Elemental mercury is usually harmless if touched or swallowed. It is so thick and slippery that it usually falls off your skin or out of your stomach without being absorbed.
Considerable damage can occur, however, if mercury is made airborne into small droplets and breathed into the lungs. This can often occur by mistake when people try to vacuum up mercury that has spilled onto the ground.
Breathing in elemental mercury will cause symptoms right away (acute) if enough mercury is breathed in. Symptoms will also occur over time (chronic) if little amounts are inhaled every day. If this occurs, symptoms may include:
Depending on how much mercury is inhaled, permanent lung damage and death may occur. You may also have some long-term brain damage from inhaled elemental mercury.
Unlike elemental mercury, inorganic mercury is usually poisonous when swallowed. Depending on the how much is swallowed, symptoms may include:
- Burning in the stomach and throat
- Bloody diarrhea and vomiting
If inorganic mercury enters your bloodstream, it can attack the kidneys and brain. Permanent kidney damage and failure may occur. A large overdose may cause massive blood and fluid loss from diarrhea and kidney failure, leading to death.
Organic mercury can cause sickness if breathed in, eaten, or placed on the skin for long periods of time. Usually organic mercury causes problems over years or decades, not immediately. In other words, being exposed to small amounts of organic mercury every day for years will likely cause symptoms to appear later. Regardless, a single large exposure can also cause problems.
Long-term exposure will likely cause neurological symptoms, including:
- Numbness or pain in certain parts of your skin
- Uncontrollable shaking or tremor
- Inability to walk well
- Blindness and double vision
- Memory problems
- Seizures and death (with large exposures)
Medical evidence suggests that being exposed to large amounts of the organic mercury called methylmercury while pregnant can permanently damage the baby's developing brain. Most doctors will recommend eating less fish, especially swordfish, while pregnant. These recommendations are made to be extremely cautious. Small exposures are unlikely to cause any problems. Women should talk to their doctor about what they should and should not eat while pregnant.