In situ measurements of metal speciation in the Canadian Arctic

环境中的微量金属可能给水生生物和人类带来益处或风险。它们可以自然产生，也可以部分或全部由人为污染造成。然而，仅考虑总金属浓度来评估风险/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。在这个项目中，一个新开发的用于监测金属形态的时间积分被动采样系统，薄膜扩散梯度技术（DGT），将针对北极条件进行开发和优化。我们为期5年的野外工作将分别集中在春季淡水/基流过渡期和冰华期的丘吉尔河口（哈德逊湾，马尼托巴）和剑桥湾附近的加拿大高纬度北极研究站（CHARS）。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。该研究项目将使我们更好地了解北极水生系统中金属物种形成的时间变化，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.