Water quality impacts and river system recovery following the 2014 Mount Polley mine tailings dam spill, British Columbia, Canada
Water quality impacts and river system recovery following the 2014 Mount Polley mine tailings dam spill, British Columbia, Canada
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DOI：
10.1016/j.apgeochem.2018.01.012
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发表时间：
2018-04-01
影响因子：
3.4
通讯作者：
Jamieson, Heather E.
中科院分区：
文献类型：
--
作者：
Byrne, Patrick;Hudson-Edwards, Karen A.;Jamieson, Heather E.
2014年8月4日，加拿大不列颠哥伦比亚省波利山尾矿堤坝决口，这是有记录以来第二大的矿山废物泄漏事件。矿山经营者迅速做出反应，从主要接收水道中清除了大量尾矿，稳定了河流走廊，并开始建设一条新的河道。这为研究部分恢复的碱性河流系统中元素循环的空间模式提供了一个独特的机会。总体而言，水质影响被认为是低的，铜是唯一令人担忧的因素，在较小程度上是V。然而，河流铜负荷的空间格局表明，在流域的不同部分，化学(在低流量时占主导地位)和物理(在高流量时占主导地位)活化过程。化学活化是由于河岸尾矿中铜硫化物(黄铜矿)的氧化以及尾矿和河床沉积物中含铜铁氧化物的还原溶解，而物理活化则是由于下游富铜水系沉积物的侵蚀和悬浮。尽管在哈泽尔廷溪水中铜含量升高很明显，但这被认为是对溪流铜浓度自然升高的分水岭的相对较小的扰动。尾矿和接收水道的碱性确保了大多数水铜迅速与溶解的有机物或沉淀形成次生矿物相络合。我们的数据突出表明，迅速清除溢出的尾矿和稳定河流走廊可以限制受影响流域的化学影响，但当溢出的尾矿和接收环境是碱性的时，(铜的)化学动员仍然可以发生。我们提出了一个概念模型的铜循环在哈泽尔廷小溪流域。
The Mount Polley mine tailings embankment breach on August 4th, 2014, in British Columbia, Canada, is the second largest mine waste spill on record. The mine operator responded swiftly by removing significant quantities of tailings from the primary receiving watercourse, stabilizing the river corridor and beginning construction of a new river channel. This presented a unique opportunity to study spatial patterns of element cycling in a partially-restored and alkaline river system. Overall, water quality impacts are considered low with Cu, and to a lesser extent V, being the only elements of concern. However, the spatial pattern of stream Cu loading suggested chemical (dominant at low flow) and physical (dominant at high flow) mobilization processes operating in different parts of the watershed. Chemical mobilization was hypothesized to be due to Cu sulfide (chalcopyrite) oxidation in riparian tailings and reductive dissolution of Cu-bearing Fe oxides in tailings and streambed sediments whereas physical mobilization was due to erosion and suspension of Cu-rich stream sediments further downstream. Although elevated aqueous Cu was evident in Hazeltine Creek, this is considered a relatively minor perturbation to a watershed with naturally elevated stream Cu concentrations. The alkaline nature of the tailings and the receiving watercourse ensures most aqueous Cu is rapidly complexed with dissolved organic matter or precipitates as secondary mineral phases. Our data highlights how swift removal of spilled tailings and river corridor stabilization can limit chemical impacts in affected watersheds but also how chemical mobilization (of Cu) can still occur when the spilled tailings and the receiving environment are alkaline. We present a conceptual model of Cu cycling in the Hazeltine Creek watershed.