45 Year Study Reports Consistent Levels of Mercury in Arctic Seals
An Environmental Toxicology and Chemistry study has recently reported steady concentrations of mercury in Canadian Arctic ringed seals. The purposes of the study were to investigate the trends of mercury and selenium in seals from different regions of the Canadian Arctic and to study the possible relationship between age, diet, and climate variables such as air temperature, precipitation, climatic indices, and ice‐coverage and mercury levels. Seals were gathered by hunters in the Beaufort Sea, Central Arctic, Eastern Baffin Island, Hudson Bay, and Ungava/Nunatsiavut regions between 1972 and 2017. Mercury levels showed a very limited decline.
Mercury levels in marine life have been a growing concern for scientists due to bioaccumulation and the toxicity of its methylated species. Marine animals in the arctic, such as ringed seals are an important component of the Arctic indigenous peoples’ diet. The high levels of mercury in these animals can cause health issues and some have already been reported in children, pregnant women, and women of childbearing age who have consumed ringed-seal liver and beluga whale meat.
Scientists have concluded that climate factors are influencing mercury concentrations in seals. Changes in the climate can influence environmental factors, such as air and water temperatures, water chemistry, snow and rain precipitation rates, and sea‐ice coverage and thickness. This can lead to adjustments in food web structures and dynamics. As a result of these adjustments, the storage, transformation, transport, and accumulation of contaminants in organisms can be altered. Faster biogeochemical and ecological changes have been reported in the Arctic, largely due to climate changes. Warmer temperatures and the loss of sea‐ice allow for an increase in direct absorption of gas‐phase contaminants into surface waters, where they make their way into the marine food chain. Longer ice‐free seasons impact the bioenergetics of primary consumers and fish by causing changes in the mercury transformation process and influencing distribution and transport. This increases the consumption of mercury by arctic creatures.
Magali Houde, Ph.D., of Environment and Climate Change Canada, says that “ringed seal is an important species for contaminants surveillance and monitoring across the Arctic. With the collaboration and support of Inuit communities, we’ve been able to study contaminants in seals for decades in Canada”. Scientists will continue to monitor the impacts climate changes have on environmental factors and how those changes influence contaminants in ringed seals.
Houde, Magali, et al. “Mercury in Ringed Seals (Pusa Hispida) from the Canadian Arctic in Relation to Time and Climate Parameters.” Environmental Toxicology and Chemistry, 6 Oct. 2020, setac.onlinelibrary.wiley.com/doi/10.1002/etc.4865.