Mercury poisoning is the result of being exposed to too much mercury, either through the diet or environment. Mercury is a heavy metal that is highly toxic to humans.
Consuming food that contains mercury is the most common cause of mercury poisoning. Mercury poisoning can cause severe symptoms and put the body at unnecessary risk.
A person can help prevent mercury poisoning by making changes to their diet and environment that limit exposure to the toxic metal.
Mercury is a naturally occurring metal that is in many everyday products, albeit in tiny amounts. While this limited exposure is usually considered safe, a buildup of mercury is highly dangerous.
Mercury is a liquid at room temperature and readily vaporizes into the air around it. It is often a by-product of industrial processes, such as burning coal for power. Vaporized mercury can make its way into the rain, soil, and water, where it poses a risk to plants, animals, and humans.
Ingesting or coming into contact with too much mercury can cause symptoms of mercury poisoning.
Mercury may affect the nervous system, leading to neurological symptoms such as:
As the levels of mercury in the body rise, more symptoms will appear. These symptoms may vary depending on a person's age and exposure levels. Adults with mercury poisoning may experience symptoms such as:
- muscle weakness
- metallic taste in the mouth
- nausea and vomiting
- lack of motor skills or feeling uncoordinated
- inability to feel in the hands, face, or other areas
- changes in vision, hearing, or speech
- difficulty breathing
- difficulty walking or standing straight
Mercury can also affect a child's early development. Children with mercury poisoning may show symptoms such as:
- impaired motor skills
- problems thinking or problem-solving
- difficulties learning to speak or understanding language
- issues with hand-eye coordination
- being physically unaware of their surroundings
Mercury poisoning tends to develop slowly over time if a person comes into frequent contact with mercury. However, in some cases, mercury poisoning comes on quickly and is associated with a specific incident.
Anyone who experiences a sudden onset of mercury poisoning symptoms should call a doctor or poison control.
Exposure to high levels of mercury may also put a person at risk for long-term complications, including:
High levels of mercury in the blood may put a person at risk for long-term neurological damage. These effects may be more pronounced in children who are still developing.
A study in the Journal of Preventive Medicine and Public Health noted that many incidents of mercury poisoning have led to long-term nerve damage, which can cause:
- intelligence disorders and low IQ
- slow reflexes
- damaged motor skills
- problems with memory and concentration
- symptoms of ADHD
Mercury poisoning also poses a risk to the reproductive system. It may cause reduced sperm count or decreased fertility and may also cause problems with the fetus.
Possible effects of mercury poisoning include deformity and a decreased survival rate of the fetus, and reduced growth and size of the newborn at birth.
Mercury helps promote the accumulation of free radicals in the body, which puts the cells at risk for damage. This may lead to an increased risk of heart problems, including heart attack and coronary heart disease.
The most common cause of mercury poisoning is from eating seafood, but people can get mercury poisoning from industrial processing, thermometers and blood pressure machines, dental work, and old paints.
Mercury poisoning from seafood
Eating seafood that has been tainted with mercury is one of the most common ways humans accumulate mercury in their bodies. The mercury in seafood is a highly poisonous form of the metal called methylmercury, which forms when mercury dissolves into the water.
Methylmercury can be absorbed from the water by all sea creatures, but it also continues through the food chain.
Small sea creatures, such as shrimp, often ingest methylmercury and are then eaten by other fish. These fish will now have more methylmercury in them than the original shrimp.
This process continues all the way up the food chain, so that a large fish may contain much more mercury than the fish it has eaten. This does not necessarily make it better to eat smaller fish, however. It is always essential for a person to check the source of their seafood to avoid contaminated fish and shellfish.
People worried about their exposure to mercury may want to limit their seafood intake, particularly of fish that are high on the food chain, such as swordfish, shark, white tuna, pike, walleye, and bass.
Pregnant or breast-feeding women may want to avoid or restrict their intake of fish and shellfish, as any mercury they contain can pass to the fetus or infant through the umbilical cord or breast milk.
Amalgam fillings, commonly called silver fillings, contain approximately 40 to 50 percent mercury. Amalgam fillings are not often used now, as there are newer and safer alternatives.
Old fillings may increase a person's risk for mercury exposure. Some people choose to replace their amalgam fillings to reduce their long-term exposure to mercury.
Mercury poisoning may also be due to direct or environmental exposure. Mercury exposure may come from one or more of the following sources:
- mining for gold
- exposure to some types of jewelry
- exposure to older paints
- some vaccinations
- contact with a broken fever thermometer or older house thermometer
- toxic air in areas near factories that produce mercury as a by-product, such as coal plants
Some skin care products may also be tainted with mercury, though this is uncommon.
Doctors can usually diagnose mercury poisoning through a physical exam and blood tests. Doctors may ask about any symptoms the person is having, as well as for a general breakdown of their diet.
They may also ask questions about the environment the person lives or works in, including whether they live near any factories or work in an industrial plant.
If the doctor suspects mercury poisoning, a blood and or urine mercury test can gauge the levels of mercury in the body.
Treatment of mercury poisoning involves eliminating any and all exposure to the metal. Doctors will recommend that the person does not consume any seafood that contains mercury.
If mercury poisoning is related to a person's workplace or environmental exposure, doctors may suggest that the person change their environment to reduce their exposure, or that the workplace puts new safety measures in place.
Mercury poisoning may cause some long-term side effects, which will be treated or managed individually.
Certain types of severe cases of mercury poisoning may require chelation therapy. This is the process of removing mercury from the organs so the body can dispose of it.
The drugs used in chelation therapy bind to heavy metals in the bloodstream and are then eliminated in the urine. Chelation therapy comes with its own risks and side effects, so it is crucial to use the medication only when necessary.
Mercury is toxic to humans. There is no standard cure for mercury poisoning, so it is best to avoid exposure to high amounts of mercury when possible.
Eliminating risk factors by making changes in the diet and work or living environment may help reduce the levels of mercury in the body.
It is essential to consult a doctor at the first sign of mercury poisoning, as it can have long-lasting effects. Parents and caregivers should also be aware of the signs of mercury poisoning in children and call a doctor if a child or infant displays any symptoms.