Introduction
Mercury is a natural element present in the soil, water, and air. It exists in organic, inorganic, and metallic forms. Mercury is released into the atmosphere due to human activity, deterioration of rocks (weathering), and volcanic activity. Human activities like coal burning, waste incinerators, industrial processes, and heavy metal mining contribute to the main reason for mercury release. After reaching the environment, bacteria transform mercury into methylmercury and enter living organisms through contaminated water and food. Mercury exposure occurs due to consuming contaminated fish (methyl mercury), industrial processes, and inhaling mercury vapors (industrial workers). Mercury exposure will cause serious health problems and multiorgan failure.
What Is Mercury Poisoning?
Exposure to mercury will cause mercury poisoning. Mercury exists in different forms in the environment. Elemental (metallic) and inorganic mercury exposure will occur due to occupational contact or inhalation during industrial processes. Organic mercury (methyl mercury) exposure occurs through diet. The most common cause is the consumption of contaminated seafood containing methylmercury. Mercury toxicity and its effects depend on the dose, form of mercury, and rate of exposure. Different forms of mercury show variable degrees of toxicity and effects on the skin, eyes, nervous system, lungs, kidneys, digestive system, and immune system. Inhaled mercury primarily affects the brain, and methyl mercury targets body tissues. Mercuric salts will cause damage to the kidney and gut lining. Daily consumption of methyl mercury (organic form) containing fish and shellfish will cause neurological diseases (Minamata disease).
What Are the Causes of Mercury Poisoning?
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Fish - Methylmercury toxicity is mainly caused by eating contaminated seafood, mainly fish. Eating large fish like sharks and swordfish living in contaminated water will cause an increased risk of mercury poisoning. Large fish will contain high amounts of methylmercury because they eat smaller fish that live in the same mercury-contaminated water and also have mercury in their body. Fishes like mackerel, bigeye tuna, and marlin also have a large amount of mercury in their body. Young children, nursing mothers, and pregnant women will develop serious adverse effects after eating contaminated fish. Care must be taken to avoid the use of large quantities of seafood.
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Amalgam Dental Fillings - Dental amalgam contains tin, copper, silver, and zinc combined with mercury. Amalgam exposure from dental treatments can occur during the placement or removal of restorations in the tooth.
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Air - Human activities like coal burning, incineration processes, and industrial air pollution will result in the emission of mercury vapors into the atmosphere and toxicity.
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Mercury Thermometer - When a mercury-containing thermometer is broken, mercury vapors are released into the air and cause toxicity.
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Mining - Mercury is used as an agent for gold mining. It is used to extract minute pieces of gold mixed with soil.
What Are the Symptoms of Mercury Poisoning?
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Skin - Mercury poisoning will cause itching, burning sensation, discoloration, and peeling of the skin.
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Nervous System - Mercury poisoning will cause memory loss, motor skill damage, slow reflexes, low intelligent quotient, paralysis, and numbness.
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Cardiovascular System - Increased mercury levels in the body will cause free radical accumulation and cell death. It results in coronary artery disease and heart attack.
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Respiratory System - Inhaled mercury vapors will cause breathing difficulties. Acute mercury exposure can cause chemical pneumonitis. After a few hours of exposure, chest pain, dyspnea, and dry cough will develop, usually associated with chills, fever, and headache, and sometimes progress to pulmonary edema, respiratory failure, and death.
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Gastrointestinal System - Acute exposure and inhalation of large amounts of mercury vapors are associated with increased salivation, metallic taste, nausea, abdominal cramps, diarrhea, and dysphagia.
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Reproductive System - Mercury toxicity will cause a reduction in sperm count and fertility.
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Renal System - Acute inhalation of mercury vapor will cause nephrotic syndrome, proteinuria, acute tubular necrosis, temporary tubular dysfunction, and oliguric renal failure.
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Muscular System - Mercury poisoning will affect muscular function and cause muscle weakness, lack of coordination, and trouble walking.
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Pregnancy - Mercury poisoning during pregnancy will cause developmental deformity of the fetus. Mercury vapors cable cross the placental and blood-brain barriers and cause birth defects. It also causes abnormal growth and size of the baby. Mercury exposure in lactating mothers can affect the baby as it is also excreted in breast milk.
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Child Development - Exposure to mercury at a young age will cause developmental disturbances. It consists of difficulty speaking and understanding language, impaired motor skills, and reduced hand-eye coordination. Affected children may have red lips, cheeks, and nose, loss of teeth, hair, and nail,
How Can We Diagnose Mercury Poisoning?
Diagnosis of mercury poisoning can be achieved by using several tools. Detailed physical examination, history of exposure, and blood and urine tests can be used. An excessive amount of mercury in a person's body can be detected by blood or urine sample tests. The presence of methylmercury, metallic and inorganic forms of mercury can be detected by blood tests. These forms of mercury readily move into organs like kidneys and the brain, and the original concentration will become half every three days. Blood testing must be done as soon as possible after suspected exposure to rule out toxicity. Urine samples can only detect the presence of metallic and inorganic mercury, not methyl mercury.
How to Treat Mercury Poisoning?
There is no specific antidote or cure for mercury poisoning. Identifying the source of exposure and removing it is the first thing to do. Mercury toxicity is related to the workplace (industries) and environmental exposure. Decontamination after acute exposure can be done by washing the skin with water and soap, removal of clothes, and flushing the eyes using saline. Acute mercury poisoning can be treated with chelation therapy. Chelating agents are drugs used to remove toxic metals from our bodies.
D-penicillamine and Dimercaprol (BAL) are the common chelating agents used for mercury poisoning. Among these, 2,3-dimercapto-1-propane sulfonic acid (DMSA) is approved by the food and drug administration (FDA) for treating mercury toxicity.
Conclusion
Exposure to mercury will result in mercury poisoning. The majority of mercury toxicity occurs due to the consumption of contaminated fish and industrial exposure. Mercury is heavily toxic to the human body. This exposure to this toxic metal will result in multiorgan damage and developmental neurological disorders. Mercury exposure levels in industrial workers must be closely monitored and reduced to prevent toxicity. To avoid birth defects, consuming large fish containing mercury must be avoided during pregnancy.
