February is often the time when people start wishing for rising mercury in their thermometers here in the Northern Hemisphere. Regardless of what all the groundhogs predicted this weekend, a recent report by the United Nations Environment Programme (UNEP) confirms that mercury actually is on the rise: in the oceans, that is.
The Global Mercury Assessment 2013 reports that the top 100 meters of seawater now has twice as much mercury as it did 100 years ago. This statistic may leave you thinking, “So that’s why tuna just doesn’t taste the same as it did when I was a kid.” If that’s the case, you’re on the right track towards linking mercury in the environment with mercury in your food. That’s a good place to start but to really understand the importance of mercury in the environment, we have to go further. While I can’t lend any evidence to being able to taste mercury in your tuna (seems unlikely, given the FDA’s reported 1.816 ppm max concentration in samples), I can hopefully guide your thoughts past your plate and towards a more planetary outlook.First of all, why pay attention to rising mercury levels in the first place? It’s not healthy for you, me, or anything else that comes in contact with it either by breathing the vapors, ingesting it in food, or absorbing it directly through skin. The health effects vary depending on the type of mercury, but according to the World Health Organization(WHO) too much mercury can negatively affect your:
- Nervous system
- Digestive system
- Immune system
- Kidney function
From cognitive and behavioral effects (think: “mad as a hatter”) to kidney failure, humans (not to mention plants and animals) face some serious risks when it comes to mercury exposure. Unlike symptoms of a water overdose (yes, it’s possible–thanks, David!), some of these health effects of mercury come over time through lots of little exposures building up mercury levels in our bodies. And we’re all exposed to a certain extent. The trouble is, some people are more exposed than others.
Where is all this mercury coming from? Natural sources, mostly. Volcanoes, rocks, soil. UNEP’s Global Mercury Assessment, however, estimates that 30% of current mercury emissions each year are now coming from human activities. Of that percentage, most of the emissions can be attributed to small-scale gold mining (37%) and coal burning (24%).
Here’s where the planetary perspective comes in: local mercury emissions don’t usually stay local. Mercury coming from a coal-fired powerplant in the U.S or a small-scale gold mine in Ghana can travel locally, regionally, and globally. Some of that mercury might even end up in the Arctic, where an estimated 92% of mercury found in marine animals is from such human-generated sources, according to UNEP. The way mercury cycles through the atmosphere, the water, the soil, and the creatures who depend on those systems is complex and beyond the scope of this post. For now, check out the figure below or take yourself on an imaginary journey as a mercury molecule (How could mercury vapor travel? What could happen to it once it gets stuck to soil? How could it get into plants and animals?).
This pattern of local use and global transport is the fascinating part for me. It’s a perfect example of the intersection between environmental justice and environmental health.
Environmental Justice: “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies…. It will be achieved when everyone enjoys the same degree of protection from environmental and health hazards and equal access to the decision-making process to have a healthy environment in which to live, learn, and work.” (as defined by the EPA)
Environmental Health: “addresses all the physical, chemical, and biological factors external to a person, and all the related factors impacting behaviours. It encompasses the assessment and control of those environmental factors that can potentially affect health. It is targeted towards preventing disease and creating health-supportive environments. This definition excludes behaviour not related to environment, as well as behaviour related to the social and cultural environment, and genetics” (as defined by the WHO)
As a student in both of these disciplines, my immediate reaction to announcements about rising mercury levels and the like is to ask questions about who might be affected. Today, I’m turning these questions back to you: Who might be most affected by mercury exposure? (Hint: think lifestyle, diet, and geography). Start thinking locally then move out to the global scale. What makes these people so vulnerable? Finally, what steps are in place to make them less vulnerable? This could be as simple as behavior changes or as complicated as policies and regulations. (Stay tuned to MTSG and maybe we can work through this questions together!).
Fortunately (I hope), we’ll start hearing a bit more conversation about controlling sources of mercury and protecting those people most vulnerable to exposure. Just a couple weeks ago, 140 nations agreed to the Minamata Convention on Mercury after 4 years of negotiations. Fernando Lugris, the chair of those negotiations, is quoted in the UNEP press release as saying the landmark agreement “has been done in the name of vulnerable populations everywhere and represents an opportunity for a healthier and more sustainable century for all peoples.”
Interestingly, a part of the agreement that focuses on human health was not supported by all the countries in negotiations, including the United States, but remains in the Convention as a voluntary piece. This piece (Article 28 Bis in this summary) encourages nations to identify at-risk populations (now maybe you can help!) and to strengthen their capacity for prevention, education, and treatment of mercury exposure.
Maybe those measures will be voluntarily tagged right on to the other non-voluntary actions countries will have to take (e.g., phasing out mercury in cosmetics and other products by 2020). But what if we end up stabilizing mercury levels in the ocean, the atmosphere, and the soils over the next century but still see disproportionate exposure levels just as we do today?
The Minamata Convention, coming on the heels of the 2013 Global Mercury Assessment, is a step in the right direction for mercury exposures worldwide. There’s no question that reducing the overall level of available mercury in the environment will benefit health. Being intentional about promoting environmental justice along with environmental health, however, will take a little more effort.
Each of these 140 nations now has big decisions to make with regards to mercury. To what extent will vulnerable populations be considered and, more importantly, involved in those decisions? Hopefully we won’t see too many cycles of rising and falling mercury in our thermometers before we can start answering that question.