Some supporters of a new mercury treaty said they were not satisfied with the agreement.
Joe DiGangi, a science adviser with advocacy group IPEN, said that while the treaty is "a first step," it is not tough enough to achieve its aim of reducing overall emissions. For example, he said, there is no requirement that each country create a national plan for how it will reduce mercury emissions.
His group and some of the residents of Minamata have opposed naming the treaty for their city because they feel it does not do enough to fix the problem.
"This treaty should be called the 'Mercury Convention,' not the 'Minamata Convention," said Takeshi Yasuma, a Japanese activist. "Water pollution resulting in contaminated sediment and fish caused the Minamata tragedy, but the treaty contains no obligations to reduce mercury releases to water and no obligations to clean up contaminated sites."Treaty proponents called it a good first step, however, and Steiner said the document would evolve over time and hopefully become a stronger instrument.