The fight against global toxic pollution has reached a critical milestone: the 50th country has ratified the United Nations Minamata Convention on Mercury, triggering its entry into force in August.

A 12-year-old boy shows the mercury he carries in his trousers’ pockets for gold processing in Homase, Amansie Central district, Ashanti Region, Ghana.

© 2014 Juliane Kippenberg/Human Rights Watch

Mercury is a shiny liquid metal whose largest use globally is small-scale gold mining; other areas of use include manufacturing and industrial processes. But mercury is toxic. It attacks the nervous system, can result in life-long disability, and is very harmful to children. In higher doses, it can kill.

I have seen with my own eyes how children in Ghana, the Philippines, Tanzania, and Mali have been exposed to this toxic substance. Twelve-year-old “Kwame” in Ghana showed me a small bottle of mercury he always carried with him. He mixed mercury into the ore to create a gold-mercury amalgam, and then burnt this over a fire at home to retrieve the raw gold, breathing in its toxic fumes.

The Minamata Convention brings hope for people like Kwame. It obliges governments that ratify the convention to promote mercury-free gold processing methods; take special measures to protect children from exposure; improve health care; and put an end to particularly harmful practices in gold processing, including the burning of themercury-gold amalgam in residential areas. It also provides controls in many other areas, such as mercury use in products and manufacturing processes, and unintentional emissions stemming from coal-fired power plants.

Ghana has already ratified the convention, as have other important gold mining countries such as Peru, Ecuador, Mali, and Burkina Faso, as well as donors such as the United States and Japan. On May 18, the European Union and seven member states ratified the convention, bringing the total number of ratifications over 50, the number of ratifications required for the treaty’s entry into force.

The convention is named after the Japanese fishing town of Minamata, where mercury was discharged into the bay by a large chemical company from 1932 until 1968. Japan has recognized that more than 2,955 suffered mercury poisoning as a result, but subsequently compensated about 60,000 people. The real number of victims is thought to be even higher.

It is great news for Kwame and millions of others that the Minamata Convention is about to enter into force. Now comes the hardest part: Governments need to put it into practice.