Mercury (Hg) is a toxic heavy metal that accumulates in aquatic ecosystems, and poses a threat to wildlife and humans across the Arctic. This project aims to identify the terrestrial sources of Hg that enters the Arctic Ocean by river discharge. These sources include anthropogenic Hg, but also geogenic Hg stored in rocks, soils and permafrost. To discriminate between different sources, we will sample and analyze water from different parts of the Mackenzie River Basin in Canada and analyze isotopic composition of both carbon and Hg. We will use results to apportion the sources of riverine Hg, and help assess its fate during transport towards the Arctic Ocean. The data will also be used to model how changes in anthropogenic Hg emission/deposition, permafrost thaw or land use will affect Hg release in Arctic aquatic environments. Outcomes of this project are important for monitoring the efficacy of international measures and agreements on Hg pollution control.
This project is a collaboration between researchers from Uppsala University (PI – Christian Zdanowicz), SLU (Staffan Åkerblom; Karin Eklöf) and ACES, Stockholm University.