Mercury does not remain in the body indefinitely. When the virus is no longer exposed, it takes six months to a year for it to depart the circulation. However, since mercury is stored by the liver, kidneys, and bone marrow, people who have large amounts of this metal in their system may retain it for years after exposure has ended.
The only way to be sure you have eliminated mercury entirely from your body is through prolonged periods without any exposure. Because so much of it is stored in the brain, spinal cord, and blood, even small doses over time can lead to problems with cognition, vision, hearing, and motor skills. Those who work with or are exposed to mercury on a regular basis should consult with a doctor before removing it from their bodies.
People can become poisoned by mercury in three main ways: through eating fish that have been contaminated by industrial waste, spraying agricultural land with coal-derived chemicals that result in high levels of mercury being deposited in food crops, and using dental amalgam (the filling material) because it contains mercury. The U.S. government recommends that women who are pregnant or might be pregnant avoid eating seafood from the top 20 polluted sites in America. The other two methods of exposure are not recommended during pregnancy because of the risk to the fetus.
Mercury's biological half-life in the body is believed to be 30 to 60 days. The half-life of mercury in the brain is unknown, however it is predicted to be as long as 20 years.
Mercury is hazardous, and you should avoid being exposed to it for extended periods of time, yet merely handling it will not kill you. It's like smoking; it's fatal over lengthy periods of time, but you won't die if you stroll into a smokey bar and order a drink.
The skin contact that leads to absorption of mercury occurs when an individual either ingestes or comes in contact with elemental mercury or its inorganic compounds. The primary route of elimination for elemental mercury is through the fecal-oral pathway. Ingested elemental mercury is converted by digestive enzymes into mercuric chloride, which is then absorbed by enterocytes across cellular membranes. The kidney is also capable of removing small amounts of mercury from the body. Inorganic compounds such as methylmercury are absorbed directly through the skin or mucous membranes. Methylmercury is taken up by dermal cells and slowly released into the blood stream where it can reach all organs including the brain where it becomes bound to protein molecules called selenium-containing proteins found in large quantities in hair roots and spinal cords. Unlike other heavy metals, exposure to low levels of methylmercury may not cause any symptoms to appear until the patient is pregnant or planning on becoming pregnant.
Mental impairment due to mercury poisoning appears to be irreversible. Those who have significant amounts of mercury in their bodies experience neurological problems such as memory loss, vision changes, and tremors.
Mercury lingers in the environment for extended periods of time by cycling back and forth between the air and soil, changing chemical forms in the process. Inorganic elemental mercury has an estimated atmospheric lifespan of up to two years, however organic methylmercury can persist in the soil for decades. The half-life of inorganic mercury is about a hundred years.
When mercury enters the environment, it can enter water sources or air pockets within soil, which allows it to spread far and wide. It can also travel through food chains, meaning that any organism at any level of the food chain may be affected by mercury contamination. Mercury is known to harm human health through several routes of exposure, such as eating contaminated fish or breathing in mercury vapor.
Once in the soil, mercury will continue to move down into deeper layers of earth over time if there are no other sources of pollution. The half-life of mercury in soil depends on many factors such as soil type, but it has been measured at around 20 years for most soils.
In addition to entering the environment through coal mining and industrial processes, mercury also comes from natural sources such as volcanic eruptions and geothermal events. Sulfur dioxide gas released by volcanoes can combine with water to create sulfuric acid, which can then react with mercury to form soluble mercury compounds. These compounds can then be taken up by plants and converted into methylmercury, which is toxic to humans.