Mercury is a naturally occurring element found throughout the Earth’s crust, present in air, water, and soil. While it exists naturally, human activities like coal burning and industrial processes significantly contribute to its release into the environment. Excessive exposure to this heavy metal can pose serious health concerns.
Forms and Exposure Pathways
Mercury exists in several forms. Elemental mercury is found in older thermometers, fluorescent light bulbs, and dental amalgam fillings. Exposure primarily occurs through inhaling its vapor, released from spills or when products containing it break. While dental amalgam fillings are largely considered safe, they can release small amounts of mercury vapor.
Inorganic mercury compounds form when elemental mercury combines with other elements. These compounds are present in the environment from natural mineral deposits and human activities like coal burning and industrial processes. Exposure typically occurs through ingestion from contaminated water or certain traditional remedies, or through dermal contact from some skin-lightening products. Occupational settings also present routes for inorganic mercury exposure.
The most common form of mercury exposure is organic mercury, predominantly methylmercury. Microorganisms in aquatic environments convert inorganic mercury into this form. Methylmercury then enters the food chain, accumulating in fish and shellfish. As larger fish consume smaller ones, methylmercury concentrations increase, making contaminated seafood the primary dietary source of exposure.
Signs of Mercury Overload
Mercury overload manifests through a range of signs affecting various body systems. Neurological effects are common, including tremors, often noticeable as uncontrollable shaking. Individuals may experience numbness or tingling, especially in the hands, feet, or around the mouth, alongside issues with coordination, an unsteady gait, and general muscle weakness.
Cognitive and emotional changes include memory issues, difficulty concentrating, and mental deterioration. Mood swings, irritability, anxiety, and insomnia are also reported. Visual disturbances, hearing difficulties, and impaired speech can indicate mercury’s impact on sensory and motor functions.
Beyond the nervous system, mercury can affect the digestive tract, leading to symptoms like nausea, vomiting, abdominal pain, and diarrhea. A metallic taste in the mouth, excessive salivation, and difficulty swallowing are also possible. The kidneys are another target organ, with potential damage ranging from protein in the urine to kidney failure.
Inhaling elemental mercury vapor can lead to respiratory issues, including cough, shortness of breath, chest pain, and lung inflammation. Skin manifestations such as rashes and discoloration can also occur. In children, mercury exposure is associated with acrodynia, characterized by red cheeks, palms, and soles, peeling skin, and sometimes hair, teeth, and nail loss.
Developing fetuses and young children are especially vulnerable to mercury’s effects, particularly from methylmercury exposure. Mercury can impair the developing brain and nervous system, even if the mother shows no symptoms. This can result in developmental delays, impacting cognitive thinking, memory, attention, language, and fine motor skills.
Identifying and Addressing Mercury Toxicity
Identifying mercury toxicity begins with a medical history and physical examination to assess potential exposure and symptoms. Laboratory tests confirm mercury presence and levels. Blood tests detect recent exposure, especially to methylmercury. Urine tests are preferred for long-term elemental and inorganic mercury exposure, while hair analysis can show methylmercury levels over several months.
Addressing mercury toxicity involves removing the individual from the source of exposure. Supportive care manages specific symptoms. For severe cases, medical intervention may include chelation therapy, where specialized drugs bind to mercury, facilitating its removal. This therapy, administered under medical supervision, helps reduce the body’s mercury burden but requires careful management due to potential side effects. In extreme situations, dialysis or surgical removal of mercury may be necessary.
Reducing Mercury Exposure
Minimizing mercury exposure involves informed dietary choices and careful handling of mercury-containing products. When consuming fish, select varieties with lower mercury levels, such as salmon, sardines, anchovies, and tilapia. Larger, predatory fish like shark, swordfish, and king mackerel tend to accumulate higher mercury concentrations and should be limited or avoided, especially for pregnant or breastfeeding individuals and young children. Consulting local fish advisories can also provide important guidance.
Proper household management of mercury-containing products is important. Items like old thermometers and fluorescent light bulbs should never be discarded in regular trash or poured down drains. Instead, take these items to designated hazardous waste collection sites or participate in retail recycling programs. If a mercury-containing product breaks, ensure proper ventilation, evacuate the area, and contact professional cleanup services.
Individuals in certain occupations, such as mining or manufacturing, face increased risks of mercury exposure and should adhere to strict workplace safety protocols. While dental amalgam fillings are generally considered safe, specific groups like pregnant women or young children might consider alternatives after discussion with their dentist. Removing intact amalgam fillings is not typically recommended, as it can temporarily increase mercury vapor exposure.