Effects of Flow Regime on Metal Concentrations and the Attainment of Water Quality Standards in a Remediated Stream Reach, Butte, Montana
Effects of Flow Regime on Metal Concentrations and the Attainment of Water Quality Standards in a Remediated Stream Reach, Butte, Montana
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DOI：
10.1021/acs.est.6b03190
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发表时间：
2016-12-06
影响因子：
11.4
通讯作者：
Walton-Day, Katherine
中科院分区：
文献类型：
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作者：
Runkel, Robert L.;Kimball, Briant A.;Walton-Day, Katherine
低流量天气采样活动经常被用作描述受采矿影响流域特征的主要工具。虽然这些活动是场地特征描述的宝贵组成部分，但仅关注低流量条件的调查可能会产生误导性结果。本文的目的是证明这一点，并阐明机制负责在降雨径流金属的释放-这一目标是解决使用的数据从昼夜和天气采样活动进行了为期两天的时间。低流量天气采样结果表明，大多数成分的浓度符合水生标准。这一发现是在对比的结果，从昼夜采样活动，捕获在降雨径流的浓度急剧增加。在过程线上升段的浓度是在天气采样期间观察到的浓度的2-23倍（大多数增加>10倍），在过程线下降段保持升高，以产生顺时针滞后环。负责释放金属的水文机制包括由于河床固体的再悬浮、冲积尾矿的侵蚀和漫流而增加的运输。降雨还提高了冲积地下水位，增加了渗流区的渗透，可能导致事件发生前已干燥的冲积尾矿溶解。
Low-flow synoptic sampling campaigns are often used as the primary tool to characterize watersheds affected by mining. Although such campaigns are an invaluable part of site characterization, investigations which focus solely on low-flow conditions may yield misleading results. The objective of this paper is to demonstrate this point and elucidate the mechanisms responsible for the release of metals during rainfall runoff This objective is addressed using data from diel and synoptic sampling campaigns conducted over a two-day period. Low-flow synoptic sampling results indicate that concentrations of most constituents meet aquatic standards. This finding is in contrast to findings from a diel sampling campaign that captured dramatic increases in concentrations during rainfall runoff. Concentrations during the rising limb of the hydrograph were 2-23 times concentrations observed during synoptic sampling (most increases were >10-fold), remaining elevated during the receding limb of the hydrograph to produce a clockwise hysteresis loop. Hydrologic mechanisms responsible for the release of metals include increased transport due to resuspension of streambed solids, erosion of alluvial tailings, and overland flow. Rainfall also elevated the alluvial groundwater table and increased infiltration through the vadose zone, likely resulting in dissolution from alluvial tailings that were dry prior to the event.