The sediments of Union Lake in Southern New Jersey are contaminated with arsenic released from the Vineland Chemical Company Superfund site 11 km upstream. Seasonal anoxia has been shown to release arsenic from sediments to similar lakes; this process was hypothesized as a major arsenic source to Union Lake. Data indicate, however, that releases of arsenic to bottom waters from the sediments or from pore waters within the sediments are relatively minor: bottom water arsenic concentrations reached ~30 ppb (~12 μM) at most, representing <13% of the dissolved arsenic content of the lake. Manganese concentrations increase more quickly and to higher levels than arsenic and iron concentrations; maximum [Mn]= ~13 ppm (~250 μM), maximum [Fe] = ~6 ppm (~120 μM). Incubation experiments support the hypothesis that manganese acts as a redox buffer and prevents large arsenic releases. Under the observed conditions, little of the arsenic in the water column is from contaminated sediment. This study also suggests that arsenic release from sediment to lake water may be more important in lakes that remain anoxic more continuously.

中文翻译：

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锰氧化还原缓冲限制了新泽西州联合湖受污染沉积物中砷的释放

新泽西州南部联合湖的沉积物被上游 11 公里的 Vineland Chemical Company Superfund 站点释放的砷污染。季节性缺氧已被证明会将沉积物中的砷释放到类似的湖泊中；这个过程被假设为联合湖的主要砷来源。然而，数据表明，沉积物或沉积物中孔隙水向底水释放的砷相对较少：底水砷浓度最多达到 ~30 ppb (~12 μM)，占溶解砷的 <13%湖的内容。与砷和铁的浓度相比，锰的浓度增加得更快，并达到更高的水平；最大值 [Mn]= ~13 ppm (~250 μM)，最大值 [Fe] = ~6 ppm (~120 μM)。孵化实验支持锰作为氧化还原缓冲剂并防止大量砷释放的假设。在观察到的条件下，水体中的砷很少来自受污染的沉积物。这项研究还表明，在持续缺氧的湖泊中，从沉积物释放到湖水中的砷可能更为重要。