Minamata Convention on Mercury — The Treaty That Names a Disaster
Minamata Convention on Mercury — The Treaty That Names a Disaster
The 2013 UNEP convention targeting mercury emissions, with direct consequences for ASGM
The Minamata Convention on Mercury is a multilateral environmental treaty adopted under United Nations Environment Programme (UNEP) auspices in October 2013 and entered into force in August 2017, targeting anthropogenic mercury emissions and use across the global economy. The treaty takes its name from Minamata in Japan's Kumamoto Prefecture, the site of one of the twentieth century's worst industrial-pollution disasters — the methylmercury poisoning of the Minamata Bay community by industrial discharge from the Chisso Corporation factory between the 1930s and the 1960s, which killed hundreds and caused severe neurological injury to thousands. The naming is a deliberate act of historical memory and political signalling.
The treaty's scope
The Convention addresses mercury across its lifecycle: primary mining, supply, trade, use in products and processes, emissions to air, releases to land and water, environmentally sound storage, and waste management. It establishes phase-out dates for mercury-added products such as fluorescent lamps, batteries, and certain medical devices; it bans new mercury mines and requires phase-out of existing primary mining within fifteen years of accession; it controls trade in mercury and mercury compounds; and it establishes obligations for the management of contaminated sites.
Artisanal and small-scale gold mining
The provision of greatest relevance to the gemstone trade is Article 7, which addresses artisanal and small-scale gold mining (ASGM). ASGM is the largest single source of intentional anthropogenic mercury release globally, accounting for an estimated 838 tonnes of mercury emissions annually according to UNEP's 2018 Global Mercury Assessment — more than coal-fired power generation, more than non-ferrous metals production, more than waste incineration, and more than cement production. The mercury is used in amalgamation to extract gold from ore: mercury is mixed with crushed ore, binds the gold into an amalgam, and the amalgam is then heated to vaporise the mercury and release the gold. The vaporised mercury enters the atmosphere and the resulting fallout contaminates waterways, soils, and food chains across enormous geographical areas.
The Convention requires signatory states with significant ASGM activity to develop and submit National Action Plans setting out their strategies to reduce — and where possible eliminate — mercury use in the sector. Implementation has proven difficult: ASGM is largely informal, often illegal, and concentrated in countries whose enforcement capacity is limited. The Planetary GOLD programme, the Global Environment Facility's mercury initiatives, and various NGO efforts including those of the Artisanal Gold Council have worked to introduce mercury-free extraction techniques (gravity concentration, borax flux, direct smelting) that can substitute for amalgamation.
Implications for gemstone mining
Gold and gemstones frequently co-occur in artisanal mining contexts — alluvial workings often produce both gold and coloured stones, and the same operations may move between gold and gem extraction depending on what the deposit yields and what current prices favour. Gemstone supply chains in regions with significant ASGM activity are therefore exposed to the same mercury contamination concerns that affect the gold supply chain, even where the gemstones themselves are not produced through mercury-using processes. Responsible sourcing standards including the OECD Due Diligence Guidance, the RJC Chain of Custody, and various individual brand programmes increasingly require Minamata-compliance evidence as part of the documentation expected for sourcing from affected regions.
Status
The Convention has been ratified by 147 parties as of late 2024, including the major gem-producing and consuming nations. Implementation reviews and Conferences of the Parties have driven incremental improvements in monitoring and reporting; the 2022 COP-4 in Bali expanded the list of phased-out mercury-added products and tightened reporting requirements. The medium-term outlook for ASGM mercury reduction depends substantially on whether the alternative extraction technologies can be deployed at the scale and cost required to displace amalgamation in the affected regions.