Mercury Poisoning: What You Should Know

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Mercury is a heavy metal found in nature and exists in small doses in many household products. Mercury poisoning can occur when someone comes in contact with or ingests too much mercury.

In minimal doses, mercury is generally considered safe. However, mercury is a known neurotoxin that can cause many adverse health effects in higher amounts. The most common form of mercury poisoning occurs from consuming fish and seafood containing high levels of mercury.

This article provides an overview of mercury poisoning, symptoms, complications, diagnosis, and treatment.

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Causes and Symptoms

Mercury is a neurotoxin that can damage nerve tissue in the body and negatively affect nervous system function. There are different types of mercury poisoning with different symptoms.

Methylmercury

One of the most common types of mercury poisoning comes from exposure to methylmercury. This most commonly occurs when people eat fish or shellfish containing high amounts of methylmercury.

Symptoms of methylmercury poisoning may include:

  • Muscle weakness
  • Loss of coordination
  • Loss of peripheral vision (side vision)
  • Prickling sensation in the hands, feet, or around the mouth
  • Impairment of speech or hearing
  • Difficulty walking

Metallic Mercury

Another type of mercury poisoning can occur from exposure to vapor from metallic mercury.

This type can occur when metallic mercury breaks or spills and the vapors become exposed to air. Metallic mercury can be found in dental fillings, thermostats, jewelry, and school laboratories.

Breathing in this type of mercury vapor can cause:

  • Tremors
  • Emotional changes
  • Sleeping difficulties
  • Weakness, muscle twitching, or atrophy (loss of muscle tissue)
  • Headaches
  • Changes in nerve responses
  • Poor thinking ability
  • Impaired kidney function, respiratory issues, or even death (when at high levels)

Other Types of Mercury

Inorganic mercury can sometimes be found in everyday household products such as fungicides, preservatives, antiseptics, skin-lightening products, and anti-aging products.

This type of mercury exposure occurs by being absorbed through the gastrointestinal tract and kidneys and may cause:

  • Skin rashes
  • Muscle weakness
  • Mood swings
  • Memory loss
  • Mental disturbances

Effects on Infants and Children

Methylmercury exposure can harm infants in the womb when their mothers consume fish or seafood with high mercury levels. This exposure can negatively affect brain and nervous system development.

Children who have been exposed to methylmercury before birth have been known to have difficulties with:

  • Cognitive thinking
  • Attention
  • Language
  • Fine motor skills
  • Visual-spatial skills

High levels of prenatal mercury poisoning can also cause a form of cerebral palsy, a group of disorders affecting movement, posture, and muscle tone. Lower doses during pregnancy are more likely to cause neurodevelopmental or cognitive delays.

Mercury poisoning symptoms occurring in children after birth may include:

Diagnosis

Mercury poisoning can be diagnosed with a blood test, urine test, or hair test (for long-term mercury exposure). You will need to see your healthcare provider, who will likely perform a physical exam, ask about your symptoms, and gather information about your past medical history.

Methylmercury positioning—from eating fish and seafood high in mercery—requires a blood test for diagnosis. Urine mercury levels do not help determine this type of mercury poisoning.

Treatment

The first step for treatment requires identifying the source of mercury exposure and removing it.

People with high levels of mercury poisoning in the blood may also be prescribed chelation therapy. Chelation therapy is a medical procedure that involves using chemicals or medications to remove heavy metals and other substances from the body.

A chelating agent can be injected directly into the bloodstream through an IV (intravenous drip) or given as a pill by mouth. The chelating agent binds to mercury and other toxins and exits the body through urination.

Summary

Mercury is a neurotoxin that can cause many adverse health effects at high levels. The most common form of mercury poisoning occurs from consuming high-mercury fish and seafood.

Mercury can damage the nervous system and cause symptoms such as muscle weakness, loss of coordination and peripheral vision, prickling sensations, and more. Methylmercury exposure can negatively affect infants in the womb and adversely affect their brain and nervous system development.

A Word From Verywell

Mercury poisoning can cause many adverse health effects, but there are preventive measures you can take to avoid it. Eating a diet low in high-mercury fish and seafood, properly disposing of devices containing mercury, and being aware of everyday products that can cause mercury poisoning can help.

Fortunately, treatments are available to reverse mercury poisoning and its effects. If you are having symptoms of mercury poisoning, contact your healthcare provider for evaluation and testing.

Frequently Asked Questions

  • How can I test for mercury poisoning from fillings?

    Mercury poisoning can be diagnosed with a blood test, urine test, or hair test. You will need to see your healthcare provider, who will likely perform a physical exam, ask about your symptoms, gather information about your past medical history, and order diagnostic lab tests. There is currently no way to test mercury fillings directly.

  • Can fish give you mercury poisoning?

    One of the most common types of mercury poisoning comes from exposure to methylmercury. This most commonly occurs when people eat fish or shellfish containing high amounts of methylmercury.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bernhoft RA. Mercury toxicity and treatment: a review of the literatureJ Environ Public Health. 2012;2012:460508. doi:10.1155/2012/460508

  2. U.S. Environmental Protection Agency. Health effects of exposures to mercury.

  3. Centers for Disease Control and Prevention. Organic mercury.