It is a chemical element with atomic number 80. Its symbol (Hg) comes from the Greek hydrargyros (hydro = water, argyros = silver). It is the only metal that is liquid at normal temperatures. It is found naturally in certain rocks and mineral deposits. It is also released into the atmosphere uncommonly in volcanic eruptions and forest fires.
A small amount of mercury comes from natural sources, this number has remained relatively constant over time. However, mercury levels available in the air, water and land are increasing due to various human activities that release mercury from its stable natural state. Humans have been isolating and using mercury from before the industrial revolution more than 200 years ago. Currently it is being released in significant quantities mainly due to the production of coal power.
Coal power plants produce most of the airborne mercury, but other industrial processes also contribute to pollution. Other sources of mercury air include gold mining, production and metal recycling, waste incineration and the manufacture of cement, chlorine and PVC.
Mercury suspended in the air can travel long distances in the wind. When it rains, the water carries mercury from air to soil, rivers and the sea. Microorganisms absorb it and thus enters the food chain. A fish that feeds on contaminated microorganisms consume a greater amount of mercury because it consumes many microorganisms. This mercury is concentrated in your body. Then another bigger fish eats the smaller species and to satisfy your hunger, eat a large number of fish. So the big fish still consumes a greater amount of mercury and this concentrates more on her body. With each link in the food chain mercury concentration is higher. Finally, the mercury reaches our plate when we eat fish, shellfish or other food that has been part of this chain.
Mercury is used in dental amalgams and vaccines containing a preservative called thimerosal. Mercury is a common material in batteries, thermometers, automotive parts, electronics, fluorescent bulbs, rat poison, insecticides, cosmetics, some types of nasal spray and certain antiseptics.
Mercury is highly toxic, primarily affecting the nervous system. It can cause tremors, muscle contractions, headache, insomnia, muscle weakness and atrophy, memory problems, lack of coordination, slurred speech and hearing, sarpudillo and emotional changes such as nervousness and irritability. Mercury poisoning can happen when a person is exposed to a large amount of mercury in a specific occasion (such as an accident) or when there is a prolonged contact with smaller amounts. Pregnant and lactating women should avoid any contact with mercury, because fetuses and babies are extremely sensitive to contamination and very small amounts can affect development of the nervous system, including the brain.