In situ measurements of metal speciation in the Canadian Arctic

环境中的痕量金属可能对水生生物和人类带来益处或风险。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，仅考虑总金属浓度来评估风险/受益已不再足够。相反，有必要确定有毒元素的物理化学形式（即物种形成），因为同一金属的不同形式可以从必需到无害到剧毒。在这个计划中，一个新开发的时间集成被动采样系统监测金属形态，扩散梯度薄膜技术（DGT），将开发和优化北极条件。我们5年的野外工作将分别集中在春季过渡期的淡水/基流和冰下水华期间的丘吉尔河口（马尼托巴的哈德逊湾）和加拿大高北极研究站（CHARS）附近的剑桥湾。溶解有机物质量和自由/不稳定的金属浓度DGT测量之间的联系将进行调查。这项研究计划将使我们能够更好地了解在北极水生系统中的金属形态的时间变化，并有助于在极地科学的HQP形成。

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.