的。拟议的工作将为环境机构和水资源管理者提供更清楚的图景，了解该河流系统中燃煤残渣衍生污染物的范围、运输时间尺度和清除过程。该项目将提供独特的洞察，了解该流域燃煤残渣衍生污染物在较长时间和空间尺度上的演变，以及可能被认为低于直接补救目标但对水生生态系统的整体生物地球化学功能和健康仍然重要的水平。开发和应用新型和独立的燃煤残渣输入地球化学示踪剂，将有助于消除与污染物浓度数据相关的一些模棱两可的问题，并确定即使在没有污染物作用水平的情况下燃煤残渣输入的程度。虽然州/联邦机构和其他组织最初的重点一直是确定煤炭燃烧残渣池塘流出和河流中的污染物水平，但有几种技术可以让科学家在与煤炭燃烧残渣向科尔水库的运输保持一致的时间和长度尺度上追踪系统的响应。这项拟议的研究将提供工具，追踪后泄漏时期丹河水和沉积物中主要、次要和痕量元素以及稳定同位素S-34(硫-34)的浓度。由于锗(Ge)在煤中富集，应作为一种保守的示踪剂，我们预计Ge将出现异常，Ge/Si(硅)比将成为煤燃烧残渣输入的唯一指纹。认为As/Ge、(铬)、Cr/Ge等微量元素/Ge比值是识别这些元素中与煤燃烧残渣有关的异常的有力工具。S-34在溶解硫酸盐中的稳定同位素分析将作为燃煤残渣输入的第二个约束，可以与Ge/Si和微量元素/Ge比值进行比较。这笔快速资金是为了提供资金，以继续在漏油事件发生后立即开始的采样和分析计划。河流水文过程和生物地球化学过程预计都将显著改变和减轻污染事件的直接影响。为了评估运输和生物地球化学清除对受关注污染物的影响，建立和继续定期采样计划至关重要。

1440099/1440067Derry/SchreiberOn February 2, 2014, the third-largest coal ash spill in the Nation occurred at Eden, North Carolina where a drainage pipe under a 27-acre Duke Energy Dan River Steam Plant waste pond collapsed, discharging coal ash and millions of gallons of contaminated water into the Dan River. The Dan River originates in Virginia and flows into North Carolina and then flows north back into Virginia crossing the state lines eight times. It eventually flows into the Roanoke River, and into Lake Kerr then Lake Gaston and eventually into the Albemarle Sound, NC. The waters serve as a highly used recreation system and as a source of drinking water for cities from Danville, VA to as far away as Virginia Beach. The toxic constituents of coal ash include various contaminants from metals such as arsenic (As), lead (Pb), mercury (Hg) to selenium (Se) along with a suite of organic compounds. While the element concentrations in impoundment water can exceed drinking water criteria and aquatic life water quality criteria, less is known about the fate of trace elements bound to ash in the new biogeochemical environment of the Dan River. Dissolution and changes in speciation can increase metal toxicity thus threaten wild life and water usability for years to come. To answer some of these questions a multidisciplinary approach is necessary. The proposed work should provide a clearer picture to environmental agencies and water managers of the extent, transport time scales, and removal processes of coal combustion residue-derived pollutants in this river system.This project will provide unique insight into the evolution of coal combustion residue-derived contaminants in the basin over longer time and spatial scales, and at levels that may be considered below immediate remediation targets but are still important for the overall biogeochemical function and health of the aquatic ecosystem. The development and application of novel and independent geochemical tracers for coal combustion residue input will help remove some of the ambiguity associated with data on contaminant concentrations, and identify the extent of coal combustion residue inputs even in the absence of action levels of contaminants. While the initial focus by the state/federal agencies and other organizations has been on identifying the levels of contaminants in the coal combustion residue pond outflow and the river, there are several techniques which allow scientists to trace the response of the system in time and length scales consistent with the transport of coal combustion residue to the Kerr Reservoir. This proposed research will provide tools to track the concentrations of major, minor and trace elements as well as the stable isotope S-34 (sulfur-34) in water and sediments in the Dan River in the post-spill period. Because germanium (Ge) is enriched in coals and should act as a conservative tracer, we expect Ge to be anomalous and Ge/Si (silicon) ratios to be a unique fingerprint for coal combustion residue input. It is thought that the As/Ge; (chromium) Cr/Ge and other trace element/Ge ratios should be a powerful tools for identifying coal combustion residue-related anomalies in those elements. The stable isotopic analysis of S-34 in dissolved sulfate will act as a second constraint on the coal combustion residue input that can be compared to the Ge/Si and trace element/Ge ratios. This RAPID funding is to provide funds to continue a sampling and analysis program begun in the immediate aftermath of the spill. Both river hydrologic process and biogeochemical processes are expected to significantly modify and attenuate the immediate impacts of the contamination event. It is vital to establish and continue a regular sampling program in order to assess the impact of transport and biogeochemical removal on contaminants of concern.