Relative importance of organic- and iron-based colloids in six Nova Scotian lakes
Relative importance of organic- and iron-based colloids in six Nova Scotian lakes
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DOI：
10.1038/s41545-021-00115-4
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发表时间：
2021-04-09
期刊：
影响因子：
11.4
通讯作者：
Gagnon, Graham A.
中科院分区：
文献类型：
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作者：
Anderson, Lindsay E.;Trueman, Benjamin F.;Gagnon, Graham A.
几十年来，北方部分地区的溶解有机物（DOM）浓度一直在增加。这一过程-褐变-通常伴随着铁和铝的增加，但这些并发趋势意味着金属-DOM相互作用的描述很少。在这里，我们使用场流分馏与UV和ICP-MS检测，以测量胶体铁，铝，锰，铜，铀和发色团DOM在六湖超过六个月的大小分布。在过去的三十年中，这些湖泊中有五个在一定程度上褐变，有机碳和颜色的线性增加范围为0.01至0.13 mg C L-1年（-1）和0.13-1.94 PtCo年（-1）。布朗宁趋势更加明显，胶体更丰富的湖泊湿地在其集水区。铁和铝存在于两个主要部分中，标称尺寸为1和1000 kDa。1 kDa级分包括主要DOM信号，而1000 kDa级分在254 nm处吸收最小，可能代表富铁（羟基）氧化物。胶体锰的大小为1000+ kDa，而胶体铜和铀主要发生在1 kDa。这些关联符合该地区湖泊DOC、铁、铝和颜色增加的模式。它们对饮用水处理系统，特别是偏远社区的饮用水处理系统构成重大挑战。鉴于布朗宁趋势预计将继续下去，监测计划将更好地为处理过程的设计和操作提供信息，描述DOM和富铁，主要是无机胶体，有助于不利的水质结果。
Dissolved organic matter (DOM) concentrations have been increasing in parts of the northern hemisphere for several decades. This process-brownification-often accompanies increasing iron and aluminum, but the metal-DOM interactions these concurrent trends imply are poorly described. Here we used field-flow fractionation with UV and ICP-MS detection to measure the size distribution of colloidal iron, aluminum, manganese, copper, uranium, and chromophoric DOM in six lakes over six months. Five of these lakes have browned to some degree in the past three decades, with linear increases in organic carbon and color ranging from 0.01 to 0.13 mg C L-1 yr(-1) and 0.13-1.94 PtCo yr(-1). Browning trends were more pronounced and colloids more abundant in lakes with wetlands in their catchments. Iron and aluminum were present in two primary fractions, sized nominally at 1 and 1000 kDa. The 1 kDa fraction included the primary DOM signal, while the 1000 kDa fraction absorbed minimally at 254 nm and likely represents iron-rich (oxyhydr)oxides. Colloidal manganese was sized at 1000+ kDa, whereas colloidal copper and uranium occurred primarily at 1 kDa. These associations fit with a pattern of increasing DOC, iron, aluminum, and color in the region's lakes. They represent a significant challenge for drinking water treatment systems, especially those in remote communities. Given that browning trends are expected to continue, monitoring plans would better inform treatment process design and operation by characterizing DOM and iron-rich, primarily inorganic colloids that contribute to adverse water quality outcomes.