What Are the Hazards of Mercury Exposure?

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Hidden Home Risks Image Gallery Mercury is a neurotoxin which can have devastating consequences, but it is not very common. Check out more images of hidden home risks.

Mercury is not a substance to be taken lightly, as thermometers advise us, pregnancy diets offer ways around it, and the government has regulations about workplace exposure to it.

In its purest form, mercury is a metallic element which is liquid at room temperature and is naturally occurring. It is a silvery substance with atomic number 80 and symbol Hg on the periodic table. The amount of mercury emissions from natural activities, such as volcanic eruptions and the erosion of rocks, is estimated to be around 2,100 tons annually [source: UDEQ].

Human activities are believed to contribute more mercury into the atmosphere than natural ones, possibly 2,900 tons each year [source: UDEQ]. This mercury can come from mining and processing for use in products like thermometers, manufacturing, or energy-related sources like coal-fired power plants.

Mercury is a neurotoxin that has negative effects on the nervous system, leading to brain damage and physical and emotional disorders. Therefore, its presence, either natural or anthropogenic, is a potential issue for humans. The degree of the problem is dependent upon the form of mercury, the amount present, and the individuals exposed to it.

Although exposure to mercury and its compounds can be devastating, it is not an everyday occurrence. In this article, we will explore where mercury is found, how exposure typically occurs, and the consequences that can arise. We will also discuss the precautions people can take to minimize their risk of coming into contact with the substance.

The risks associated with mercury exposure differ significantly among the general population, with one segment experiencing much greater side effects than any other.




Concerns About Safety with Mercury Exposure

USGS scientists use electrofishing to collect fish in Lookout Creek near the Blue River in Oregon. The mercury content of the fish they capture is analyzed.
Photo courtesy of USGS.gov

Not all mercury exposures are the same, and the way mercury enters a person’s system can make a significant difference.

Mercury vapor, whether from industrial exhaust or spills or a broken thermometer, can be extremely damaging to anyone. It is the most hazardous form since it is absorbed through the lungs, allowing much of it to reach the brain. Ingesting small quantities of mercury, on the other hand, may have little or no effect on adults.

That is how most people are exposed to mercury: through ingestion. Exposure is almost always through fish that have been contaminated with methylmercury, a form of mercury generated in the bodies of small sea creatures that have ingested the elemental form, deposited in bodies of water when rain or snow carry it down from the atmosphere or across land in contaminated runoff.

As those small organisms are consumed by larger fish, and those fish are consumed by larger fish and so on, the methylmercury moves up the food chain. Finally, it reaches seafood-eating humans. Most humans have some mercury in their bodies, but few experience such high exposure that they suffer from side effects.

Mercury poisoning is a greater risk for young children and fetuses than for adults. It is important to avoid consuming fish with high levels of mercury, such as tile fish, swordfish, and king mackerel, during pregnancy as even small amounts can harm a developing baby’s brain. A study by the U.S. Environmental Protection Agency found that 8 percent of women of child-bearing age could have unsafe levels of mercury in their blood. The effects of mercury poisoning include cognitive and behavioral disabilities, memory problems, and death at high doses. To reduce the risk of harm, it is important to be aware of where the greatest danger lies. The most common route of exposure is through seafood, particularly large and old fish that have eaten smaller, contaminated fish. The fish to be most wary of include king mackerel, shark, swordfish, and tile fish. Mid-range methylmercury fish, such as chilean sea bass, grouper, marlin, orange roughy, and tuna, should be limited to two or three servings per week. The safest fish and shellfish to eat freely include crawfish, oysters, salmon, sardines, scallops, and shrimp. Pregnant women should avoid the highest-mercury fish altogether but still consume fish for the omega-3s, which are essential for a developing baby. Other ways to reduce the risk of mercury poisoning include avoiding vacuuming up mercury, asking your dentist about fillings, avoiding religious rituals involving mercury, and staying away from mercury-filled glass pendants.

To learn more about mercury poisoning and related topics, check out the links on the following page.


If you have been exposed to mercury and are experiencing any of the following symptoms, seek medical attention immediately:

  • Decreased peripheral vision and/or hearing
  • Impaired speech
  • Muscle weakness
  • “Pins and needles” sensation
  • Reduced motor coordination

[source: EPA]

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Additional Information

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  • Global Mercury Budget. Utah Department of Environmental Quality. http://www.mercury.utah.gov/global_mercury_budget.htm
  • Mercury Background. Agency for Toxic Substances and Disease Registry. http://www.atsdr.cdc.gov/mercury/background.html
  • Mercury: Human Exposure. U.S. Environmental Protection Agency. http://www.epa.gov/mercury/exposure.htm
  • Mercury: Health Effects. U.S. Environmental Protection Agency. http://www.epa.gov/mercury/effects.htm
  • ToxFAQs. Agency for Toxic Substances and Disease Registry. http://www.atsdr.cdc.gov/tfacts46.html
  • A Warning About Continuing Patterns of Metallic Mercury Exposure. ATSDR. http://www.atsdr.cdc.gov/alerts/970626.html


1. What is mercury and how are we exposed to it?

Mercury is a naturally occurring element that can be found in various forms such as metallic, organic, and inorganic. We are exposed to mercury through various sources such as contaminated fish and seafood, dental amalgams, and industrial emissions. Exposure to mercury can have serious health consequences.

2. What are the health effects of mercury exposure?

Mercury exposure can cause a range of health effects such as neurological disorders, kidney damage, respiratory failure, and even death. It can also harm the developing fetus in pregnant women, leading to developmental delays and cognitive impairment.

3. How can we reduce our exposure to mercury?

We can reduce our exposure to mercury by limiting our consumption of certain types of fish and seafood, choosing mercury-free dental fillings, and using alternative products that do not contain mercury. It is also important to properly dispose of any products that contain mercury to prevent environmental contamination.

4. What are the occupational risks of mercury exposure?

Workers in industries such as mining, dental work, and manufacturing are at an increased risk of mercury exposure. They may be exposed to mercury through inhalation or skin contact and may experience symptoms such as tremors, memory loss, and mood swings. Employers should provide appropriate protective equipment and training to minimize the risk of exposure.

5. Can mercury exposure be treated?

There is no cure for mercury poisoning, but the symptoms can be managed through chelation therapy. Chelation therapy involves administering medication that binds to the mercury in the body and helps to remove it. However, prevention is the best approach to avoid the serious consequences of mercury exposure.

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