ABSTRACT

Sediments as archives of mercury deposition in the Arctic - how successful are they at reproducing the atmospheric trends?

Prof. Peter Outridge, AU-Herning Research and Education Centre, Aarhus University,
and Geological Survey of Canada, Ottawa, Canada

Lake sediments (and to a lesser extent marine sediments) have been widely employed as natural archives of the deposition of atmospheric mercury. As mercury is a global pollutant with serious environmental and human health implications, and because sediments are the most abundant record we have in northern regions of airborne mercury’s deposition rates and trends, the reliability of sediments as mercury archives is an important issue for environmental geochemistry. 

This talk will compare and contrast the lake sediment records of mercury presently available from Arctic and sub-Arctic regions with other measures of atmospheric mercury levels and trends over recent decades and centuries, such as emission inventories, modeling studies, and other natural archives such as glacial ice, peat bogs, marine sediments and archeological animal remains. The assumptions underlying the use of lake sediments as archives will be reviewed. The impact of climate warming on the processes controlling sediment mercury levels, and the problems that this impact creates in interpreting the sedimentary record, will be highlighted.