Mercury poisoning occurs when a person is exposed to mercury in amounts that overwhelm the body’s ability to detoxify and eliminate it. Mercury is a heavy metal that exists in several forms: elemental (metallic) mercury, inorganic mercury compounds, and organic mercury compounds such as methylmercury. Each form has different sources and ways it can enter the body, but all can cause toxic effects when exposure is significant.
The most common cause of mercury poisoning is inhaling mercury vapor. Elemental mercury is liquid at room temperature but evaporates easily into a colorless, odorless vapor. This vapor can be inhaled during activities like handling mercury-containing products, burning fossil fuels, or from dental amalgam fillings that contain about 50% mercury. When inhaled, mercury vapor is absorbed rapidly through the lungs into the bloodstream and can cross into the brain, causing neurological and systemic damage. Symptoms from inhalation include headaches, memory loss, tremors, irritability, insomnia, muscle weakness, and kidney problems. Long-term exposure can lead to severe neurological impairments, emotional instability, and even death.
Another significant cause is ingestion of organic mercury compounds, especially methylmercury, which accumulates in fish and shellfish. Eating contaminated seafood is a major source of mercury poisoning worldwide. Methylmercury is highly toxic because it easily crosses the blood-brain barrier and placenta, affecting the nervous system and developing fetuses. Symptoms include sensory disturbances, coordination problems, vision and hearing impairment, and cognitive deficits.
Inorganic mercury compounds, found in some skin-lightening creams, traditional medicines, and industrial products, can cause poisoning through skin absorption or ingestion. These compounds mainly affect the kidneys and gastrointestinal tract, causing symptoms like abdominal pain, vomiting, and kidney damage.
Occupational exposure is another important cause. Workers in industries such as mining, manufacturing of thermometers, fluorescent lamps, and batteries, or those involved in burning coal and waste incineration, may inhale mercury vapor or come into contact with mercury compounds. Improper handling or disposal of mercury-containing products can also lead to environmental contamination and human exposure.
Dental amalgam fillings have been a controversial source of mercury exposure. These fillings release small amounts of mercury vapor, especially when disturbed during removal or chewing. While the amount released is generally low, improper removal techniques can increase exposure and risk of poisoning.
Mercury poisoning symptoms are diverse and can affect multiple organ systems. Early signs include fatigue, headaches, irritability, and digestive issues. As poisoning progresses, neurological symptoms such as tremors, memory loss, emotional instability, and sensory impairments become more pronounced. Severe poisoning can cause kidney failure, respiratory problems, and death.
In summary, mercury poisoning is caused by exposure to mercury vapor, ingestion of mercury-contaminated food, skin contact with mercury compounds, or occupational hazards. The form of mercury and route of exposure determine the severity and type of symptoms experienced. Preventing mercury poisoning involves minimizing exposure to mercury sources, using safe handling practices, and proper environmental controls.
