Defining mercury pollution
The human body utilizes certain metals in moderate quantities such as iron, for beneficial purposes. However, other metals such as mercury and lead may have toxic effects on the biological processes of humans as well as the ecosystem. Mercury in fact is understood to be the most toxic heavy metal that occurs in a liquid state at normal temperatures.
Mercury always appears in compounds and does not occur freely in nature. In its pure form, the heavy, odourless, and lustrous liquid metal can permeate into air, water, and soil. It can be released by natural sources such as by volcanoes, although it is usually present in very small amounts. However, man-made environmental pollution can cause chances of mercury exposure to be very high.
In general, mercury can occur in three forms â€“
- Organic mercury
- Inorganic mercury
- Elemental mercury
Organic mercury, or methyl mercury, i.e, pre-existing mercury in the soil or water that is processed by bacteria, can impair neurological development in foetuses, infants and children. Methyl mercury can enter the food chain through organisms containing the substanceâ€“ such as shellfish, and is especially dangerous if consumed by to-be mothers. Methyl mercury is particularly toxic due to bio-accumulation and bio-magnification. After being processed by bacteria, it can accumulate in the fatty tissues of organisms such as fishes, without leaving the body as waste or being assimilated and can lead to higher dosages as organisms are consumed at the upper levels of the food chain.
Elemental mercury is primarily consumed through the air as vapour. Inhalation could lead to headaches, cough, chest pain, tightening of chest and difficulty in breathing, with the acute effect suffering chemical pneumonitis. Some other effects include effects on emotional faculties, sensations and nerve responses and also insomnia, neuromuscular changes, and weakening of cognitive function. Inorganic mercury can occur as elemental or inorganic salts and high exposure to it can damage the gastrointestinal tract, the nervous system and the kidneys. The symptoms of high exposure to inorganic mercury are dermatitis, skin rashes, memory loss, mood swings, muscle weakness and mental disturbances (National Institute of Occupational Health, 2007).
Status in India
India is the second-largest user of mercury in the world after the US, although India does not mine or produce mercury – instead imports most of its requirements. For example, for the fiscal year 2012-13 India imported 165 tonnes of elemental mercury (S. Sinha & K.Das, 2014).
Mercury is used in various products and processes that can lead to mercury waste, releases and emissions due to anthropogenic activities in industry. Estimates of mercury waste from CFL and Chlor-alkali sectors total 304.3 tonnes per year approximately while mercury release from healthcare usage is about 26.4 tonnes per year (S. Sinha, K.Das, 2014). LED lighting however, as an energy-efficient form of lighting, is increasingly assimilating into Indiaâ€™s mainstream market due to promotion by the government and an increasing awareness among the public of its benefits. Marking a transition from conventional sources such as CFL to LED, the Indian government plans to deploy 770 million bulbs and 35 million street lights based on LED lighting by 2019 (Globe Newswire, 2017) This will reduce the mercury usage in the lighting sector.
However, the issue of wastage and release of mercury in commercial and healthcare products lacks a proper regulatory framework, or consumer awareness, and many times manufacturers are indifferent towards their environmental responsibility. The issue of mercury pollution in Kodaikanal is a case in this regard. A study of the event in Kodaikanal by K. Brigden and R. Stringer of Greenpeace in 2003 brings this to light.
A thermometer factory in Kodaikanal, Tamil Nadu was acquired by Hindustan Lever Ltd. (HLL) from Ponds India in 1998. The factory was engaged in crushing mercury contaminated glass and in mercury distillation. As mercuryâ€™s volatility leads it to vapourize and emit into the air upon exposure, the resulting inhalation and also the dermal exposure had caused many ex-workers to report against the health and safety practices in the factory, which subsequently led to its closure. The nearby soil also showed significant mercury contamination in an environmental assessment. It Â would enter the food chain through absorption by plants and thereafter, as a study carried out on lichens in the surrounding areas around Kodaikanal showed. However, although HLL agreed to remediate the facility after closing it down, the standards maintained should be much sterner for what is a pristine forest (K.Brigden & R. Stringer, 2003).
Emissions from mercury can also occur due to anthropogenic industrial activities such as coal-powered plants, and cement, smelting and oil and gas industries. These sources contribute to approximately 161.05 tonnes per year of mercury emissions with coal-powered thermal power plants contributing about 140 tonnes per year to the total (S. Sinha & K.Das, 2014).
Coal-powered thermal power plants are the second largest source of mercury pollution in India, and this occurs because coal contains mercury naturally (0.1 to 1.1 ppm in Indian coal varieties) and combustion causes emissions of mercury into the atmosphere. Once in circulation in ecosystems, mercury is never biologically degraded in a healthy manner, and its toxic and carcinogenic effects have made it the focus of much regulatory activity in this regard. Apart from recently signing the international Minamata Convention, the legislative controls exercised by the Government of India include â€“
- The Water (Prevention and Control of Pollution) Act, 1974
- The Environment Protection Act, 1986
- The Workmenâ€™s Compensation Act, 1923
- The Factories (Amendment) Act, 1987
- The Public Liability Insurance Act, 1991
- The Municipal Solid Wastes (Management and Handling) Rules, 2000
However in the absence of a dedicated policy to tackle mercury pollution, reliance needs to be routed through international laws such as those of the Minamata Convention. The United Nations Environment Programme (UNEP) initiated negotiations for an internationally binding legal agreement against mercury pollution in 2010. After meeting five timesÂ in four years, an intergovernmental committee drafted and agreed on the treaty text in January 2013, which was adopted in October 2013 in Japan. The Treaty is currently in the process of ratification by various countries (S. Sinha & K.Das, 2014). India signed up to the Minamata Convention on September 30, 2014, and although it includes the Basel Convention for controlling the trans-boundary movement and disposal of hazardous waste, the Convention does not fix any quantitative targets (Jairam Ramesh, 2014).
Given the serious health implications of mercury pollution and the fact that it does not degrade biologically in ecosystems and the lack of mitigation plans in India that are addressed specifically to address mercury pollution, there is a need for a regulatory framework designed specifically for mercury pollution. Although India is signatory to the Minamata Convention, India has yet to allocate resources and formulate an action plan that would enforce the stipulations of the Treaty. Signing the treaty implies phasing out certain products and processes that use mercury such as coal in thermal power plants, along with restrictions on exports and imports of such products. However, to truly enforce a regulative framework specifically to mitigate mercury pollution, a National Implementation Plan is necessary that takes care of the significant socio-economic impacts of implementing the plans designed in the convention. According to Toxics Link, an environmental NGO operating in India that deals with toxic waste and food safety, India could plan to follow the Minamata Convention by bringing:
- A regulation on mercury supply and trade;
- manufacturing products, import or export of mercury-added products;
- Restricting the use of mercury or mercury compounds in the manufacturing processes;
- Controlling emission from point sources; to land and water from the relevant point sources not addressed in other provisions of this Convention;
- Putting in place environmentally sound management and handling of mercury waste consisting of / containing mercury or mercury compounds and / or contaminated with mercury or mercury compounds;
- Addressing all issues related to site contamination and its impacts on human health;
- Starting the final disposal of surplus mercury (Toxics Link, 2014).