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.