The experts will explore options for addressing these impacts, including reducing or eliminating the use of mercury in products and industrial processes, cutting mercury emissions and releases, improving international cooperation and sharing information.

The risks of mercury poisoning and of chemicals pollution in general gained worldwide attention in the 1960s and 70s when several thousand people living on the shores of Minamata Bay in Japan sickened or died after eating seafood contaminated with mercury from a nearby factory.

"We live now in the 21st century and there can no longer be any excuse for exposing people and the natural environment to dangerous levels of toxic chemicals," said UNEP Executive Director Klaus Töpfer. "In the case of mercury - which has destroyed the lives of thousands of people - we need to make mercury poisoning a thing of the past."

Mercury is a heavy metal that comes from both natural and human sources. Once it has been released into the environment, it cycles between soils, water systems, and the atmosphere. It can travel thousands of kilometres from its point of origin, contaminating remote regions such as the Arctic. Mercury also persists in the environment for long periods of time.

Mercury transforms naturally through biological activity in aquatic environments into methylmercury, a highly toxic organic compound that is absorbed by humans and animals. Because it bio-accumulates up the food chain, the higher carnivores - especially predatory fish such as tuna and swordfish, freshwater fish such as pike and bass, and mammals such as otters, seals and whales - can accumulate large quantities in their tissue.

Most people are exposed to mercury primarily through eating fish, as well as some other foods. Responding to findings that freshwater fish as well as marine fish and seafood often contain elevated levels of mercury, a number of governments have issued health advisories to their citizens recommending limits on how many fish people should eat over certain periods of time.

Workers in industries that use mercury face additional exposure risks. Also, in recent years the use of mercury in artisanal gold mining has been polluting the local environment and affecting the health of both the gold miners and their families in an increasing number of developing countries.

Chronic, low-level exposures to mercury are known to cause permanent damage to the brain, nervous system, and kidneys. Effects on brain functioning may lead to irritability, shyness, tremors, changes in vision or hearing and memory loss. Pregnant mothers and their foetuses are particularly sensitive to the effects of mercury.

Many governments have national regulations to control mercury emissions, reduce or eliminate the use of mercury in certain products, and protect workers. Fortunately, effective substitutes for most uses of mercury are now available. Several governments have succeeded in reducing emissions and uses of mercury by as much as 75% over the past 10 or 20 years.

While mercury is released naturally from rocks, soil, and volcanoes, human activities have boosted atmospheric levels to some three times above pre-industrial levels. Estimates vary widely, but some 5,000 to 10,000 tonnes of mercury are thought to enter the atmosphere every year, 50 to 75% of it from human activities. When placed in landfills mercury can slowly seep into groundwater or evaporate into the air.

The main human-made source of mercury emissions is coal combustion from electrical power plants and industrial, commercial and residential burners. Other sources include municipal solid waste incineration, mining of non-ferrous metals, and artisanal gold mining.

Mercury has been widely used because it is an excellent conductor and is highly malleable. The most ubiquitous products include thermometers, dental fillings, fluorescent lamps and other electrical equipment, and some batteries. It has also been used as an ingredient in some pesticides and biocides, certain pharmaceuticals, and cosmetics such as skin-lightening creams. In some countries, mercury also has ritual religious uses.

The UNEP Global Mercury Assessment Working Group was established in response to a 2001 request by UNEP's Governing Council. The Group's recommendations will be forwarded to the next Governing Council meeting on 3 - 7 February 2003 at UNEP headquarters in Nairobi.

Note to journalists: UNEP Chemicals Director Jim Willis and Scientific Affairs Officer Aase Tuxen will brief the press on Monday, 9 September, at 13h15 in Room 3. For more information, please contact Michael Williams at +41-22-917 8242, +41-79-409-1528 (cellular), or Michael.Williams@unep.ch . Official documents and other information are posted at www.chem.unep.ch/mercury/ .