Medically reviewed by Neka Miller, PhD on January 21, 2021. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
Heavy metals exist all around us. They occur naturally in the environment, including soil, food, and countless everyday products. Some of these metals are actually necessary to your health, while others would show up as red flags on a heavy metal toxicity test in high enough concentrations.
Mercury is a heavy metal that does not serve any sort of function in your bodily health or well-being. It is a toxic substance, and mercury toxicity can develop if there’s too much of it in the body—contributing to some severe health effects. So how do you get mercury poisoning? Read on to learn more.
A naturally-occurring chemical element, mercury is a heavy metal that can be found in small amounts in soil, sediment, and water. It can eventually find its way into the animals, vegetables, and fruits that you eat, along with a whole host of everyday products.
Mercury occurs in three general forms: elemental (metallic) mercury, inorganic mercury compounds, and methylmercury and other organic compounds.
Elemental mercury, also known as metallic mercury, is a silvery-white, odorless liquid when it’s at room temperature. The metal is most often known as the liquid found in thermometers, but it is also used in fluorescent light bulbs, certain dental fillings, and various industrial processes. The burning of fossil fuels also releases some elemental mercury into the air.
Inorganic mercury compounds take shape when combined with sulfur, oxygen, and other elements, forming into inorganic salts. These can occur naturally, and they are often used in industrial processes and as a tool to create other chemicals.
Methylmercury and other organic compounds form when mercury combines with carbon. This can potentially come from waste from industrial plants. But more commonly, microscopic organisms in certain environments convert elemental and inorganic mercury found in soil and water into the mercury compound methylmercury. This can accumulate in the food chain, particularly in certain large fish. Other organic mercury compounds include phenylmercuric acetate and thimerosal, which are used in small concentrations to make some preservatives.
You can generally get exposed to small concentrations of mercury in your everyday life. These small concentrations shouldn’t have a noticeable effect on your health, but mercury can accumulate in your body under certain conditions, potentially leading to long-term (or chronic) exposure.
While it is possible to accidentally ingest elemental mercury, exposure to this form of mercury usually occurs from breathing in its vapors. When elemental mercury is exposed to air and begins to evaporate, it becomes an invisible, odorless gas that can be toxic when breathed in. This becomes even more of a concern in warm, poorly ventilated indoor spaces. Breathing in the vapor is often more dangerous than ingesting elemental mercury.
Inhalation exposure to elemental mercury vapors can come from broken thermometers or potentially in dental offices that frequently use “silver fillings,” which contain mercury and a mix of other metals. Note that use of mercury-containing fillings is rapidly falling out of favor in dentistry, with safer options now available.
Exposure to inorganic mercury usually comes from working in industrial environments that commonly use inorganic mercury. Some cosmetic products, like skin lighteners and anti-aging creams, contain mercury—but these products usually come from outside the United States and are broadly illegal domestically when it comes to selling the products.
Exposure to methylmercury and other organic mercury is by far the most common cause of mercury poisoning. As mentioned above, organic mercury can make its way into soil and water, eventually ending up in animals we eat, particularly seafood.
Eating some fish or shellfish will not immediately cause huge amounts of mercury to accumulate in your system. However, eating significant quantities of seafood regularly can eventually lead to high levels of methylmercury in your system. This becomes even more likely when you routinely eat fish with a higher mercury concentration in their meat. The fish with the highest levels of mercury include:
Essentially, larger fish with long lifespans are more likely to have a higher mercury concentration.
Exposure to mercury (either chronic or acute) can result in a wide range of different mercury poisoning symptoms that share some similarities with symptoms of arsenic, iodine, or cadmium poisoning. As a neurotoxin, the mercury compound mainly affects your central and peripheral nervous systems. This can have some significant effects on your mood and behavior, including:
Mercury toxicity may also contribute to increased irritability, memory problems, and depression and anxiety disorders.
Along with effects on the nervous system, inhalation exposure to metallic mercury vapors can have harmful effects on the lungs, kidneys, digestive system, and immune system. Inorganic mercury salts are highly corrosive to the skin, eyes, and digestive tract. If ingested, inorganic mercury may also contribute to kidney issues.
Mercury poisoning is also known to have significant effects on fetal and early childhood development. Studies have shown that infants and young children exposed to high concentrations of mercury are known to develop issues later on in life affecting:
Treating mercury poisoning usually involves ending your exposure to mercury. Ceasing your mercury exposure can have a significant improvement on heavy metal poisoning symptoms, but your healthcare provider may also prescribe chelation therapy. This involves the use of a chelating agent, which is a chemical that binds to the mercury in your body and expedites its removal, allowing it to flush out of your system via your waste. Chelation therapy can be administered via oral pills or injection. Other treatment approaches involve the use of dialysis, IV fluids, and/or medication for symptoms.
There are larger, social-based initiatives that can reduce the leak of mercury into the environment. This generally includes:
In your personal life, the best way to prevent mercury poisoning is to watch your diet, especially if you are pregnant as fetuses are more susceptible to the effects of mercury poisoning. While this does not mean having to entirely omit fish and shellfish from your diet, it does mean taking into consideration the amount and type of seafood that you consume.
Eating fish occasionally, even larger species, usually does not introduce enough mercury into your body to pose any serious health issues. However, eating large quantities of fish for most meals or eating mercury-rich fish regularly will naturally increase your mercury levels. Pregnant women and children should generally avoid eating fish known to have higher concentrations of mercury. If you catch your own fish, make sure to check fish advisories in your area.
If your job requires you to be around mercury often, take the proper precautions and wear the necessary safety equipment to prevent exposure.
Heavy metal poisoning symptoms
Cadmium poisoning: causes and symptoms
1. Toxic Substances Portal. Centers for Disease Control and Prevention. URL. Accessed January 21, 2021.
2. Basic Information about Mercury. United States Environmental Protection Agency. URL. Accessed January 21, 2021.
3. How People are Exposed to Mercury. United States Environmental Protection Agency. URL. Accessed January 21, 2021.
4. Health Effects of Exposures to Mercury. United States Environmental Protection Agency. URL. Accessed January 21, 2021.
5. Mercury poisoning. MedlinePlus. URL. Accessed January 21, 2021.
6. Choose Fish and Shellfish Wisely. United States Environmental Protection Agency. URL. Accessed January 21, 2021.