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Mercury Poisoning (cont.)

Mercury Poisoning Prevention

Prevention of mercury poisoning is difficult if the source of the mercury is unknown. Consequently, prevention of mercury poisoning begins with identifying the potential or known sources and stopping production or isolating the toxin so none will come in contact with people. These situations are usually found in industrial or environmental sources of mercury and may require both industrial and governmental assistance to design ways to prevent exposure to forms of mercury.

Mercury Poisoning Prevention at Home

At home, there are a few mercury- containing items (for example, thermometers, medical devices, some disinfectants, fluorescent light bulbs) that potentially can be the source of mercury poisoning. People are advised to read the labels on products to see if they contain mercury, have warning labels about potential toxicity, or have directions about how to dispose of a broken or non-useable product. The EPA has a detailed set of instructions about what to do and what not to do if mercury is spilled or a fluorescent bulb breaks in the home. The instructions also tell how to dispose of mercury containing products.

Mercury Poisoning Prevention - Amalgam Fillings

People are also concerned about mercury found in dental amalgam fillings. However, the CDC has stated there is no good evidence that the small amount of mercury in amalgam fillings causes harm and that removing amalgam fillings does not benefit people. However, there are several other types of dental filling material that can be used so individuals are urged to discuss choices for dental fillings with their dentist.

Mercury Poisoning Prevention - Fish and Shellfish

Fish and shellfish are usually considered to be part of a healthy diet, but almost all contain traces of methylmercury. To prevent people from getting toxic methylmercury levels from eating seafood the FDA made these recommendations:

  1. Do not eat shark, swordfish, king mackerel, or tilefish because they contain high levels of mercury.
  2. Eat up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are lower in mercury.
  3. Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
  4. Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.
  5. Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.

Women who are trying to become pregnant, who are pregnant or are breastfeeding should be especially careful about following these suggestions as the fetus, neonate and infant brain and spinal cord seems especially sensitive to all forms of mercury poisoning.

Mercury Poisoning Prevention - Vaccines

Another source of concern by people is the use of thimerosal, a mercury-containing preservative used in vaccine preparations. Except for some influenza vaccines, it is not being used in most vaccines. However, the amount of mercury in thimerosal is very low. In 2008, the CDC recommended that current flu vaccines are safe to use in pregnant women and children because they contain very little mercury.

Mercury Poisoning Outlook

The prognosis for mercury poisoning depends on many factors:

  1. The chemical form of mercury (inhalation of vapor is worse than inorganic which may be worse than organic)
  2. The dose or amount of mercury poisoning (more leads to poor outcomes or death)
  3. Age of person (fetus, neonate, and infants more susceptible to lower doses of mercury)
  4. Length of exposure (longer exposures result in poor outcomes or death)
  5. Route of exposure (inhalation is worst, followed by ingestion, and then skin exposure)
  6. Persons overall health before exposure (people with preexisting medical problems do worse than healthy people)

Early treatment of any form of mercury poisoning has a good chance of improving the prognosis (reducing tissue damage and neurological effects of the toxins). Unfortunately, if the diagnosis and subsequent treatment is delayed, which has happened often in the past, many outcomes are only fair to poor with the patient experiencing residual or profound neurological deficits. This outcome is often seen with organic mercury poisoning because exposure usually occurs over a long length of time before characteristic signs and symptoms develop.

Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care


United States Environmental Protection Agency; "Mercury."

Agency for Toxic Substances and Disease Registry; "ToxFAQs.™"

National Institute for Occupational Safety and Health; "Mercury."

MedlinePlus; "Mercury."; "Mercury Poisoning."

United States Environmental Protection Agency; "What Never to Do with a Mercury Spill."; "Toxicity, Mercury: Multimedia."

Last Reviewed 12/13/2017

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