Cervi Eduardo Cimino, Hudson Michelle, Rentschler Alison, Clark Sean, Brown Steven S, Burton G Allen
School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA.
Environmental Remediation and Restoration, The Dow Chemical Company, Midland, Michigan, USA.
Environ Toxicol Chem. 2022 Jan;41(1):193-200. doi: 10.1002/etc.5258. Epub 2021 Dec 22.
Wilson Mine is a former vanadium mine site located in the Ouachita Mountains near Hot Springs, Arkansas. The site, which drains via two streams to Lake Catherine, has undergone extensive reclamation to significantly reduce groundwater and surface water contact with mine spoils. One of the streams passes through a former mine pit forming East Wilson Pond, and flux from pit lake sediments can result in elevated metal, that is, zinc (Zn), concentrations in overlying water. To mitigate potential risks, an investigation was conducted to evaluate the efficacy of capping materials for partitioning Zn-contaminated sediments from overlying water in East Wilson Pond. A 28-day laboratory study compared the effectiveness of capping materials including combinations of limestone, bentonite clay, and gravel for mitigating Zn flux, including under reasonable worst-case conditions (pH 5.5) encountered in the hypolimnion. Dissolved Zn was monitored over time in overlying water and in sediment porewaters within untreated controls and within the capping layer of treated systems. The use of limestone and/or bentonite clay improved buffering capacity compared to the noncapped control, and pH declined gradually but only modestly in the overlying water and porewater of all treated systems. Concentrations of Zn in overlying water of the noncapped control increased from approximately 30 to 100 µg/L during the study period, while concentrations in the overlying water and porewater of systems containing capping materials remained low (10-30 µg/L). The results demonstrated the effectiveness of the capping materials for neutralizing pH and reducing Zn flux, and a three-layer cap consisting of limestone (top) + bentonite clay (middle) + gravel (bottom) was determined to be most effective. These results were used to inform the selection of materials for the application of a cap to reduce Zn flux from the pit lake sediments. Environ Toxicol Chem 2022;41:193-200. © 2021 SETAC.
威尔逊矿是一个 former 钒矿遗址，位于阿肯色州温泉城附近的沃希托山脉。该遗址通过两条溪流排水至凯瑟琳湖，已经历了广泛的复垦，以显著减少地下水和地表水与矿渣的接触。其中一条溪流穿过一个 former 矿坑，形成了东威尔逊池塘，矿坑湖沉积物的通量可能导致上覆水中金属（即锌（Zn））浓度升高。为了降低潜在风险，进行了一项调查，以评估覆盖材料将东威尔逊池塘中受锌污染的沉积物与上覆水隔开的效果。一项为期28天的实验室研究比较了包括石灰石、膨润土和砾石组合在内的覆盖材料在减轻锌通量方面的有效性，包括在下层滞水层中遇到的合理最坏情况条件（pH 5.5）下。在未处理的对照以及处理系统的覆盖层中的上覆水和沉积物孔隙水中，随时间监测溶解的锌。与未覆盖的对照相比，使用石灰石和/或膨润土提高了缓冲能力，并且在所有处理系统的上覆水和孔隙水中，pH逐渐下降但幅度较小。在研究期间，未覆盖对照的上覆水中锌浓度从约30微克/升增加到100微克/升，而含有覆盖材料的系统的上覆水和孔隙水中的浓度保持较低（10 - 30微克/升）。结果表明覆盖材料在中和pH和减少锌通量方面的有效性，并且确定由石灰石（顶部）+膨润土（中间）+砾石（底部）组成的三层覆盖最有效。这些结果被用于为选择用于覆盖以减少矿坑湖沉积物中锌通量的材料提供依据。《环境毒理学与化学》2022年；41:193 - 200。© 2021 SETAC。 （注：原文中“former”未准确翻译，结合语境，这里推测可能是“废弃的”意思，但按照要求保留了英文。）
