Hazards of Mercury contamination on health and environment
Mercury is a ubiquitous environmental toxin and a hazardous metal that occurs naturally in the earth’s crust. It is an element which can not even remove in water by boiling. . Three forms of mercury (elemental, inorganic, and organic) exist, and each has its own profile of toxicity. , mercury and its compounds can be found in all environment including ambient and indoor air, surface and drinking-waters, soil and sediments, biota, food and the occupational environment. Natural phenomena such as erosion and volcanic eruptions, and anthropogenic activities like metal smelting and industrial production may lead to substantial contamination of the environment with mercury. According to United States Environmental Protection Agency mercury is emitted worldwide in the range of 5,000 to 8,000 metric tons per year. From the atmosphere, mercury cycles from rainwater into lakes and oceans, where it is converted by microbial activity into organic methylmercury. When the term “methylmercury compounds” was introduced as a medical subject heading, the U.S. National Library of Medicine has listed approx 1,000 publications on experimental toxicology of this substance. At present, methylmercury is one of the environmental pollutants. It is neuro-, nephro-, and immunotoxic, it is readily transport into tissues, crosses the blood-brain barrier and also crosses the placenta.
Methylmercury accumulates in aquatic food chains and has greater potential toxicity than inorganic mercury, methylmercury concentrates in fish, then birds and mammals, including humans, who eat those fishes Through consumption of mercury in food induce many diseases and mortality including. Central nervous system defects and erethism as well as arrythmias, cardiomyopathies, and kidney damage have been associated with mercury exposure. When these fishes consumed by pregnant women may lead to neurodevelopmental problems in the developing fetus, such as mental retardation, vision and hearing loss, language disorders. Necrotizing bronchitis and pneumonitis arising from inhalation of mercury vapor can result in respiratory failure, very high mercury exposure causes paresthesias, ataxia, and sensory abnormalities, depression and other neuropsychiatric disorders in adults Elemental mercury vaporizes at room temperature. When inhaled, elemental mercury vapor easily passes through pulmonary alveolar membranes and enters the blood, where it distributes primarily to the red blood cells, central nervous system (CNS), and kidneys, . Mercury salts are also very toxic to the kidneys, causing acute tubular necrosis, immunologic glomerulonephritis, or nephrotic syndrome. Necrotizing bronchitis and pneumonitis arising from inhalation of mercury vapor.
Wildlife may be exposed to mercury and methylmercury from a variety of environmental sources, including mine tailings, industrial effluent, agricultural drainwater, impoundments, and atmospheric deposition from electric power generation. Terrestrial and aquatic wildlife may be at risk from exposure to waterborne mercury and methylmercury, which accumulates at successive trophic levels in the food chain. If high trophic level feeders, such as piscivorous birds and mammals, ingest sufficient methmercury in prey and drinking water, Hg toxicoses, including damage to nervous, excretory and reproductive systems .
Mercury is used in gold mining to extract gold from ore during this process mercury evaporates, these vapors pf mercury in the air around amalgam burning sites can be alarmingly high and almost always exceed the World Health Organization (WHO) limit for public exposure. These exposures affect not only the workers but also those in the communities surrounding the processing centers. According to WHO the inhalation of mercury vapor can produce harmful effects on the nervous, digestive, and immune systems, lungs and kidneys and may be fatal Current studies indicate that those people who are in the ASGM (Artisanal and small-scale Gold Mining) communities experience neurological effects, kidney effects, and possibly immunotoxic/autoimmune effects from mercury exposure. Elemental mercury in liquid form is found in thermometers, barometers, and other instruments. Dental amalgam, a composite metal that is about 50% mercury, used to fill decayed teeth, Fluorescent light bulbs and disk batteries also contain mercury. Indiscriminate disposal of these items is a major source of environmental mercury contamination when they are buried in landfills or burned in waste incinerators rather than recycled. EPA (Environmental Protection Agency) is working with the National Institute of Standards and Technology and stakeholders to reduce the use of mercury-containing non-fever thermometers in industrial setting . Mercury salts are very toxic to the kidneys, causing acute tubular necrosis, immunologic glomerulonephritis, or nephrotic syndrome. Central neuropathy can also occur from mercury salt exposure.
Methylmercury has been used as a fungicide on seed grains. When grain accidentally treated with a mercury fungicide causes series of food poisoning.
In conclusion mercury contamination in environment are increasing day by day this could be a major health hazard, Mercury and their compound produce adverse health effect on a global scale, fishe is an essential part of our lives and if it contaminated with mercury then it is possible that mercury would spread to human so there should be international action to reduce the contamination of mercury or substituting it with safer alternatives, and control anthropogenic releases from activities such as manufacturing, mining, and power production. Governmental and non-governmental organizations must make a turn in their approach and apply informative and educational programs, as well as make pragmatic decisions aimed at reducing mercury burden both nationally and internationally.