Mercury has been a developing issue for several hundreds of years globally, even though some countries have banned the sale of Mercury, they have not banned the importation of the this element, over time there has been a large and intense evaluation conducted, but unfortunately very little has been achieved in education and laws to suit the stoppage of this major issue or global problem. This article gives the average person an insight into its effects, long-term and immediate effects.
What is Mercury
Mercury (chemical symbol Hg) is a heavy metal occurring on earth in various forms. It can be converted from one form to another by natural processes, and, once released, actively cycles in the environment for hundreds to thousands of years before being buried in sediment. It is well known for being the only metal that is liquid at room temperature and normal pressure. Mercury is also a potent neurotoxin with severe global human health impacts.
Once released into the environment, elemental mercury undergoes a series of complex transformations and cycles between atmosphere, ocean, and land. Consequently, there is a global ‘pool’ of mercury circulating between air, water, sediments, soil and living organisms. Inorganic mercury, meanwhile, can be converted to an organic compound, methylmercury, made of a ‘methyl group’ of hydrogen and carbon atoms plus a mercury ion.
It is by far the most common form of mercury in the food chain and is the bio-accumulative environmental toxicant responsible for the acute methylmercury poisoning seen at Minamata Bay and in several other historical instances of mercury poisoning. Methylmercury can be formed from inorganic mercury by the action of anaerobic organisms that live in aquatic systems including lakes, rivers, wetlands, sediments, soils and the open ocean. This methylation process converts inorganic mercury to methylmercury in the natural environment.
Mercury is a highly toxic, naturally occurring metal that causes significant harm to both human and ecosystem health. Mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride) or inhalation of mercury vapor, or eating seafood contaminated with mercury. When consumed, mercury produces significant adverse effects in humans and is particularly dangerous to fetuses, infants, and young children.
Mercury poisoning, or hydrargyria, is poisoning caused by exposure to the metal or its compounds, which, especially the organic ones, could be more toxic than the element itself. Effects include damage to the kidneys, liver, and lungs, but mercury is primarily a neurological poison, causing tremors, extreme mood changes and eventually loss of hearing and restricted vision.
The ‘Minamata’ Incident in the 1950s
One of the most serious incidents in the history of industrial pollution occurred on the Yatsushiro Sea coast in Japan. Over a period of almost 40 years, Chisso Corporation, a plastics manufacturer, released a total of 272 727 tons of mercury waste into the sea outside the city of Minamata. Residents, who relied heavily on fish for food, were at high risk of exposure to methylmercury with every mouthful of fish.
The high contamination levels in the people of Minamata led to severe neurological damage and killed at least 100 people, while thousands of people from the area suffered health problems or were left paralyzed or permanently disabled. This form of mercury toxicity in humans is now called Minamata disease, after the location where the first patient of the disease was identified.
In 1965, Minamata disease patients were also reported in the Agano River basin in Niigata Prefecture. Symptoms include sensory disorders, loss of feeling or numbness in the hands and feet, muscle spasms, tunnel vision or blindness, smell and hearing impairments, and disequilibrium syndrome. More serious cases lead to convulsions, seizures, paralysis, coma and possibly death.
In addition to the outbreak among adults, congenital Minamata disease was observed in babies born to affected mothers. By the end of March 2001, 2 265 persons had been officially certified as suffering Minamata disease on the Yatsushiro Sea coast and 690 persons had been certified in the Agano River basin. Approximately 144.1 billion yen has been paid as compensation from the responsible companies.
The Minamata Convention on Mercury
The global transport of mercury in the environment was a key reason for the decision that global action to address the problem of mercury pollution is required. In January 2013, the intergovernmental negotiating committee on mercury concluded its fifth session by agreeing on the text of the Minamata Convention on Mercury.
The objective of the Convention is to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds and it sets out a range of measures to meet that objective.
These include measures to control the supply and trade of mercury, including setting limitations on certain specific sources of mercury such as primary mining and to control mercury-added products and manufacturing processes in which mercury or mercury compounds are used, as well as artisanal and small-scale gold mining.
The text of the Convention includes separate articles on emissions and releases of mercury, with controls directed at reducing levels of mercury while allowing flexibility to accommodate national development plans. In addition, it contains measures on the environmentally sound interim storage of mercury and on mercury wastes, as well as contaminated sites.
Provision is made in the text for financial and technical support to developing countries and countries with economies in transition, and a financial mechanism for the provision of adequate, predictable and timely financial resources is defined.
The coordinated implementation of the obligations of the Convention will lead to an overall reduction in mercury levels in the environment over time, thus meeting the objective of the Convention to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.
Named after the worst historical case of mercury poisoning, it details a set of measures to achieve a ban on new mercury mines; the phasing out of existing ones; control measures on air emissions; control of mercury-added products and manufacturing; measures on interim mercury storage, as well as regulation of artisanal and small-scale gold mining and of the handling of dental amalgam. The Minamata Convention’s provisions are very similar to existing EU legislation on mercury; its overall goals are in line with the EU Mercury Strategy.
Artisanal Gold Mining
Artisanal gold mining is the most significant source of mercury emissions globally. Most artisanal gold miners are from socially and economically marginalized communities and turn to mine in order to escape extreme poverty, unemployment, and landlessness. One study estimated that one or two grams of metallic mercury get released into the environment for every gram of gold produced using the amalgamation process.
