Impacts of climate variation on mercury dynamics in the Mackenzie River and Beaufort Sea

摘要

To investigate the role the Mackenzie Basin plays on elevated concentrations of mercury (Hg) in marine mammals, water, sediment, and permafrost samples were taken from throughout the lower Mackenzie Basin. A total of 64 sites were sampled in the summer of 2003 in the Mackenzie River and its major tributaries. Preliminary data show total dissolved mercury concentrations in the basin ranging from 0.57 to 26.67 ng/L with a median value of 4.24 ng/L. The high values were found in the central reaches of the river between the Wrigley and Ontaritue Rivers, with the highest values on the Mackenzie River near the Mountain River (24.22 ng/L) and in the Ochre River (26.67 ng/L). Levels at several locations in the Mackenzie River estuary averaged about 2.0 ng/L. Levels of mercury in sediments were found to generally range from 0.006 mu g/g and 0.089 mu g/g (dry weight) with the exception of a few high values obtained in the middle reaches of the river.