In situ measurements of metal speciation in the Canadian Arctic

环境中的痕量金属可能会给水生生物和人类带来好处或风险。它们可能是自然产生的，也可能部分或全部是人为污染造成的。然而，仅考虑金属总浓度来评估风险/收益已不再足够。相反，有必要确定有毒元素的物理化学形态(即形态)，因为同一金属的不同形态可能从必需的、无害的到剧毒的。在这项计划中，将开发一种新开发的用于监测金属形态的时间集成被动采样系统，即薄膜扩散梯度技术(DGT)，并将针对北极条件进行优化。我们为期5年的野外工作将集中在丘吉尔河口(马尼托巴省哈德逊湾)和加拿大北极高地考察站(CHARS)附近的剑桥湾，分别在过渡春季淡水/基流和冰花时期。将研究溶解有机物质量与DGT测量的游离/不稳定金属浓度之间的联系。这项研究计划将使我们能够更好地了解北极水系中金属形态的时间变化，并为极地科学中HQP的形成做出贡献。

Trace metals in the environment may provide benefits or risks to aquatic life and humans. They can arise naturally, or result partly or wholly from man-made pollution. However it is no longer adequate to consider only the total metal concentration to assess risk/benefit. Rather, it is necessary to determine the physicochemical forms of toxic elements (i.e. speciation) because different forms of the same metal can range from essential to innocuous to strongly toxic. In this program, a newly developed time-integrated passive sampling system for monitoring metal speciation, the diffusive gradients in thin films technique (DGT), will be developed and optimized for the arctic conditions. Our 5-year field work effort will focus on the Churchill estuary (Hudson Bay, Manitoba) and in Cambridge Bay near the Canadian High Arctic Research Station (CHARS) during the transition spring freshet/base flow and under ice bloom period respectively. The linkages between dissolved organic matter quality and free/labile metal concentration measured by DGT will be investigated. This research program will allow us to better understand the temporal variations in metal speciation in arctic aquatic systems and contribute in HQP formation in polar sciences.