The United Nations Environmental Programme (UNEP) says global emissions of mercury have remained relatively stable in the last twenty years, with 2010 emissions from human activities thought to be just under 2,000 tonnes.
It said despite improved availability of data on mercury, the emissions estimate is still subject to uncertainty and covers a range of 1010 to 4070 tons adding that together with coal burning, the use of mercury to separate metal from ore in small-scale gold mining remains the chief source of emissions worldwide.
This was stated in UNEP report entitled: "Global Mercury Assessment" and made available to the Ghana News Agency on over the weekend.
The report said annual emissions from small-scale gold mining are estimated at 727 tons, or 35 per cent of the global total.
It said 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 adding that about 3 million women and children work in the industry.
The report said mercury-free methods and other low-cost solutions for reducing emissions during gold extraction are available, but socio-economic conditions and low awareness of the risks of mercury, are barriers to adopting safer techniques.
"Artisanal and small-scale gold mining is recognized as a major challenge in efforts to reduce emissions from mercury," the reported cited Fernando Lugris (Uruguay), Chair of the Intergovernmental Negotiating Committee.
"While taking into account the impact on national development, we must move to set national goals and reduction targets
"Other efforts should work towards the formalization of the sector, which is largely unregulated, as well as reducing health risks from mercury, this could give workers greater rights under labour laws," it added.
It said coal burning is responsible for some 475 tons of mercury emissions annually, or around 24 per cent of the global total.
"Despite increased coal combustion in certain regions, more stringent regulations on pollution in several countries have contributed to reducing overall mercury emissions from coal burning and off-setting part of the emissions arising from increased industrial activity," the report said.
Other sources of mercury highlighted in the UNEP publications include: metal and cement production, through fuel extraction and combustion of fossil fuels and consumer products such as electronic devices, switches, batteries, energy-efficient light bulbs and cosmetics such as skin-lightening creams and mascara.
It said mercury contained in such goods can also enter the waste stream.
The report said plastic production - particularly the manufacture of Poly Vinyl Chloride (PVC); which is in high demand in many countries where there are extensive building projects are sources of mercury.
It said notable actions include: the UNEP Mercury Products Partnership which has set the goal of reducing demand for mercury-containing thermometers and blood pressure devices by 70 per cent by 2017 and United States of America has finalized the Mercury and Air Toxics Standard which predicts to reduce mercury emissions by 20 tonnes by 2016.
The report said European Union banned mercury exports in 2011 and the USA has just started an export ban from 1 January 2013.
It said accelerated action, such as finalizing a global and legally binding treaty, promoting the availability of low-mercury technologies amongst other measures, can support a sharp decline in demand for mercury.
The report urged governments to ensure regulatory frameworks and incentives to promote the transition to viable, safe and commercial alternatives, resulting in reduced releases of mercury and other pollutants.