Methylmercury

Methylmercury's Toxic Toll



More than 60,000 children are born each year in the United States with neurodevelopmental impairments caused by exposure in the womb to methylmercury compounds, according to new estimates by an expert panel convened by the National Academy of Sciences. The panel released its 290-page review of methylmercury's toxicity earlier this month.


Many industrial processes, especially fossil-fule burning, spew inorganic mercury into the air. Once it rains down, the pollutant undergoes a chemical transformation- methylation-into a much more toxic form. Fish and other aquatic life readily pick up and store the resulting methylmercury (MeHg) in their fat. (Science News 3-9-91.p.152)




China: A Mercury Megapolluter

Mercury is a trace contaminant of most coal. The poison has been getting out, too. Studies by the Enviromental Protection Agency have found that coal-fired boilers are the biggest U.S. source of mercury pollution. They release some 40 tons of the metal into the air each year-or roughly one-third of U.S. mercury pollutition from all sources. A new study finds that China's reliance on coal burning has made that nation a world leader in mercury emissions.


Researchers at the Chinese Academy of Sciences in Changchun calculate that in 1995, the most recent year for which data are available, China spewed nearly 215 tons of mercury into the air. Another 90 tons or so ended up in cinder and ash. Electric power production proved the biggest single mercury polluter, sending more than 70 tons skyward each year. Residential coal burning released only one-quarter as much. Manufacturing sectors together released another 100 tons.


HANJING, China - One of China's lesser-known exports is a dangerous brew of soot, toxic chemicals and climate-changing gases from the smokestacks of coal-burning power plants. In early April, a dense cloud of pollutants over Northern China sailed to nearby Seoul, sweeping along dust and desert sand before wafting across the Pacific. An American satellite spotted the cloud as it crossed the West Coast.


Researchers in California, Oregon and Washington noticed specks of sulfur compounds, carbon and other byproducts of coal combustion coating the silvery surfaces of their mountaintop detectors. These microscopic particles can work their way deep into the lungs, contributing to respiratory damage, heart disease and cancer.


Filters near Lake Tahoe in the mountains of eastern California "are the darkest that we've seen" outside smoggy urban areas, said Steven S. Cliff, an atmospheric scientist at the University of California at Davis.


Unless China finds a way to clean up its coal plants and the thousands of factories that burn coal, pollution will soar both at home and abroad. The increase in global-warming gases from China's coal use will probably exceed that for all industrialized countries combined over the next 25 years, surpassing by five times the reduction in such emissions that the Kyoto Protocol seeks.


COAL'S KNOCKOUT BLOW TO KYOTO: By 2012, expected cuts in greenhouse-gas emissions under the Kyoto treaty will be swamped by emissions from a surge of new coal-fired plants built in China, India, and the United States SOURCES: UDI-PLATT'S, US ENERGY INFORMATION ADMINISTRATION, AND INDUSTRY ESTIMATES; SCOTT WALLACE - STAFF Coal Emissions Graph


New coal plants bury 'Kyoto' New greenhouse-gas emissions from China, India, and the US will swamp cuts from the Kyoto treaty.


By Mark Clayton | Staff writer of The Christian Science Monitor


So much for Kyoto.


The official treaty to curb greenhouse-gas emissions hasn't gone into effect yet and already three countries are planning to build nearly 850 new coal-fired plants, which would pump up to five times the as much carbon dioxide into the atmosphere as the Kyoto Protocol aims to reduce.


The magnitude of that imbalance is staggering. Environmentalists have long called the treaty a symbolic rather than practical victory in the fight against global warming. But even many of them do not appear aware of the coming tidal wave of greenhouse-gas emissions by nations not under Kyoto restrictions.


By 2012, the plants in three key countries - China, India, and the United States - are expected to emit as much as an extra 2.7 billion tons of carbon dioxide, according to a Monitor analysis of power-plant construction data. In contrast, Kyoto countries by that year are supposed to have cut their CO2 emissions by some 483 million tons.