Minamata disease was officially recognized in May 1956. The disease was caused through the con-sumption of fish and shellfish that were contaminated by a methylmercury compound being discharged from the chemical plant of Chisso Co., Ltd. in Minamata City. Inhabitants living around the Shiranui Sea, who consumed large amounts of the fish, were affected by methylmercury poisoning ; such poisoning was since named Minamata disease, representing its mechanism of occurrence through the food chain.
In 1969, victims and their families instituted a lawsuit against the company responsible, and the court ordered the company to pay compensation for the damage caused by their illegal discharge and lack of ensuring appropriate safety measures. Following the judgment and with public awareness, safety standards for mercury levels in fish and shellfish were set at 0.4ppm of mercury and 0.3ppm of methylmercury.
In 1962, it was demonstrated that methylmercury affects the fetus through the placenta. Although the precise number is unknown, approximately 70 victims have been identified up to the present. The toxic effect of trace amounts of methylmercury accumulated in fish and shellfish on the fetus is being examined on a worldwide scale. Studies conducted in each country have reported that even 10 to 20ppm of methylmercury in a hair sample indicates certain negative effects on the fetus.
The planning of international mercury control regulations was initiated in 2011 to establish an international treaty for mercury control by 2013. Although Japan suggests naming the treaty the “Minamata Treaty”, there are some arguments against such a name in consideration of unresolved problems regarding Minamata disease.

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In order to reduce global risks from mercury, the United Nations Environmental Programme (UNEP) is leading the intergovernmental negotiation to prepare a global legally binding instrument (i.e. convention) on mercury with the goal of completing it by 2013. The negotiation started in June 2010 and the second session of the Intergovernmental Negotiating Committee (INC) was held in Chiba, Japan in January 2011. Items for discussion include the reduction and, where feasible, elimination of supply, trade, use, and release of mercury. The environmentally sound storage and waste management is also taken up. Based on the discussion at INC2, it was agreed that the UNEP Secretariat develop a draft text for the discussion at INC3. The draft was made available in July. INC3 will be held in Nairobi, Kenya at the end of October. Prior to INC3, an Asia-Pacific regional consultation was held at the end of September in Kobe, Japan. It has been decided that the Diplomatic Conference to finally adopt and sign the forthcoming convention be held in Japan in 2013. As a country experienced Minamata Disease, Japan intends to contribute positively to the negotiations so that “The Minamata Convention” can ultimately be agreed on.

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United Nations Environmental Programme (UNEP) Global Partnership for Air Transport and Fate Research (UNEP MFTP) is a UNEP activity aimed at accelerating the development of sound scientific information to address uncertainties and data gaps in global mercury cycling and its patterns, enhancing the sharing of such information among scientists and policymakers and providing the technical assistance and training to support the development of critical information. The partnership was established in 2005 led by Italy, and its members include Canada, Japan, South Africa, and the United States, along with Electric Power Plant Institute (EPRI), Natural Defense Council (NRDC), AMAP (Arctic Monitoring and Assessment Programme) Mercury experts and UNEP. The achievements of this partnership have been summarized in the areas of emission estimation, monitoring of mercury, and regional and global-scale modeling. This report explains the current information that UNEP MFTP has compiled into several documents.

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Preparation of national anthropogenic mercury emissions is one of the main themes of the new mercury convention being conducted by the United Nations Environmental Program (UNEP) as a means of enforcing global controls on mercury. World-wide mining data, mercury demands for both Japan and the world, and global mercury emissions are the main frames of reference. Japan′s total demand for mercury has reached 27000tons (-1956), equivalent to 2% of the world′s total mine production rate of 550000tons (-1900). In the 1970′s Japan consumed 1/5 of the world′s demand. This suggests that Japan may be a contributor to global mercury contamination. Global mercury emissions have been estimated at 1930 (1220-2900) tons/yr, an amount that surpasses the annual mine production of 1300ton/yr. Anthropogenic mercury emissions in Japan have been estimated at 21.3-28.3tons/yr. Contributions according to each emission source include : fossil fuel combustion at 10-14% ; iron and steel production at 14-19% ; non-ferrous metal smelting at 2-13% ; cement production at 31-42% ; waste (municipal and industrial solid waste) incineration at 8-12%. Specifically, the emissions from all these manufacturing processes combined contribute to 60% of total emissions. Also noteworthy is that municipal solid waste (MSW) incineration contributes to 1%, while in the mid-1980s mercury contents in MSW were reported to be 1-2mg/kg, suggesting that MSW may have been contributing 30-60 ton/yr before the mid-1980s.

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This paper begins by introducing the current status for discharge, disposal and storage of wastes that contain mercury in the countries of Japan, EU and USA. In Japan, the amounts for both landfilled and recovered mercury are estimated using an air emission inventory and material flow of mercury. Results show the amount of landfilled mercury to be much lower than that of recovered mercury. In the near future, the export of recovered mercury to other countries is likely to become prohibited. In such a case, surplus mercury and wastes that contain mercury will require the implementation of measures for final disposal or permanent, long-term storage, which corresponds to the mercury content in the waste. In this study, basic experiments have been conducted to determine the threshold for long-term storage from the viewpoint of mercury release into underground water. The results suggest that the threshold for wastes containing mercury specified in the Basel Convention and Sweden is reasonable at a rate of 0.1%. It will now become important to look into enhancing the scientific knowledge surrounding the long-term stability necessary for appropriate disposal and storage of mercury and the mercury that is contained in wastes.

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The mercury treaty, which is currently in the negotiation stages, is intended to cover the entire life-cycle of mercury, including its production, use, import and export, emissions into the environment, and disposal—all potential channels for exposure to mercury—in order to mitigate and prevent the adverse impacts mercury is known to have on human health and the environment. Since mercury has already been regulated under other chemical-related treaties, it is essential for this mercury treaty to provide a clear definition and scope for its regulation and to avoid the imposing of any obligations contradictory to the ones provided for in existing treaties onto participating countries. A coordination clause that would work to govern the relationship between this treaty and other existing treaties will be helpful for this purpose. Moreover, making institutional arrangements for continuous coordination, including coordination among treaty secretariats, will be necessary. It is also desirable that over the long-term, countries act to build a comprehensive framework that could manage and coordinate all chemical-related treaties.
Additionally, in regard to this proposed mercury treaty, measures that restrict trade in mercury, mercury-added products and mercury waste under negotiation are likely to be challenged as violations of WTO agreements, especially by non-parties to the mercury treaty. Such trade measures may be deemed incompatible with WTO agreements if a country restricts import from one country but allows the import of a “like product” from another country or if it allows domestic production of a “like product”. Providing conditions for using trade measures in a way that is consistent with WTO agreements is certainly worth taking into full consideration.

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