Date Published: March 7, 2018
Publisher: Springer Netherlands
Author(s): Rune Dietz, Anders Mosbech, Janne Flora, Igor Eulaers.
Despite the remoteness of the North Water, Northwest Greenland, the local Inughuit population is affected by global anthropogenic pollution and climate change. Using a cross-disciplinary approach combining Mercury (Hg) analysis, catch information, and historical and anthropological perspectives, this article elucidates how the traditional diet is compromised by Hg pollution originating from lower latitudes. In a new approach we here show how the Inughuits in Avanersuaq are subject to high Hg exposure from the hunted traditional food, consisting of mainly marine seabirds and mammals. Violation of the provisional tolerably yearly intake of Hg, on average by a factor of 11 (range 7–15) over the last 20 years as well as the provisional tolerably monthly intake by a factor of 6 (range 2–16), raises health concerns. The surplus of Selenium (Se) in wildlife tissues including narwhals showed Se:Hg molar ratios of 1.5, 2.3, and 16.7 in muscle, liver, and mattak, respectively, likely to provide some protection against the high Hg exposure.
Mercury (Hg) and in particular methyl-Hg biomagnifies and is present throughout the Arctic food chain, leaving high trophic marine avian and mammalian species with high body burdens ( Dietz et al. 1996; AMAP 1998). An estimated 200–300 tons of Hg are transported annually to the Arctic by long-range atmospheric and oceanic processes and ocean currents from various anthropogenic activities at mid-latitudes, emphasizing the worldwide nature of Hg pollution (AMAP 1998, 2011; Berg et al. 2001; Lindberg et al. 2001; Lu et al. 2001). A recent focus on Integrating mercury research and policy in a changing world” has just been issued in a special section on mercury in Ambio addressing the extensive global problems and effects from use, emission, and global transport of Hg across the World (e.g., Chen and Driscoll 2018). Although Hg is a naturally occurring element, worldwide anthropogenic activity has led to a manifold increase of Hg in the Arctic environment compared to pre-industrial times (Dietz et al. 2006, 2009; Braune et al. 2011). Furthermore, Hg emissions are projected to further increase unless new pollution abatement technologies are applied to coal-fired power plants (Streets et al. 2009).
The previous ways of evaluating temporal contaminant trends in Arctic wildlife and Inuit food items have focused on monitoring with regular time intervals a few “essential” species of ecological importance to the hunting communities. In addition, several studies on geographical and temporal contaminant trends have been conducted on the Inuit populations across the Arctic (AMAP 2003, 2009, 2015). However, the present study has, for the first time, estimated seasonal and long-term temporal change of Hg entering an Arctic community, i.e., Avanersuaq, based on a 20-year record of hunting trends as well as evaluation of the Hg content in a large number of important hunted foods. The results of this study detect the main sources of Hg from the hunt, of which the narwhal meat are the most important, and reveals a number of climate related as well as cultural and socio-economic changes affecting the invisible threat of Hg exposure in Inuit populations. This study add evidence to that long-range transport of Hg in even a remote hunting society like the Inughuit in Avanersuaq are heavily affected by anthropogenic processes from the industrialized part of the world. The food chain biomagnification of Hg renders marine top predators, being important food items for the NOW Inuit population, ultimate sinks of Hg amplify the effects of Hg from southern latitudes. However, the marine food has beneficial nutritional aspects as it is also rich in vitamins, micronutrients, fatty acids, and Se, which is particularly true for mattak. In fact, Se is likely an antagonistic mechanism reducing the toxic impact of Hg. Nonetheless, dietary advice in Greenland can reduce the exposure to Hg, and as such, the Greenland Board of Nutrition is tasked with providing balanced information to the public about contaminants in traditional marine food items and general information about a healthy and nutritious diet. Pregnant and nursing women, as well as children and young people are encouraged to continue to eat the traditional marine food but to avoid or reduce consumption of older seals, toothed whales, seabirds, and polar bear, due to high concentrations of contaminants. Supplementary hunt oriented towards more terrestrial animals and increased fishing on lower trophic species has the potential of reducing human exposure to Hg. Similar dietary advice is already given in other (sub)Arctic areas including Canada and the Faroe Islands, where consumption of marine mammals is also traditional. Finally, the Minamata Convention has recently entered into force, partly prompted by the documentation of high Hg concentrations within the Arctic marine ecosystem and hunting societies. It is the hope that it will facilitate a reduction of long-range transport of Hg into the Arctic similar to what has been achieved with the Stockholm Convention on POPs (Minamata Convention 2017; Stockholm Convention 2017).