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UNEP

A new treaty to control mercury…could be good for climate too

Laurent Granier's picture

courtesy: UNEP

Early in the morning on Saturday, January 19, 2013, negotiators from around 140 countries completed negotiations for the Mercury Treaty that will be adopted later this year in Japan. It will be known as the Minamata Convention, in deference to the victims of mercury poisoning from industrial pollution that occurred when residents of the Minamata Bay ingested contaminated fish and shellfish in the 1950s.

The Convention that took four years to negotiate under the auspices of the United Nations Environment Programme (UNEP) joins the ranks of a number of treaties that address chemicals and wastes. It is the first treaty to specifically address heavy metals.

Why is the international community concerned about mercury? Mercury is typically released into the environment in metallic, or “elemental”, form, or as an inorganic salt. In elemental form, it easily vaporises and can be transported great distances worldwide.  When deposited in the environment, mercury eventually can be transformed to its organic forms, including Methylmercury, which is highly toxic and readily accumulates and bioconcentrates in animals and humans. Eventually, mercury settles in cold climates and bioconcentrates up the food chains to the point that Indigenous Peoples in the North that rely on traditional foods are exposed to damaging high levels.

One of the reasons heavy metals are difficult to address is that they are mobilised through human activities, but they are also released in the environment through natural processes, for example through volcanic eruptions or in deep-sea vents. Nevertheless, estimates are that at any given time, 90% of the mercury cycling in the environment is linked to human activities – hence the need for action. The recently released UNEP Global Mercury Assessment 2013 outlines major sources of emissions, geographic and temporal trends, and behaviour in the environment. 

Moreover, international action is warranted because of the transboundary dimension of the issue. In the United States for example, it is estimated that half the mercury in fish caught in rivers comes from anthropogenic Continental sources – predominantly from coal burning – whilst the other half represents emissions from Asia. At the same time, by some estimates, approximately 50% of US releases are deposited beyond the country’s border. This is textbook justification for international action.