How is mercury made

Long-term exposure to mercury vapor produces shaking, irritability, insomnia, confusion, excessive salivation, and other debilitating effects. In normal situations, most exposure to mercury comes from the ingestion of certain foods, such as fish, in which the mercury has accumulated at high levels.

Although mercury is not absorbed in great quantities when passing through the human digestive system, ingestion over a long period of time has been shown to have cumulative effects. In industrial situations, mercury exposure is a far more serious hazard. Mining and processing mercury ore can expose workers to mercury vapor as well as to direct contact with the skin. The production of chlorine and caustic soda can also cause significant mercury exposure hazards.

Dentists and dental assistants can be exposed to mercury while preparing and placing mercury amalgam fillings. Because mercury poses a serious health hazard, its use and release to the environment has come under increasingly tight restrictions. This included mercury released by mercury mining and refining, various manufacturing operations, the combustion of coal, the discarding of municipal refuse and sewage sludge, and other sources. The EPA has set a goal of reducing the level of mercury found in municipal refuse from 1.

This is to be accomplished by decreasing the use of mercury in products and increasing the diversion of mercury from municipal refuse through recycling. Mercury is still an important component in many products and processes, although its use is expected to continue to decline.

Improved handling and recycling of mercury are expected to significantly reduce its release to the environment and thereby reduce its health hazard. Brady, George S. Clauser, and John A. Materials Handbook, 14th Edition. McGraw-Hill, Heiserman, David L. Exploring Chemical Elements and Their Compounds. TAB Books, Kroschwitz, Jacqueline I. Encyclopedia of Chemical Technology, 4th edition.

John Wiley and Sons, Inc. Stwertka, Albert. A Guide to the Elements. Oxford University Press, Raloff, J. Both volcanoes and forest fires send mercury into the atmosphere.

Human activities, however, are responsible for much of the mercury that is released into the environment. The burning of coal, oil and wood as fuel can cause mercury to become airborne, as can burning wastes that contain mercury. The amount of mercury deposited in a given area depends on how much mercury is released from local, regional, national, and international sources.

Since mercury occurs naturally in coal and other fossil fuels, when people burn these fuels for energy, the mercury becomes airborne and goes into the atmosphere. In the United States, power plants that burn coal to create electricity are the largest source of emissions; they account for about 44 percent of all manmade mercury emissions Source: National Emissions Inventory, version 2, Technical Support Document July pp, 10 MB, About PDF ; discussion starts on page of the PDF document.

The burning of municipal and medical waste was once a major source of mercury emissions. You can view a chart showing the annual amount of emissions of mercury and mercury compounds into the air from facilities throughout the United States from to Depending on these factors, mercury in the atmosphere can be transported over a range of distances -- anywhere from a few feet from its source, to halfway around the globe -- before it is deposited in soil or water.

Mercury that remains in the air for prolonged periods of time and travels across continents is said to be in the "global cycle. One major source of mercury emissions outside of the U. The main way that people are exposed to mercury is by eating fish and shellfish that have high levels of methylmercury, a highly toxic form of mercury, in their tissues.

A less common way people are exposed to mercury is breathing mercury vapor. This can happen when mercury is released from a container, or from a product or device that breaks. If the mercury is not immediately contained or cleaned up, it can evaporate, becoming an invisible, odorless, toxic vapor.

Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages. 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. The Minnesota Health Department encourages people to include fish as a regular part of their diet, but to consult consumption advice that is available and to choose fish that are low in contaminants.

The agency offers general statewide fish-consumption advisories, as well as specific lake-by-lake advisories for lakes where fish have been tested for mercury. The higher the temperature, the more vapours will be released from liquid metallic mercury. Some people who have breathed mercury vapours report a metallic taste in their mouths. Mercury is mined as mercuric sulphide cinnabar ore. Through history, deposits of cinnabar have been the source ores for commercial mining of metallic mercury.

This vaporises the mercury in the ore, and the vapours are then captured and cooled to form the liquid metal mercury. These mercury compounds are also called mercury salts. Most inorganic mercury compounds are white powders or crystals, except for mercuric sulphide, which is red and turns black after exposure to light. Some mercury salts such as HgCl 2 are sufficiently volatile to exist as an atmospheric gas.

However, the water solubility and chemical reactivity of these inorganic or divalent mercury gases lead to much more rapid deposition from the atmosphere than for elemental mercury. This results in significantly shorter atmospheric lifetimes for these divalent mercury gases than for the elemental mercury gas. When mercury combines with carbon, the compounds formed are called "organic" mercury compounds or organomercurials. There is a potentially large number of organic mercury compounds such as dimethylmercury , phenylmercury , ethylmercury and methylmercury ; however, by far the most common organic mercury compound in the environment is methylmercury.

Like the inorganic mercuric compounds , both methylmercury and phenylmercury exist as "salts" for example, methylmercuric chloride or phenylmercuric acetate.