Mercury
What is mercury?
Mercury is a heavy, silvery-white metal element. It can exist as a liquid at room temperature or as a solid crystal salt. The liquid metal form gives off invisible, odorless, toxic vapors. Commonly, metallic mercury can be found in thermometers, barometers, electrical switches, thermostats and in dental fillings.
You will mainly come into contact with mercury by eating fish and shellfish caught in contaminated waters and metallic mercury spills of small amounts, such as from a broken thermometer. Reduce the majority of your contact with mercury by:
- Following fish consumption advice from the Wisconsin Department of Natural Resources’ (DNR) to reduce eating mercury-contaminated fish.
- Cleaning mercury spills properly. If an item containing mercury breaks in your home or workplace, you may breathe in mercury vapors that are released into the air.
How can I be exposed to mercury?
Mercury in our environment is commonly found in three different forms: elemental mercury, methylmercury, and mercury salts.
Known as metallic mercury, this form of mercury is a heavy, silvery metal element that is a liquid at room temperature. This form is commonly found in the home in thermometers, barometers, electrical switches, and thermostats. Elemental mercury is also sometimes used in religious rituals and was historically used in latex paint to extend its shelf life.
Liquid mercury evaporates at room temperature and these vapors are invisible, odorless, and, at high levels, are very toxic. Even small spills can cause high levels of mercury vapors that are unsafe to breathe. You should respond immediately to all mercury spills.
Known as organic mercury, this mercury is released from industries into the air and can travel long distances and end up in soil and in lakes.
In lakes, small organisms change the mercury to a form of organic mercury (methylmercury) that builds up in the bodies of fish.
Some lakes in Wisconsin have health advisories regarding eating fish that recommend against eating too much of certain types of fish containing high levels of methylmercury.
Inorganic mercury salts are used in fungicides and preservatives for seeds, wood products, fluorescent lights, and in the manufacture of batteries and paper.
Mercury salts are quite corrosive and if eaten, can quickly damage tissues of the digestive tract and kidneys. Inorganic mercury may also be found in some skin lightening creams.
Dental fillings: Some dental fillings contain mercury and blood levels may be elevated for a short time after teeth are filled.
Latex paint: People who work with exterior latex paint containing mercury can absorb mercury through their skin or by breathing in unsafe air in unventilated areas.
Contaminated water: Mercury can enter the body when contaminated water is used for drinking or for preparing food. If a water supply is contaminated, people can absorb mercury as they bathe or use the water for other purposes. The state and federal drinking water standards are both set at 2 ppb of mercury. We suggest you stop drinking water containing more than 2 ppb of mercury. If levels of mercury are very high in your water, you may need to avoid washing, bathing, or using the water for other purposes.
How can mercury affect my health?
All three common forms of mercury in our environment can impact your health. Breathing mercury vapors from a mercury spill is dangerous and can have short-term and long-term health effects.
When elemental mercury, known as metallic mercury, is touched it can slowly pass through the skin. Seek medical advice if you have any symptoms that you think may be related to a chemical exposure.
Short-term, or acute exposure, to mercury typically means you came in contact with the chemical for a small amount of time, usually less than a two-week period.
- Neurological effects, confusion, hand tremors
- Chills
- Chest tightness, bronchitis, pneumonia
- Abdominal pain, nausea, vomiting, and loss of appetite
- Bleeding gums
- Leg pains and burning sensation in feet
- Lung and kidney damage
- Skin rashes
Long-term, or chronic exposure, to mercury typically means you came in contact with the chemical for years.
- Blood in urine
- Shaking
- Burning pain in legs and feet
- Sleep disturbance
- Personality changes
- Irritability
- Memory loss
Who regulates mercury in Wisconsin?
The DNR regulates how much mercury can be released into the air and groundwater in Wisconsin.
DNR regulates the amount of mercury that can be released by industries. Although no standards exist for the amount of mercury allowed in the air of homes, we used a formula to convert workplace limits to suggested home limits. Based on the formula, we recommend levels of mercury to be no higher than 2 parts per billion (ppb) in the air.
DNR also regulates how much mercury can be in water served by public water systems and oversees the clean up of contaminated sites.
Related topics
Our groundwater standards page has information on how Wisconsin's groundwater standards are set, the Department of Health Services' role in the process, and a summary of the current and recommended standards including mercury.
ATSDR's ToxFAQs page and EPA health effects of exposures to mercury page has more information on mercury exposure routes and health effects.
Questions?
Can't find what you're looking for? Email: dhsenvhealth@dhs.wisconsin.gov