Mercury and marine birds in Arctic Canada: effects, current trends, and why we should be paying closer attention

Mercury (Hg) is a naturally occurring trace element that is also a by-product of anthropogenic activities and, in its methylated form, it is a neurotoxin that can have adverse effects on wildlife. The toxicity of Hg for humans, wildlife, and ecosystem health merits monitoring of its concentrations by various sampling means. Marine birds are widely used as indicators of ecosystem health, including biomonitoring of Hg in the Arctic. Since the mid-1970s, Hg concentrations in marine birds have been monitored across the Canadian North. Current Hg burdens in most northern marine bird species are below levels associated with health concerns, but several species have concentrations that are at or near levels associated with impaired reproduction. Arctic marine birds in Canada may be particularly at risk from increasing Hg levels associated with changing climatic conditions and long-term Hg deposition patterns. Research on marine birds should, therefore, continue to focus on spatial and temporal patterns of Hg contamination, assessing levels and biological effects in species that are experiencing high concentrations, and among species that are widely harvested due to the possible implications for human health.