Artisanal gold mining top concern

In recent years, the United Nations Environment Program (UNEP) has ramped up its efforts to reduce mercury pollution from a number of sources.  Some results have been excellent, including progress toward eliminating mercury releases from chlor-alkali facilities in Europe.  There has been less movement in reducing the use of mercury in the manufacture of polyvinyl chloride (PVC), particularly in the Far East.  But the most troubling persistence of mercury use is found on multiple continents where rural populations rely heavily on rudimentary gold mining. 

The lack of success so far in slowing the growth of artisanal and small-scale gold mining (ASGM) worldwide highlights the challenge of regulating highly polluting activities that occur on a very small, nonindustrial scale. (Artisanal refers to work done by hand.)  UNEP states that the 10 to 15 million people who depend on gold mining that uses mercury should not be denied one of the few means of income available to them.  Nonetheless, mercury contamination, particularly in fish, has been shown to have devastating health effects on the neurological development of fetuses and young children.   According to UNEP, an estimated 3 million women and children, mainly in Southeast Asia, sub-Saharan Africa, and South America, work as gold miners and are directly exposed to mercury.  UNEP is therefore promoting voluntary actions to introduce less-polluting mining methods. 

In addition, in Geneva in January 2013, delegates of 140 countries agreed to establish an international binding treaty to curb mercury pollution.  The treaty will enter into force once it has been ratified by at least 50 nations, a process that could take 3 to 4 years. 

2,000 tons emitted

Mercury vapors are extraordinarily mobile and once in the atmosphere can travel thousands of miles before depositing into water bodies or soil.  ASCG accounts for nearly 40 percent, or about 800 tons, of the estimated 2,000 tons of air emissions of mercury occurring globally, easily exceeding fossil-fuel combustion (24 percent), the next leading source.  To provide perspective, U.S. power plants account for only 29 tons of mercury emissions annually.  Yet, the risks from mercury are such that EPA’s proposed Mercury Air Toxics Standard (MATS) is seeking to cut those emissions by 90 percent, at an estimated annual cost of nearly $10 billion; other air pollutants will also be controlled, but mercury is by far the major target. 

ASGM also releases mercury on-site into ground and surface waters that provide sustenance to local populations.  Once in water, mercury settles into sediments, combines chemically with anaerobic organisms, and changes into methylmercury, the most dangerous form for human health.  Methylmercury normally accounts for at least 90 percent of the mercury in fish.  Also, methylmercury bioaccumulates in large fish that eat other fish.  Concentrations of methylmercury in large fish can be over a millionfold larger than in the surrounding water.

One major objective of the treaty negotiations is to bring some form of regulation to an entirely unregulated activity while accounting for the role it plays in socio-economic growth.  In the current draft of the treaty, parties would need to develop a national action plan with specific provisions, such as estimates of mercury emissions from ASGM; strategies to prevent open burning of mercury, particularly in residential areas; and educational programs.   

One exporting country

Most of the world’s estimated 600,000 tons of mercury deposits are found in a handful of countries, including China, Kyrgyzstan, Mexico, Peru, Russia, Slovenia, Spain, and Ukraine.  Primary mining (where mercury is the target ore, not extracted as a by-product) is now limited to even fewer countries, with only Kyrgyzstan still exporting.  The global mercury demand has fallen significantly in the last 50 years, from 9,000 tons a year in the 1960s to 7,000 in the 1980s and 4,000 a decade later.  In 2005, UNEP estimated the global demand at between 3,000 and 3,900 tons.  Given present trends, it appears likely that most uses of mercury will continue to decline except in ASGM and the production of vinyl chloride monomer (VCM), which together account for around 45 percent of all global demand.

Mercury use in ASGM was estimated by Mercury Watch at 1,400 tonnes in 2011, and rising gold prices are likely to increase that use.  Emissions of mercury from ASGM reported for 2010 are more than twice those reported for 2005. While the higher price of gold and increased rural poverty may indeed have caused more activity in this sector, the increased emissions estimates are thought to be explained mainly by better data.

