Some 6000 tons of mercury enter the environment each year, about a third generated by power stations and coal fires. The toxin can travel thousands of miles through the air or water. Much settles into the oceans where it enters the food chain and is concentrated in predatory fish like tuna.
Mercury is also widely used in chemical production and small-scale mining. While substitutes exist for almost all industrial processes that require mercury, more than 50 percent of mercury emissions come from coal-fueled power plants, complicating efforts to regulate it in countries that rely on coal for power.
Mercury is used in its pure form in thermometers and barometers. Many batteries contain mercury. It is used in floodlights, streetlights, and other outdoor or powerful lights. It is used to conduct electricity (i.e. thermostats) and in dental amalgams. Mercuric chloride is used in the manufacture of disinfectants, other chemicals, and as a catalyst. Mercuric chloride is used in photography and embalming. Mercury released into the environment is converted into methyl mercury by bacteria.
Mercury levels in the world have increased two to three times over the past 200 years.
A dramatic increase in mercury pollution in Australia has been forecast unless new recycling laws are brought in following the Federal Government’s move to promote fluorescent lighting. 99% of used fluorescent tubes and HID lamps, which contain mercury, are currently dumped in public landfill sites, causing a serious and ever-increasing mercury pollution problem.
CEO of the Australian Council of Recyclers, Ms Anne Prince, said the move to fluorescent tubes without corresponding legislation governing their disposal is an ecological disaster in the making.
"We need to be smart enough to avoid creating a mercury pollution problem in order to fix a carbon pollution problem – we need another system, and fast!” she said.
The nervous system is very sensitive to all forms of mercury. Exposure to high levels of any types of mercury can permanently damage the brain, kidneys. Effects on brain functions may result in irritability, shyness, tremors, changes in vision or hearing and memory problems. High exposures of mercury vapour may cause chest pain, shortness of breath, and a build up of fluids in the lungs (pulmonary oedema) that can be fatal. Long term exposure may cloud the eye. Contact with mercuric chloride can cause burns to the skin and permanent damage to the eyes. Mercury also accumulates in the body.
Children and foetuses are particularly vulnerable to poisoning by the toxic metal, which can cause birth defects, brain damage and peeling skin.
Mercury and mercury containing products will enter the body if we breathe in contaminated air, drink contaminated water, eat contaminated food, or have our skin come into contact with it. Mercury may be absorbed through the skin.
Last week’s landmark agreement follows on the heels of the Obama administration pledging to overturn a Bush era plan to allow some US power plants to increase mercury emissions despite the health and ecological risks. Advocacy groups that have been working on getting a global pact passed welcomed the US policy change.
Before the United States changed its position, industrialised countries including Canada, Australia, and New Zealand opposed a mercury treaty. The world's two largest commercial consumers of mercury, China and India, also resisted calls to initiate treaty negotiations. But all countries joined the United States in support at last Friday's meeting.
A forthcoming legally binding international treaty - slated to be enacted by 2013 - will reduce the intentional use of mercury in industrial processes and products and will limit emissions of the neurotoxin from coal-fired power plants and smelters, while also mandating cleanups of mercury waste sites.