Health Effects of Exposures to Mercury
- the form of mercury (for example, methylmercury or elemental (metallic) mercury)
- the amount of mercury in the exposure;
- the age of the person exposed (the fetus is the most vulnerable)
- how long the exposure lasts
- how the person is exposed -- breathing, eating, skin contact, etc.
- the health of the person exposed.
- Their physician, and/or
- Their poison control center at 1-800-222-1222.
- Volume V of the 1997 Mercury Study Report to Congress, and
- the IRIS Chemical Assessment Summaries for
Effects on People of All Ages
Exposure to methylmercury most commonly occurs when people eat kinds of fish and shellfish that have high levels of methylmercury in their tissues. Almost all people have at least small amounts of methylmercury in their bodies, reflecting the widespread presence of methylmercury in the environment. U.S. Centers for Disease Control and Prevention (CDC) data show that most people have blood mercury levels below levels associated with possible health effects. Methylmercury, however, is a powerful neurotoxin, and people exposed to high levels may experience adverse health effects. If you are concerned about your exposure to methylmercury, you should consult your physician.
- loss of peripheral vision
- "pins and needles" feelings, usually in the hands, feet, and around the mouth
- lack of coordination of movements
- impairment of speech, hearing, walking
- muscle weakness
Effects on Infants and Children
Infants in the womb can be exposed to methylmercury when their mothers eat fish and shellfish that contain methylmercury. This exposure can adversely affect unborn infants' growing brains and nervous systems. These systems may be more vulnerable to methylmercury than the brains and nervous systems of adults are.
- cognitive thinking,
- fine motor skills, and
- visual spatial skills.
- Guidelines for eating fish that contain mercury
- How people are most commonly exposed to methylmercury
- Technical summary of risk assessment for methylmercury in EPA's IRIS database
Exposures to metallic mercury most often occur when metallic mercury is spilled, or when products that contain metallic mercury break, so that mercury is exposed to the air. If you are concerned about your exposure to metallic mercury, you should consult your physician.
- emotional changes (such as mood swings, irritability, nervousness, excessive shyness)
- neuromuscular changes (such as weakness, muscle atrophy, twitching)
- disturbances in sensations
- changes in nerve responses
- poor performance on tests of mental function
Higher exposures may also cause kidney effects, respiratory failure and death.
Note that metallic mercury vapor is not the same as methylmercury.
- How people are most commonly exposed to elemental (metallic) mercury
- Technical summary of risk assessment for elemental mercury in EPA's IRIS database
High exposure to inorganic mercury may result in damage to the gastrointestinal tract, the nervous system, and the kidneys. Both inorganic and organic mercury are absorbed through the gastrointestinal tract and affect other systems through this route.
- skin rashes and dermatitis,
- mood swings,
- memory loss,
- mental disturbances, and
- muscle weakness.
Some people who drink water containing inorganic mercury well in excess of the maximum contaminant level (MCL)maximum contaminant levelThe highest level of a contaminant that EPA allows in drinking water. MCLs ensure that drinking water does not pose either a short-term or long-term health risk. EPA sets MCLs at levels that are economically and technologically feasible. Some states set MCLs which are more strict than EPA's. for many years could experience kidney damage. People concerned about their exposure to inorganic mercury should consult their physician.
- How people are most commonly exposed to other mercury compounds
- Information about inorganic mercury in drinking water
- Technical summary of risk assessment for mercuric chloride in EPA's IRIS database