Last month, the Lancet Commission on Pollution and Health released a striking report estimating that pollution caused 9 million deaths worldwide in 2015 – 3 times more deaths than caused by AIDS, tuberculosis, and malaria combined. Air pollution was responsible for the vast majority of these deaths, but water and chemical pollution also contributed substantial burdens.
One of the chemical pollutants highlighted by the Lancet Commission is mercury, a known neurotoxicant. The report discusses the dangers of mercury when used specifically in small-scale gold mining in low-income countries, yet populations across the world can also be exposed through fish consumption or consumer products, among other sources.
Well before the new Lancet report was released, the international community had recognized the dangers of mercury and had been working to develop policies to minimize exposure to this pollutant. In fact, on August 16, 2017, after sixteen years of work and negotiations, the Minamata Convention on Mercury entered into force.
This global treaty aims to protect human health and the environment from the toxic effects of mercury through restriction of mercury products and processes. It is the first new international convention in almost 10 years focused specifically on health and the environment. (Other previous treaties include the Basel Convention for hazardous waste, the Rotterdam Convention for pesticides and industrial chemicals, and the Stockholm Convention for highly persistent global pollutants).
The convention is named after the decades-long environmental health tragedy in Minamata, Japan. Residents and animals in this area developed severe neurological syndromes after eating seafood that had been highly contaminated with mercury from industrial pollution.
Mercury is a naturally occurring metal, and certain chemical forms (specifically, methylmercury and metallic mercury vapor) are highly toxic. According to the World Health Organization (WHO), mercury is one of the top ten chemicals of public health concern. The nervous system – and in particular, the developing brain – is highly vulnerable to mercury. Exposure can result in permanent neurological damage. (Remember the Mad Hatter from Alice In Wonderland?) Other organ systems, such as the lungs, kidneys, and immune systems, may also be affected. The United Nations Environment Programme (UNEP) has stated that there is no safe level of mercury exposure.
How Are We Exposed Today?
Mercury is emitted through both natural and industrial processes. Examples of natural processes that release mercury include rock weathering, forest fires, and volcanic eruptions.
However, this global treaty targets mercury from industrial and human processes. These include coal burning, waste incineration, consumer products, and small-scale gold mining. Because mercury emissions travel through air and water without regard to political borders, only an international treaty could truly be effective in addressing this pollutant.
Human exposure to mercury occurs through several possible routes, including consumption of contaminated fish, inhalation of mercury vapors from the air, or even from the use of mercury in dental fillings.
The 84 countries that have already ratified the treaty (and the many other countries anticipated to fully join in the near future) will be required to take the following steps by 2020:
- Phase-out or reduce mercury from products such as batteries, certain light bulbs, cosmetics, and pesticides
- Control mercury air emissions from coal-fired power plants, waste incineration, and related industrial processes
- Reduce or eliminate the use of mercury in small-scale gold mining
- Reduce or eliminate the use of mercury in chemical manufacturing processes
The convention also provides guidance for safe storage of mercury, waste disposal, and contaminated sites.
Threats to U.S. progress and compliance
The U.S. Environmental Protection Agency (EPA) aims to address mercury pollution through numerous programs and regulations. But now, some of those efforts are under attack or subject to delay – threatening our prospects for reducing mercury exposure and complying with the convention.
For example, the Mercury and Air Toxics Standards (MATS) rule, passed under the Obama administration, limits the amount of mercury released from coal-fired power plants. The D.C. Circuit Court of Appeals had planned to review the cost-benefit analysis for this regulation but recently decided to delay the case instead. The Trump administration may actually decide to repeal the regulation altogether rather than defend the rule in court.
The administration’s vocal support for revitalizing the coal industry and the proposed repeal of the Clean Power Plan would further reverse progress that we have made in reducing mercury emissions. Recent shifts away from coal in this country have led to decreased mercury emissions and declining mercury contamination in tuna – historically, a significant exposure route for the population.
The current administration may also review a 2015 rule that set standards for disposal of coal ash, a byproduct of coal combustion. Improper disposal of coal ash in landfills can result in release of mercury, among other toxic chemicals.
These steps are hugely disappointing. Tackling this global pollution problem requires global action, and therefore the U.S. must continue to take strong steps to reduce mercury use and releases.
During these tumultuous times in particular, the ratification of this global treaty is an important victory for human health and the environment – and a reminder that we can still come together to make progress towards global health and sustainability. But, the realization of these goals requires political will and cooperation from all parties, and only time will tell if they can follow through on these targets.
United Nations Environment Programme. Minamata Convention on Mercury. Geneva, Switzerland: Text agreed upon in UNEP(DTIE)/Hg/INC.5/3; January 13-19, 2013. Text available here: http://www.mercuryconvention.org/Portals/11/documents/conventionText/Minamata%20Convention%20on%20Mercury_e.pdf
Landrigan et al, 2017. The Lancet Commission on pollution and health. The Lancet. http://dx.doi.org/10.1016/S0140-6736(17)32345-0