Artisanal small-scale gold mining (ASGM) takes place in more than 60 countries, mainly in Asia, South America, and Africa. Concentrations of mercury in the soil surface were up to 16.7 mg per kg (mg/kg) of soil in the village itself and up to 24.9 mg/kg in nearby paddy field soil, decreasing gradually further along the river. Such studies demonstrate the risk to human health and ecosystems in the vicinity of ASGM operations.
Reducing emissions from the gold mining industry under the Minamata Convention, parties with ‘more than insignificant’ ASGM and processing shall develop a national action plan outlining national objective, reduction targets, and actions to eliminate whole ore amalgamation and open burning of amalgam as well as all burning of amalgam in residential areas.
Combined with regulations that ban new processing centers in outlying areas, there is evidence that the use of retorts led to a 10% reduction in mercury concentrations in the Segovia area of Colombia, over 2010, despite a 30% increase in gold production.
Mercury Contamination in the Philippines
Artisanal gold-mining activities in the Philippines have proliferated since the early 1980s. The area of study is Apokon, Tagum, Davao del Norte, which has 29 gold processing and refining plants. A summary of physical examination results showed that the predominant findings include under-height, gingival discoloration, adenopathy, underweight and dermatologic abnormalities among children examined.
Mercury Contaminates in South Africa
Spatial patterns of Hg distribution and bioaccumulation in water resources were investigated by collecting and analyzing multimedia samples for physiochemical and Hg-species determination from 62 sampling sites. The data presented showed a wide range in concentrations, which was expected given the array of environmental parameters, water chemistry and sources of Hg.
Generally, higher Hg concentrations were measured in environmental compartments impacted by the major anthropogenic Hg sources which, in South Africa, are largely represented by emissions from coal-fired power stations (i.e. Oliphant’s and Upper Vaal WMAs) and artisanal gold mining (i.e., In Komati WMA).
A steady progress has been made in Hg research in South Africa. However, despite the substantial knowledge about Hg toxicity, there are still considerable knowledge gaps on the fate and transport of Hg. Hence, further environmental and human health studies are proposed.
Soil Erosion of Contaminated Sites
Soil erosion is one of the main causes of land degradation and is one of the most serious ecological environmental problems facing the planet. Erosion of heavily polluted land has serious ecological consequences, particularly in the case of mercury contamination, which can potentially spread and convert to methylmercury in an aquatic environment.
In a study of the seriously mercury-polluted Wanshan mining area in south-western China, researchers calculated both soil and mercury erosion levels. Using the revised universal soil loss equation (RUSLE) and geographic information systems (GIS), they showed that the soil erosion rate can be as high as 600 884 tons per km2 per year, and the mercury surface erosion load was predicted to be 505 kg per year. The situation is exacerbated by the steep landscape.
Annual global emissions and releases of mercury from the contaminated sites identified amount to, on average, 198 tons per year. Of this, 82 tons per year are emitted to the atmosphere and 116 tons per year are released into water sources. These sites thus represent a long-term source of mercury emissions and releases, if not carefully managed.
Reducing emissions from soil erosion the ability of mercury to enter rivers and streams from old mines and industrial sites is particularly important to consider when developing methods and policies to reduce emissions. The inherent problems of mercury pollution such as persistence, and changes to its chemical form, have been studied in relation to remediation actions for contaminated sites.
The researchers developed an integrated model approach to predicting releases of mercury into the atmosphere, noting that larger ‘plumes’ were generated in warm, dry weather compared to colder periods. The model can be used as a tool by environmental remediation managers to aid decision-making.
Mercury Satellite Monitoring
Satellite observations might yet become a valuable source of information, but instruments in use are far from ready for this. The European Global Mercury Observation System (GMOS) project was designed to establish a worldwide observation system for measuring atmospheric mercury in ambient air and precipitation samples.
GMOS participated in the Global Earth Observation System of Systems (GEOSS) initiative through the GEO Task HE-02 ‘Tracking Pollutants’, received funding from the EU’s 7th Framework Programme and had 23 partners across the globe. It supplied integrated information from ground-based sites, cruise and aircraft campaigns and expanded existing atmospheric monitoring capabilities to include mercury.
The mercury task group under GEOSS dealt with the sharing of data from GMOS, allowing access to comparable and long-term data from many ground-based and off-shore sites, to help understand patterns of mercury transport in time and space and possible deposition to terrestrial and aquatic ecosystems.
GEO data supported the evaluation of regional and global atmospheric mercury models for use in the analysis of different policy options for reducing mercury pollution impacts on human health and ecosystems and ultimately the policy-making process of the Minamata Convention.
GMOS completed its work in October 2015, publishing its major findings in 2016. It established a global observation system for mercury, and the resulting data were used to validate regional- and global-scale atmospheric mercury modeling systems, identify source-receptor relationships and develop interoperable tools to allow the sharing of observational data.
Conclusion
The new global treaty on mercury will help protect millions of people all over the world from exposure to this toxic heavy metal. With ratification the EU has delivered the decisive bit and triggered its entry into force. This is a great success of EU green diplomacy. It highlights Europe’s commitment to strong and concerted international action.