In any event, the practice threatens the health of the workers and their families and the people downstream who eat mercury-contaminated fish or drink the water. It can also cause environmental damage that may persist for decades after mining has stopped.

Low-mercury and mercury-free methods are available, but socio-economic conditions are often barriers to the adoption of better practices.  Persuading miners to change the way they work because mercury is a threat to them and their families can be difficult, but some good examples exist.  For example, UNEP notes the Sustainable Artisanal Mining project in Mongolia.  Supported by the Swiss Development Cooperation, this endeavor promotes efforts by the Mongolian government to work with miners to develop policies and technical solutions to eliminate mercury use.   Also, UNEP launched its Global Mercury Partnerships in 2005 to promote establishment of national action plans and reduction targets, encourage collaboration and the sharing of best practices to reduce mercury use, and help initiate innovative market-based approaches.

The situation is different for VCM, which is used as a catalyst in the global PVC sector, the second largest user of mercury.  Most PVC production using mercury occurs in China.  About 800 tons of mercury are thought to have been used by this industry in China in 2012.  UNEP says the amounts emitted or released are not known. 

Draft treaty

Once a globally binding treaty or convention is in place, UNEP “hopes” that global mercury demand will decline sharply as industries that use mercury in products and processes or release it to the environment will be required to meet obligations set out in the instrument.  The current treaty language addresses seven main areas: 

• Supply of and trade in mercury,
• Use of mercury in products and industrial processes,
• Measures to reduce emissions from ASGM,
• Measures to reduce emissions from power plants and metals production facilities,
• Storage and treatment of waste containing mercury and management of contaminated sites,
• Financial and technical support for implementation of the convention, and
• Resolution of disputes.

Specifically with regard to ASGM, the treaty would require each party with ASGM within its territory to take steps to reduce and, where feasible, eliminate the use of mercury and mercury compounds in, and the releases to the environment of, mercury from such mining and processing.  Parties would develop national action plans to achieve these objectives.  Such plans would have to include the following:

• National objectives and reduction targets.
• Actions to eliminate:
  • Whole ore amalgamation.
  • Open burning of amalgam or processed amalgam.
  • Burning of amalgam in residential areas.
  • Cyanide leaching in sediment, ore, or tailings to which mercury has been added without first removing the mercury.
• Steps to facilitate the formalization or regulation of the ASGM sector.
• Baseline estimates of the quantities of mercury used and the practices employed in ASGM and processing within its territory.
• Strategies for promoting the reduction of emissions and releases of and exposure to mercury in ASGM and processing, including mercury-free methods.
• Strategies for managing or preventing the diversion of mercury and mercury compounds to use in ASGM  and processing.
• Strategies for involving stakeholders in the implementation and continuing development of the national action plan.
• A public health strategy on the exposure of ASGM and their communities to mercury.  Such a strategy should include the gathering of health data, training for healthcare workers, and awareness-raising through health facilities.
• Strategies to prevent the exposure of vulnerable populations, particularly children and women of child-bearing age and pregnant women, to mercury used in ASGM. .
• Strategies for providing information to ASG miners and affected communities.
• A schedule for the implementation of the national action plan.

Also, each party would be encouraged to include in its national action plan additional strategies to achieve its objectives, including the use or introduction of standards for mercury-free ASGM and market-based mechanisms or marketing tools.

The health risks posed by mercury are such that some have called for a “mercury-free world.”  But currently, there are no alternatives to mercury use in ASGM and the manufacture of VCM and compact fluorescent lamps (CFLs).  According to Fernando Lugris, who chairs the Intergovernmental Negotiating Committee to develop a global treaty on mercury, the international community must therefore agree on reducing avenues for mercury to escape to the environment, beginning with “formalization” of the ASGM sector.  Lugris does believe that science can develop alternatives to mercury in VCM production and CFLs.  Until such alternatives are developed, the types of improved management contemplated in the draft treaty need to be implemented to reduce mercury releases to the environment. 

Click here for the UNEP’s report, Mercury: Time to Act.

William C. Schillaci
BSchillaci@blr.com