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A Toxics-Free Future

Neither gone nor forgotten: Fighting mercury 40 years on

Photo Credit: Global Environment Facility. Artisanal small-scale gold mining is responsible for up to 35% of anthropogenic mercury emissions.

The tragedy of Minamata may be a thing of the past for many, but as the world unites to take action on mercury pollution the dangers remain all too real.

At first it was a mystery. Three young girls stricken with an unknown disease in April of 1956, slurring their words, struggling to walk and suffering unexplained convulsions. Soon there were eight patients. By October there were 40 – 14 of whom had died. And the numbers kept growing.

In time, this "unknown disease of the central nervous system" would claim the lives of some 900 citizens of the Japanese town of Minamata, with 2,265 people eventually certified as suffering from mercury poisoning, in what is remembered as one of the world’s greatest environmental disasters.

Today, the legacy of Minamata lives on, with the global Minamata Convention on Mercury coming into effect on August 16. With 128 signatory nations, the convention is an historic example of international cooperation –  a united effort to free the world of a threat that affects us all.

"The Minamata Convention shows that our global work to protect our planet and its people can continue to bring nations together,” says UN Environment Executive Director Erik Solheim. “We did it for the Ozone layer, we're doing it for mercury poisoning, just as we need to do it for climate change. Together, we are cleaning up our act.”

It’s a big act to clean up though. And recent research is showing just how far-reaching the mercury threat is. A 2017 study from IPEN, UN Environment and the Biodiversity Research Institute has found mercury levels in women from the Pacific Islands as high as 11 times the 1 ppm (parts per million) threshold for negative health effects. The culprit?  A diet rich in fish.

From polluter to plate

“The information revealed to us that Pacific Island women appear to be at significant threat of mercury contamination through their food chain – through their fish supply,” IPEN researcher Lee Bell says. “What was surprising to me that it was so consistent across all of the different islands where we sampled, which shows there is a global deposition of mercury to oceans and that where people eat a lot of fish they are being impacted by those mercury emissions.”

The study analysed hair samples from women of child-bearing age from four Pacific Island nations, contrasting these with samples from as far away as Nepal and Tajikistan. The results are startling, with 96% of Pacific Island women sampled exceeding the 1 ppm threshold, despite their relatively pristine environment. In contrast, women from Nepal averaged mercury levels of 0.67 ppm, and those from Tajikistan just 0.068 ppm, despite exposure to industrial sources of mercury releases such as waste incinerators, coal-fired power plants, metallurgy plants and cement kilns.

The problem is bioaccumulation. As inorganic mercury in our air, soil and water enters the oceans, aquatic microbes convert it to methylmercury – a form readily absorbed by sea life. From bacteria, to plankton, to invertebrates, to fish, to predatory fish such as marlin and tuna – at every step in the food chain methylmercury loads increase, until they reach levels as much as half a million times higher than in the water. And at the top of that food chain, more often than not, is us.

“What it tells us is that we need to dramatically alter and reduce mercury pollution and emission sources – particularly from developed countries, but also from developing countries – as these all contribute to the global deposition of mercury to oceans and those impacts on fish,” Bell says. “So we need to ensure that all countries who have ratified the Minamata Convention endeavour to take very strong action to reduce their mercury emissions as soon as possible.”

Taking the long view

Mercury releases from human activities have doubled the amount of mercury in the top 100 metres of our oceans in the last 100 years, and we continue to release an estimated 2,960 tons every year. With a potential lead time of many years before these releases are absorbed by the environment and re-released in forms that are damaging to human health, mercury is a long-term problem we need to confront now.

“The time scale is a big issue because it makes it more difficult to measure the impact of the convention. So it’s going to take time for reduced levels in the environment to make their way to human health impacts,” Ken Davis of UN Environment’s Global Mercury Partnership says.

“It’s actually analogous to greenhouse gases – greenhouse gases stay in the environment for a long time and induce warming for decades, hundreds of years in some cases. When mercury is emitted into the environment it can cycle and can impact health and ecosystems for a long time – so the sooner we reduce emissions the more those long-term impacts will be reduced.”

The Minamata Convention is the world’s first multilateral environmental agreement to protect the environment and human health in close to a decade. Its 74 Parties have committed themselves to take action on mercury throughout its lifecycle – from banning new mercury mines, to phasing out existing mining, regulating the use of mercury in polluting industries and working together to safely process and dispose of mercury in consumer products from lightbulbs, to batteries and household appliances.

Supporting the Convention is the Global Environment Facility (GEF), the world’s largest public funder of projects to improve the global environment. Along with funding the convention itself, the GEF is supporting international, regional and country-level projects to combat mercury pollution, from developing initial assessments and national action plans on mercury use to transforming practices in the biggest emitting industries, such as artisanal and small-scale gold mining.

 “I am delighted to join others in the international community and celebrate the entry into force of the Minamata Convention on Mercury,” says GEF CEO and Chairperson Naoko Ishii. “It is a honour for the Global Environment Facility to be tasked with providing grants for projects and programmes to reduce and eliminate the use of mercury. We are ready to continue to help countries conducting inventories, implementation plans, and investments in technology to make mercury history.”

Principal Coordinator of the Minamata Convention interim secretariat, Jacob Duer, underlined the high hopes of the international community for the agreement, saying: “The 16th of August 2017 will be remembered as the day that the efforts of the global community bore eternal fruit in the protection of human health and the environment from the harmful effects of mercury.”

The challenge is clear, but so is the will to confront it. And with the Minamata Convention uniting governments and industry around the world, more than 40 years after the tragedy that it honours, a mercury-free future is finally in sight.

For further information: mercury.chemicals[at]

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