By JOHN HEILPRINGENEVA (AP) â¿¿ Delegates from more than 130 nations began a final round of negotiations on Sunday that are expected to lead to the creation of the first legally binding international treaty to reduce mercury emissions. The treaty would set enforceable limits on the emissions of mercury, a highly-toxic metal that is widely used in chemical production and small-scale mining, particularly artisanal gold production. Swiss diplomat Franz Perrez, whose nations helped prompt the call for the treaty, told reporters on Sunday in Geneva that "we are confident that we'll be able to conclude here this week" with a final document that nations will adopt later this year. Fernando Lugris of Uruguay, who chairs the negotiations, said the six-day conference that has drawn almost 900 delegates and dozens of non-governmental organizations from around the world already has agreed on a draft text to be used this week for negotiations. The U.N. environment program reported last week that mercury pollution in the top layer of the world's oceans has doubled in the past century, part of a man-made problem that will require international cooperation to fix. The report by the U.N. Environment Program, which is helping to sponsor the treaty talks, showed for the first time that hundreds of tons of mercury have leaked from the soil into rivers and lakes around the world. Communities in developing countries face increasing health and environmental risks linked to exposure to mercury, which comes from sources such as coal burning and the use of mercury to separate metal from ore in small-scale gold mining, the U.N. agency says. About 70 countries are involved in so-called artisanal gold mining, putting up to 15 million miners at risk of exposure to mercury, including 3 million women and children, said David Piper of the U.N. Environment Program.