Arsenic (As) and antimony (Sb) speciation and mobility in river systems can be influenced by the redox conditions of benthic and hyporheic zone sediments. However, our understanding of how temperature fluctuations influence riverine As and Sb mobility over diel and seasonal time frames, via moderation of sediment redox conditions, is poorly constrained. Here we compare diel and seasonal water quality data from a river system contaminated with As and Sb with results from sediment‐water incubations conducted at temperatures spanning 8°C to 32°C under low‐dissolved oxygen conditions. Higher incubation temperatures caused faster microbial respiration, lower redox potential, and greater As_aq concentrations, coincident with reduction of As(V), Mn (III/IV), Fe (III), and SO₄²⁻. Initial rates of As³⁺_aq formation increased exponentially with temperature (Q₁₀ = 3.3 ± 0.5) and were positively correlated with microbial respiration (r² = 0.99, P < 0.01). In contrast, Sb_aq displayed an initially negative and comparatively weak overall temperature dependence during incubations. In river waters, diel mobilization of reduced species (As³⁺_aq and Fe²⁺_aq) and contrasting attenuation of Sb was coincident with lower redox potential during nightly respiration cycles. Distinct seasonal oscillations in river water As_aq were exponentially correlated with temperature (r² = 0.68, P < 0.01), whereas Sb_aq was not. These characteristics reflect the fundamental role of anaerobic metabolism (as influenced by temperature) within benthic and hyporheic zone sediments as a key driver of contrasting riverine As and Sb mobility. The findings imply that riverine As mobility may be enhanced, while Sb mobility possibly attenuated, by eutrophication or by elevated stream temperatures due to a warming climate.

中文翻译：

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季节性温度波动驱动受采矿影响的河流系统中砷和锑的反动。

底栖和流变带沉积物的氧化还原条件会影响河流系统中砷（As）和锑（Sb）的形态和流动性。但是，我们对温度波动如何通过调节沉积物氧化还原条件，在迪尔和季节性时间框架内影响河流砷和锑迁移率的理解受到限制。在这里，我们将被砷和锑污染的河流系统的diel和季节性水质数据与在8°C至32°C的温度下在低溶解氧条件下进行的沉积物-水温育的结果进行比较。较高的培养温度导致更快的微生物呼吸，较低的氧化还原电势和较高的As_水溶液浓度，同时降低了As（V），Mn（III / IV），Fe（III）和SO ₄ ^2-。As ³⁺ _aq形成的初始速率随温度呈指数增长（Q ₁₀  = 3.3±0.5），并且与微生物呼吸呈正相关（r ²  = 0.99，P  <0.01）。相反，Sb _aq在孵育过程中显示出最初的负温度和相对较弱的总体温度依赖性。在河水中，夜间呼吸周期中还原物种（As ³⁺ _aq和Fe ²⁺ _aq）的diel动员以及Sb的对比衰减与较低的氧化还原电位相吻合。在河水明显的季节波动作为_水性与温度呈指数关系（r ²  = 0.68，P  <0.01），而Sb _aq与温度无关。这些特征反映了底栖和流变区沉积物中厌氧代谢（受温度影响）的基本作用，这是对比河流中砷和锑迁移率的关键驱动力。研究结果表明，由于富营养化或由于气候变暖所引起的河流温度升高，河流的砷迁移率可能会增加，而锑的迁移率可能会下降。