A UNEP study released in January 2013 found mercury pollution in the top layer of the world’s oceans has doubled in the past century. In the past 100 years, man-made emissions have caused the amount of mercury in the top 100 metres of the world's oceans to double. Concentrations in deeper waters have increased by up to 25 percent. The study also indicates that hundreds of tons of mercury have leaked from the soil into rivers and lakes around the world. The report says an estimated 260 tonnes of mercury - previously held in soils - are being released into rivers and lakes.
The study titled Global Mercury Assessment 2013 indicates that communities in developing countries are facing increasing health and environmental risks linked to exposure to mercury. Most of the mercury contamination in Africa, Asia and South America are largely attributable to the use of the toxic element in small-scale gold mining, and through the burning of coal for electricity generation. Coal burning is responsible for some 475 tonnes of mercury emissions annually, or around 24 per cent of the global total.
Annual emissions from small-scale gold mining are estimated at 727 tonnes, or 35 per cent of the global total. 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.
Much human exposure to mercury is through the consumption of contaminated fish, making aquatic environments the critical link to human health.
The study, which provides a comprehensive breakdown of mercury emissions by region and economic sector, also highlights significant releases into the environment linked to contaminated sites and deforestation. Asia is the largest regional emitter of mercury, and accounts for just under half of all global releases.
The UNEP studies reiterates the need for swift action by governments, industry and civil society to strengthen efforts to reduce mercury emissions and releases. Delays in action, say the reports, will lead to slower recovery of ecosystems and a greater legacy of pollution.
The report highlights rising mercury levels in the Arctic which is far from its point of origination. An estimated 200 tonnes of mercury are deposited in the Arctic each year. The study points a ten-fold increase in levels of mercury in certain Arctic wildlife species in the past 150 years.
Other sources of mercury highlighted in the UNEP publications include:
- Metal and cement production, through fuel extraction and combustion of fossil fuels
- Consumer products such as electronic devices, switches, batteries, energy-efficient light bulbs and cosmetics such as skin-lightening creams and mascara.
- Mercury contained in such goods can also enter the waste stream.
- Dentistry: Around 340 tonnes of mercury are used annually to make fillings and other dental products, of which up to 100 tonnes are likely to enter the waste stream
- Plastic production - particularly the manufacture of poly vinyl chloride (PVC). PVC is in high demand in many countries where there are extensive building projects
- Chlor-alkali industry (production of chlorine and caustic soda from salt)
- Primary mining - although the practice is now limited to a handful of countries with only one (Kyrgyzstan) still exporting
To see the UNET report "Mercury: Time to Act is available" click
here © 2013, Richard Matthews. All rights reserved.
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