Methylmercury poisoning

What is Methylmercury Poisoning?

Methylmercury poisoning is a type of poisoning caused by the ingestion of mercury in the form of methylmercury, a toxic form of mercury found in some fish and other seafood products and in some industrial products. This type of poisoning can result in a range of health effects, both short-term and long-term.

Types of Methylmercury Poisoning

There are two types of methylmercury poisoning: acute and chronic.

Acute Methylmercury Poisoning

Acute methylmercury poisoning occurs when a person consumes a large amount of methylmercury in a short period of time. Symptoms may include:
  • Nausea
  • Vomiting
  • Diarrhea
  • Stomach pain
  • Headache
  • Loss of coordination and balance
  • Blindness
  • Memory problems
  • Changes in mood or behavior
  • Muscle weakness
  • Difficulty speaking

Chronic Methylmercury Poisoning

Chronic methylmercury poisoning occurs when a person is exposed to very small amounts of methylmercury on a regular basis. Symptoms are often more severe than in acute poisoning and may include:
  • Lack of coordination
  • Shaking and tremors
  • Difficulty walking
  • Difficulty speaking
  • Paralysis
  • Blindness
  • Mood or personality changes, including depression
  • Loss of memory
  • Impaired hearing
  • Brain damage
  • Immune system problems

Causes of Methylmercury Poisoning

Methylmercury is found naturally in the environment, usually in low levels. The main source of methylmercury exposure for most people is from eating contaminated fish and other seafood products. Methylmercury can also be found in other products, including some industrial products.

Risks of Methylmercury Poisoning

The risks of methylmercury poisoning depend on the amount of mercury and duration of exposure. People who eat contaminated seafood several times a week are most at risk for poisoning. Young children are particularly vulnerable to the effects of methylmercury poisoning because their brains are still developing. Pregnant women and their unborn children are also at risk for methylmercury poisoning. Methylmercury can cross the placenta and can affect the development of the fetus, causing brain damage and other health problems.

Prevention of Methylmercury Poisoning

The best way to prevent methylmercury poisoning is to avoid eating fish and seafood that are high in mercury, such as shark, swordfish, king mackerel, and tilefish. Lower-mercury fish and seafood, such as salmon, canned light tuna, shrimp, pollock, and catfish are safe to eat in moderation. Pregnant women, nursing mothers, and young children should avoid eating high-mercury fish altogether. 

Treatment of Methylmercury Poisoning

The treatment for methylmercury poisoning varies depending on the severity of the poisoning. In mild cases, treatment may involve medications to reduce symptoms. In more severe cases, hospitalization may be required.

Some studies suggest that a chelating agent, which is a medication that binds to mercury and helps remove it from the body, may be used to treat methylmercury poisoning. However, more research is needed to determine if chelating agents are safe and effective for this purpose.