Environmental scientists have known that high levels of the toxic element, mercury, have been accumulating in the Arctic Ocean for some time.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/high-concentrations-toxic-mercury-arctic-circumpolar-rivers
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/environment-news-network
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/arctic-ocean
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mercury
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/coal
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rivers
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/river-pollution
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/marine-ecosystems
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/marine-life
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/canada
[13] http://admin.indiaenvironmentportal.org.in/category/thesaurus/alaska