Mercury can readily combine with chlorine, sulfur, and other elements, and subsequently weather to form inorganic salts. Inorganic mercury salts can be transported in water and occur in soil. Dust containing these salts can enter the air from mining deposits of ores that contain mercury. Emissions of both elemental or inorganic mercury can occur from coal-fired power plants, burning of municipal and medical waste, and from factories that use mercury. Inorganic mercury can also enter water or soil from the weathering of rocks that contain inorganic mercury salts, and from factories or water treatment facilities that release water contaminated with mercury.
Although the use of mercury salts in consumer products, such as medicinal products, have been discontinued, inorganic mercury compounds are still being widely used in skin lightening soaps and creams. Mercuric chloride is used in photography and as a topical antiseptic and disinfectant, wood preservative, and fungicide.
In the past, mercurous chloride was widely used in medicinal products, including laxatives, worming medications, and teething powders. It has since been replaced by safer and more effective agents. Mercuric sulfide is used to color paints and is one of the red coloring agents used in tattoo dyes. Human exposure to inorganic mercury salts can occur both in occupational and environmental settings.
Occupations with higher risk of exposure to mercury and its salts include mining, electrical equipment manufacturing, and chemical and metal processing in which mercury is used.
In the general population, exposure to mercuric chloride can occur through the dermal route from the use of soaps and creams or topical antiseptics and disinfectants. Another, less well-documented, source of exposure to inorganic mercury salts among the general population is from their use in ethnic religious, magical, and ritualistic practices and in herbal remedies.
When inorganic mercury salts can become attached to airborne particles. Rain and snow deposit these particles on land. Even after mercury gets deposited on land, it often returns to the atmosphere, as a gas or associated with particles, and then redeposits elsewhere. As it cycles between the atmosphere, land, and water, mercury undergoes a series of complex chemical and physical transformations, many of which are not completely understood. Microscopic organisms can combine mercury with carbon, thus converting it from an inorganic to organic form.
Methylmercury is the most common organic mercury compound found in the environment, and is highly toxic. Learn about how people are most often exposed to methylmercury and about the adverse health effects that exposures to methylmercury can produce.
Mercury becomes a problem for the environment when it it is released from rock and ends up in the atmosphere and in water. Mercury, a liquid metal — once widely referred to as quick silver — is a naturally occurring element released by volcanoes and the weathering of rocks. But most of the mercury that is responsible for polluting Minnesota lakes and the fish that live in them originates as air pollution from coal-burning power plants. After mercury falls to Earth with rain, snow, or dust particles, bacteria convert it into a form called methylmercury.
Without this conversion, the low concentrations of mercury in the environment would not be a problem.
But methylmercury masquerades as an amino acid, so that animals retain it in their protein, and concentrations get higher and higher up the food chain. Plankton and small fish consume the methylmercury, and larger fish eat them.
Fish highest on the food chain, such as bass, walleye and northern pike, end up with mercury concentrations about a million times higher than the water in which they live. Humans and fish-eating wildlife, such as loons and otters, are then exposed to elevated concentrations of mercury from consuming the fish. From the early s until the mids, mercury concentrations in fish were declining. But in February, , the Minnesota Pollution Control Agency reported on a new study that showed mercury levels in large fish started to increase, on average, in the mids.
For reasons scientists do not fully understand, mercury concentrations in fish are significantly higher in Northeastern Minnesota than in other parts of the state, even though the atmospheric mercury being deposited on lakes is relatively uniform across the state.
Elevated exposure to mercury can harm the nervous system brain, spinal cord and nerves and the kidneys. It can cause illness or, in extreme cases, death, and it is a special concern for fetuses, infants and children, according to the Minnesota Health Department.
Mercury Background. There are two general categories of mercury: Inorganic mercury — This is an ionized form of mercury that combines with other chemical elements to create salt forms. These salts have been used in medicines and cosmetics as well as industrial applications. Elemental mercury vapor Hg0 from metallic mercury or liquid mercury is the elemental or pure form of mercury; i.
It is the primary form of mercury released into the air by natural processes, such as volcanic activity. It is used to measure pressure and temperature, as well as in electric switches. Elemental mercury is used in a number of industries, including the chloralkali and formaldehyde synthesis processes. It is generally the form of mercury that falls from the atmosphere and is turned into methylmercury by microorganisms. Organic mercury — Microorganisms in the environment can convert inorganic mercury to organic forms, most commonly methylmercury.
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