More than 140 countries, including Tanzania, have agreed on a set of legally binding measures to curb mercury pollution.
A press statement issued by the United Nations Environment Programme (Unep) yesterday said the measures were approved during a meeting held in Geneva last week.
"A treaty to start to rid the world of a notorious health-hazardous metal was agreed on January 19, this year,” the Unep spokesman Nick Nuttall was quoted in the statement as saying.
Mercury can produce a range of adverse human health effects, including permanent damage to the nervous system.
Ahead of the five-day meeting, the Unep published a report warning that developing nations were facing growing health and environmental risks from increased exposure to mercury.
It said a growth in small-scale mining and coal burning was the main reasons for the rise in emissions.
As a result of rapid industrialisation, South-East Asia was the largest regional emitter and accounted for almost half of the element's annual global emissions.
The World Health Organization (WHO) says: "Mercury is highly toxic to human health, posing a particular threat to the development of the (unborn) child and early in life.
"The inhalation of mercury vapour can produce harmful effects on the nervous, digestive and immune systems, lungs and kidneys, and may be fatal.
The statement said “inorganic salts of mercury are corrosive to the skin, eyes and gastrointestinal tract, and may induce kidney toxicity if ingested."
The Unep assessment said the concentration of mercury in the top 100m of the world's oceans had doubled over the past century, and estimated that 260 tonnes of the toxic metal had made their way from soil into rivers and lakes.
According to the agency, parts of Africa, Asia and South America could see increasing emissions of mercury into the environment, due mainly to the use of the toxic element in small-scale gold mining, and through the burning of coal for electricity generation.
Greater exposure to mercury poses a direct threat to the health of some 10-15 million people who are directly involved in small-scale gold mining, mainly in Africa, Asia and South America. An estimated 3 million women and children work in the industry.
A study carried out in mining areas of western Tanzania by an NGO known GEUS revealed that the main extraction technique was mercury and that none of the small-scale miners had any knowledge of ways to recycle the mercury.
All mining, crushing and grinding are done by hand and the ground ore is treated with metallic mercury, whereby the very fine-grained gold amalgamates with the mercury.
Large quantities of mercury are released into the environment during the amalgamation.
The analyses showed that several of the miners had very high contents of mercury in their hair. The mercury used in amalgamation poses serious health problems to the population of western Tanzania and one of the aims of the pilot project was to reveal means to reduce the release of the chemical into the environment.