Mercury (Hg) is a chemical element of atomic number 80. Mercury is known for being the only metal to remain in liquid form at standard room temperature and pressure. Exposure to water soluble forms of mercury such as mercuric chloride or methylmercury, inhalation of mercury vapor or simply ingesting any form of mercury may result in mercury poisoning.
Inhalation of elemental mercury vapor includes symptoms such as tremors, insomnia, memory loss and headaches. Kidney and thyroid may be affected. Mercury exposure is known to hinder brain development in children, affect the nervous system and also lead to motor control problems later in life.
Those affected by mercury poisoning may undergo chelation therapy which mobilises deposited mercury in the body to eliminate it through the urine. It has many side-effects and may even result in death. To avoid mobilization, some practitioners of chelation use strong chelators, such as selenium, taken at low doses over a long period of time.
Mercury’s unique properties have found mercury useful across many industries that make electrical and electronic switches and thermostats, CFL light bulbs, thermometers and other measuring devices, batteries, cosmetics etc. Dental amalgams are by far the largest and longest known use case of mercury. It was mentioned in a medical text from Tang dynasty written by Su Gong in 659. Use of amalgams became mainstream during the 1800s.
Though concerns were raised over the recent decades about risks of exposure to mercury, dental amalgams still remain in use across the globe. Dentists argue that it’s only when removing existing amalgam from the tooth, the patient and those around are at a greater risk of exposure to mercury vapors. Dental amalgams are made up of 50% mercury and about 25% silver and other metals. Alternatives to mercury dental amalgam exist, such as composites (most common), glass ionomers and co-polymers (modified composites). These are all effective alternatives that are generally considered more attractive than traditional amalgam. Most dental practitioners continue to charge less for mercury amalgams than for the alternatives. The speed with which dental amalgams are being replaced varies widely, and mercury use is still significant in many countries.
In 2018, EU banned the use of dental amalgams in children under the age of 15 and women who are pregnant or breastfeeding.
Mercury and mercury compounds cannot be destroyed, but only contained so that they do not circulate in the environment, endangering human beings and wildlife. When products containing mercury are discarded into the general waste stream, the mercury pollutes the environment – in waterways, wetlands, and the air – and endangers people both locally and globally. (zeromercury.org)
Drains from dentist offices and industries are under scrutiny as mercury may be washed off to the near by rivers and lakes affecting the aquatic life and communities that depend on them. Industrial run-offs have already affected much of the world’s seafood supply. Now it’s just a matter of what fish contains what level of mercury. We know mercury accumulates in the body. This sure tells us that the size of fish matters. Smaller fishes such as Anchovies, Sardines, Salmon, Shrimp etc. contain low levels of mercury and may be eaten 2 to 3 times a week. Larger ones such as Big-eye tunas, Sharks, King Mackerel and Swordfishes contain high amounts of mercury and are best to avoid. Get information on levels of mercury and other contaminants in your local rivers and lakes before planning your next fishing trip.
Minamata Convention on Mercury, Zero Mercury Working Group (ZMWG) and other organizations are fighting the fight to phase out the use of mercury globally and ultimately aiming for zero supply, demand and mining of mercury.
In March 2022, the UN declared to phase out the use of mercury as satellite propellants by 2025 under the Minamata Treaty Provisions.
