Mercury and mercury compounds are highly toxic substances with adverse effects on humans1, ecosystems2, and wildlife3. Initially seen as an acute, localized hazard, mercury pollution is now recognized as a global problem, threatening populations and ecosystems distant from the point source of emissions at risk from its toxic effects. As of 2019, it is ranked third in the substance priority list of the US Agency for Toxic Substances and Diseases Registry (ATSDR), just below arsenic and lead, and has been in the list of substances for “virtual elimination” since 1997.