Mercury pollution a step closer to being curbedDec 11 - McClatchy-Tribune Regional News - Stephanie Lee San Francisco ChronicleMercury, a neurotoxin and one of the world's most prevalent pollutants, has been a public health concern for decades. But its days as a major environmental health issue may be numbered under a new international treaty that limits its use for the first time. The U.N. treaty, known as the Minamata Convention, has been signed by about 140 countries and, in November, the United States became the first to ratify it. Ratification signifies that the treaty, after four years of negotiations, is on track to becoming official, meaning emissions from the heavy metal's use in industrial activities like coal burning will be reduced. Closer to home, mercury would be restricted in common household products such as cosmetics, lightbulbs and batteries. Experts call it an important step toward curbing mercury pollution. The treaty is named after a Japanese town whose residents suffered mercury poisoning in the mid-20th century. "While you'd like every source of mercury to be controlled -- an ideal treaty would stop all uses of mercury -- I think there are some pretty significant changes here," said Dr. Megan Schwarzman, associate director of UC Berkeley's Center for Green Chemistry and a research-scientist in the university's School of Public Health. Mercury exposure People in the United States are primarily exposed to mercury when they eat fish and shellfish that contain methylmercury, a form of mercury that is emitted into the environment by industrial activity. Pregnant women in particular are warned to avoid methylmercury, which can impair neurological development in fetuses, infants and children. Human activities emitted 1,960 metric tons of mercury into the atmosphere in 2010, according to a 2013 report by the U.N. Environment Programme. And mercury lingers in the environment for years. "To get it out of the oceans, you have to get it out of the atmosphere," Schwarzman said. "To get it out of the atmosphere, you have to get it out of ... industrial use. That gets it out of the environment, which gets it out of the food source and out of us. All of that takes decades." The biggest source of mercury emissions globally is small-scale gold mining, which produces 37 percent of it. On the rise in South America, Asia and Africa, this mining involves intentionally using mercury to separate and collect gold from rocks and soil. But studies show the practice puts miners and people who live near mines at high risk of mercury poisoning. One concern The Minamata Convention does not ban mercury from small-scale mining, an omission that concerns public health experts. The treaty does, however, encourage nations to reduce and regulate the metal's use. The treaty is stricter on another big source of mercury pollution: coal burning, which makes up about a quarter of worldwide emissions. Coal is primarily burned to generate electricity and run industrial plants. It contains small amounts of mercury, but when it is burned in large volumes, large amounts of mercury end up in the atmosphere. Within five years of ratifying the Minamata Convention, nations must require new coal-fired power plants, boilers and smelters to use the best available emission-control technologies. The pact will not require nations to force existing plants to do the same, but governments can establish emission-reduction goals for them. This rule will probably have the biggest impact on Asia, where coal burning is on the rise. At the same time, many countries have already reduced mercury emissions by enacting air-pollution controls and stringent regulations. In the U.S., for example, emissions from coal-burning at power plants have decreased from 53 metric tons in 2005 to 27 metric tons in 2010, according to the United Nations. Impact on consumers The Minamata Convention also will affect what consumers will see on store shelves in the future. Mercury is used in lightbulbs, cosmetics, switches, batteries and medical devices, to name a few. The metal can be a health hazard if those items break and leak, but it can also create environmental problems when those items are thrown away and incinerated. The treaty "provides that, over time, a range of products which may currently contain mercury will be replaced by non-mercury alternatives," said Sheila Logan, a scientist and mercury expert for the U.N. Environmental Programme, in an e-mail. Certain mercury-containing batteries, switches and relays will be banned by 2020. So will fluorescent lightbulbs of 30 watts or less with more than 5 milligrams of mercury. So will certain medical and measuring devices with mercury, like barometers, thermometers and blood pressure monitors. Soaps, creams and cosmetics with more than 1 part per million of mercury will also be banned by 2020. Mercury was historically used as a preservative in those items, but isn't widely used in them anymore. Mascara exempted The treaty makes an exception, however, for mascara and other eye-area cosmetics, which angers some consumer advocates. "It's trying to wipe mercury off the face of the planet, yet it exempts the use of mercury in certain cosmetics," said Janet Nudelman, co-founder of the Campaign for Safe Cosmetics in San Francisco. "That doesn't make any sense. That begs the question, why not get it out of mascara as well?" Logan, the U.N. scientist, said the treaty allows mercury to be used only when no "effective and safe" substitute preservatives are available. She also noted that when mercury is used as a preservative, the levels are "extremely low" and "do not result in significant human or environmental exposures." All these changes are a ways off. For the Minamata Convention to take effect in any nation, 50 countries must first ratify it. While about 140 have signed it, indicating that they will ratify it, only the U.S. has done so -- and Logan said it's not possible to predict when the other 49 will officially come on board. Still, Schwarzman said, it's a big step toward elimination. "These sorts of rules are going to exist for the laggards," she said, "the companies that aren't going to do the right thing on their own." Stephanie M. Lee is a San Francisco Chronicle staff writer. E-mail: slee@sfchronicle.com Twitter: @stephaniemlee http://www.energycentral.com/functional/news/news_detail.cfm?did=30891030& |