It has been observed in some aquatic systems, such as lakes and oceans, that when ice forms solutes are excluded from the ice, increasing their concentrations in the water. This process, known as solute ice exclusion, could be important in rivers and streams where ice can be a significant fraction of the total volume, potentially significantly increasing chemical concentrations in the water. There have been no reported observations of solute dynamics during ice formation in rivers and streams, however, even though the freeze–thaw cycle is a common phenomenon for lotic systems in cold regions. To investigate this process, a variety of solutes were measured during three ice formation events in a mine-waste-polluted river in western Montana. A laboratory study was also conducted to determine how different metal cations partition when ice forms. It was found that solute concentrations significantly increase during the early stages of ice formation. Correlations with ion size and changes in temperature support the idea that ice exclusion was controlling solute dynamics during these periods. These observations could have important implications for predicting the environmental impacts of toxic solutes in rivers and streams subject to seasonal ice formation.

中文翻译：

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冰形成过程中河流溶质浓度的观测

在一些水生系统中观察到，例如湖泊和海洋，当冰形成时，溶质被排除在冰之外，增加了它们在水中的浓度。这个过程被称为溶质冰排斥，在河流和溪流中可能很重要，因为冰可能占总体积的很大一部分，可能会显着增加水中的化学物质浓度。然而，尽管冻融循环是寒冷地区水流系统的常见现象，但还没有关于河流和溪流冰形成过程中溶质动力学的观察报告。为了研究这个过程，在蒙大拿州西部一条被矿山废物污染的河流中，在三个冰形成事件中测量了各种溶质。还进行了一项实验室研究，以确定当冰形成时不同的金属阳离子如何分配。发现在冰形成的早期阶段溶质浓度显着增加。与离子大小和温度变化的相关性支持在这些时期冰排除控制溶质动力学的想法。这些观察结果可能对预测受季节性结冰影响的河流和溪流中有毒溶质对环境的影响具有重要意义。