The agreement, reached among more than 140 countries, is legally binding and aims to phase out many products that use the toxic liquid metal such as batteries, thermometers and some fluorescent lamps. This will happen through the banning of global import and exports by 2020.
The treaty will require countries with coal-fired power plants such as India and China to install filters on new plants. They also have to commit to reducing emissions from existing operations to prevent mercury from coal reaching the atmosphere.
"We have reached a robust, balanced and dynamic environmental agreement," said Janez Potočnik, the EU Commissioner for the Environment.
"Whilst the EU has an overarching strategy for controlling mercury at all stages of the mercury life-cycle, such controls are unfortunately lacking in many parts of the world. This new Treaty will bring benefits to all populations around the world, including the citizens of the EU given the long distances that mercury can travel in the air," Potočnik said.
The environment commissioner added that pregnant women, infants and children are at particular risk from exposure to mercury in the food chain and the new treaty will significantly decrease their exposure to the toxic substance.
The Commission had previously stressed that pregnant women or those who are breastfeeding "should not eat more than one portion per week of large predatory fish, such as swordfish, shark, marlin and pike". Moreover, parents should be aware that young children "should not eat tuna more than twice per week", it said.
The agreement includes measures to reduce mercury use in small-scale gold mining, however, an all-out ban deal was not reached. Gold prices near $1,700 a tonne (€1,275/t) have spurred the use of mercury as a catalyst to separate gold from its ore.
Emissions of mercury from artisanal and small-scale gold mines, which are usually unofficial and often illegal, more than doubled to 727 tonnes in 2010 from 2005 levels, overtaking coal-fired power plants as the main source of pollution from the metal.
Financing an obstacle
The treaty requires governments to draw up national rules to comply and could take between three to five years to take effect.
As mercury, also known as quicksilver, is released to the air or washed into rivers and oceans, it spreads worldwide, and builds up in humans mostly through consumption of fish.
Officials said the financing required to bring in cleaner technology for industry and help developing countries come up with local solutions was one of the major sticking points of the U.N. negotiations.
Japan, Norway and Switzerland have made initial pledges totalling $3 million (€2.26mln) in financing and an interim financial arrangement will be discussed in April by the Global Environment Facility.
Many nations have already tightened laws; the United States barred exports of mercury from January 1, 2013. The EU was the main global exporter until 2008, but has since 2011 barred exports of the liquid metal.