Mercury Poisoning

What is Mercury Poisoning?

Mercury poisoning occurs when too much of the element mercury is ingested, often via contaminated fish or some chemicals. Mercury poisoning can result in brain damage and lung damage. Some types can enter the blood stream and be absorbed by the organs. It can be found naturally in the air, water and soil.

Mercury can take one of three forms: Elemental, like the liquid mercury found in old-style thermometers and dental fillings; Inorganic, which is in some industrial chemicals and disinfectants; and Organic, or methylmercury, which is produced from burning coal and which is ingested by some types of fish.

Methylmercury can bio-accumulate, or collect in the body. Over time, this builds up into enough mercury to cause physical symptoms. Methylmercury can also be dangerous to developing babies, as it can cause cognitive problems and abnormal neurological development.

What are the Symptoms of Mercury Poisoning?

Signs of elemental mercury ingestion may include vomiting, having a metallic taste in your mouth, coughing, shortness of breath and swollen or bleeding gums. Inorganic mercury exposure can result in burning in the throat, vomiting and bloody diarrhea.

You usually encounter organic mercury in small amounts, but long-term exposure can result in numbness or pain, trouble walking, double vision or blindness, seizures, and death.

Mercury Poisoning Causes

Most cases of mercury poisoning (also referred to as methyl-mercury poisoning) come from eating large amounts of certain types of fish. Mercury levels in fish stem from their environment and also the fish they themselves consume. Fish that consume other fish with high levels of mercury typically have the highest levels of this toxin and should be eaten in moderation.

Sharks, tile fish, king mackerel, and swordfish contain the highest amounts of mercury and should be consumed no more than once or twice per week.

Other types of fish with higher levels of mercury include:

  • Bigeye tuna
  • Marlin
  • Salmon
  • Grouper
  • Catfish
  • Anchovies
  • Snapper

Shrimp can also contain mercury and should not be consumed more than a few times per week.

Other causes of potential mercury poisoning include:

  • Dental fillings
  • Broken thermometers
  • Some types of jewelry that contain mercury
  • Skin care products made outside of the U.S.
  • Exposure to toxic air

Being aware of environmental and nutritional sources of mercury can help to prevent mercury poisoning.

How is Mercury Poisoning Treated?

First, remove the patient from any sources of mercury exposure. Then, medical professionals can remove as much of the mercury as possible. If, for example, a battery was swallowed, it can be removed surgically. Other types of mercury can be treated with activated charcoal to bind and remove it from the body. Severe cases may require respiratory assistance, blood filtering and flushing of the stomach and intestinal tract to remove as much of the chemical as possible.

Organic forms of mercury that build up over time may not be as urgent, but can also be treated with agents to absorb and remove the chemical.

Mercury Poisoning Prevention

You can prevent mercury poisoning by being aware of the types of fish and seafood that contain higher levels of this toxin and being mindful of how much fish you consume.

Pregnant women should be especially careful when consuming fish. The March of Dimes suggests that pregnant women should not consume more than 8 to 12 ounces of fish per week.

A few guidelines for consuming seafood include:

  • Avoid uncooked seafood that is refrigerated unless it is pre-cooked; canned seafood is usually safe.
  • Be sure to cook seafood to temperatures of 145F or 63C prior to consumption.
  • Pay attention to local fish and their environment; keep abreast of local fish advisories.

You can also prevent mercury poisoning at home by exercising caution and reading labels for fluorescent light bulbs, thermometers, disinfectants, and some medical devices.