Mercury and cyanide in gold mining

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Emissions of mercury from gold mining and the knowledge gaps about them will be investigated in order to create the knowledge needed to build tools to understand and reduce emissions and improve gold mining practices. The fate and effects of mercury released from gold mining - particularly Artisanal and Small Scale Gold Mining (ASGM) - remains poorly understood. This is despite the fact that these releases are a key concern of the forthcoming global mercury treaty (UN). The creation of a legally binding treaty was unanimously agreed to by the world's governments in February 2009 by the Governing Council of the United Nations Environment Program in Nairobi (Decision 25/5). Under the proposed treaty, ASGM is one of the areas receiving and needing the most attention. This is mainly because ASGM is estimated to release 1200 tonnes of mercury to the environment each year, second only to coal burning. Of the 12 key knowledge gaps about mercury and gold mining that I have identified and presented to the international community, I am asking for funding to support basic scientific research into the two most critical to improving practices and most synergistic to the development of the treaty. These are (i) Mercury and Cyanide interactions; and (ii) the fate of releases. Remarkably, despite the fact that mercury and cyanide are often used together in ASGM, very little is known about mercury-cyanide chemistry. What are the cyanide-mercury complexes? How long do they persist? How can they most efficiently be destroyed? What are the fate of the decay products? Can cyanide enhance mercury bioaccumulation? What technologies can best replace this practice? How does cyanide enhance air emissions? Regarding the fate of mercury released from gold mining, How much mercury is emitted from gold mining? How much of it directly enters the atmosphere versus hydrosphere? How far does it travel? How large are latent emissions from tailings? What is the speciation of mercury emitted from ASGM? Part of the outcomes of this research will populate the www.mercurywatch.org database on global mercury emissions in collaboration with the United Nations Environment Program.