When you think about mercury, you probably think of broken thermometers, or maybe you don’t think of mercury. I can tell you my interests are many and varied, but mercury has long been one of them. As the daughter of a chemist, I was repeatedly warned about the dangers of mercury, which only served to increase my fascination. Did you ever give thought to Element 80? How did they get the element symbol Hg out of Mercury? It has a dubious past and slow bloom of treachery once suspected in the deaths of author Louisa May Alcott and King Charles II. This quicksilver is a liquid at room temperature, the only metal to have that property and the symbol Hg derives from Latin hydrargyrum or “water silver” 1.

Aside from the obvious dangers inherent in extracurricular thermometer breaking, mercury is under attack by the environmental regulatory community; goodbye fluorescent light bulbs. Hold the phone coal-fired power plants. A recent article in the International Journal of Environmental Research and Public Health summarizes it as a persistent and toxic element that through human activities and natural processes can be mobilized from natural deposits into the biosphere.2 Mercury is capable of traveling long distances in air masses and water currents, wherein it can undergo methylation into methyl mercury, and then biomagnify and bioaccumulate in food chains to levels that can be dangerous to humans.2 This is most commonly recognized by the layperson as a warning about consuming too much tuna fish or sushi and not consuming fish caught from various lakes, rivers, and streams across the country.

Coal-fired power plants account for about half of all manmade mercury emissions in the United States.3 The mercury becomes airborne and can fall to the ground in rain, dust, or due to gravity where it is then part of a “global cycle” and then can travel up to halfway around the globe, entering our environment and the food chain. Until now there have been no federal standards that require power plants to limit their emissions of toxic air pollutants like mercury, arsenic, and metals – despite the availability of proven control technologies, and the more than 25 years since the 1990 Clean Air Act Amendments passed.3 The EPA’s Mercury and Air Toxics Standard (MATS) rule serves to finalize standards to reduce air pollution from power plants under the 1990 Clean Air Act Amendments. This rule was the result of more than 20-years of effort to reduce power plant emissions.3 In April 2016, the EPA had issued a final finding that it is ‘appropriate and necessary to set standards for emissions of air toxics from coal- and oil-fired power plants. This finding responds to a decision by the U.S. Supreme Court that EPA must consider cost in the appropriate and necessary finding supporting the Mercury and Air Toxics Standards (MATS).’3 However, the matter was far from settled, as changes in Government Administration and new leadership at the EPA often affect how/if a standard is adopted.

The current head of the EPA, Scott Pruitt, asked judges to stay multiple rules that target power plants, specifically regulating carbon emissions and the release of toxic metals in plants’ wastewater, as well as limiting ozone emissions generated by fossil-fuel burning, essentially calling into question the future of MATS and the Clean Power Plan. However, on August 1, 2017, the U.S. Court of Appeals in the District of Columbia issued a 2-1 ruling that the EPA had unlawfully delayed implementing regulations that limit methane gas and other pollutants, a decision viewed as a victory by environmentalists; this ruling acknowledged that the EPA has the right to reconsider regulation, but not nullify it for two years while working to rewrite the rules.

The positive impact of MATS implementation will create a ripple effect felt even locally. Here in Indiana, the new standards will improve public health, prevent up to 290 premature deaths, and create billions of dollars in health benefits with reductions in both asthma and heart attacks.3 Go to the EPA’s website to see the MATS benefits by State and see how it will improve public health where you live: https://www.epa.gov/mats#whereyoulive.

1 Kean, Sam. (2010) The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements. Little Brown and Company.

2 Sundseth, K., Pacyna, J.M., Pacyna, E.G., Pirrone, N., & Thorne R.J. (2017). Global Sources and Pathways of Mercury in the Context of Human Health. Int J Environ Res Public Health, 14(1):105, Published online 2017 January 22.

3 Environmental Protection Agency: https://www.epa.gov/mats