Poisoning from methylmercury causes symptoms such as peripheral vision impairment, physical discomfort, muscle weakness and lack of coordination, speech and hearing impairment, and difficulty walking, warns MedicineNet. Inhalation of elemental mercury vapor can cause tremors, twitching, weakness, muscle atrophy or cognitive decline. High exposure to elemental mercury can cause kidney damage, respiratory failure or death.
Mercury is present in fish and some products people use at home, school or the dentist, according to MedicineNet. Human exposure to methylmercury, an extremely toxic form of mercury, is usually the result of fish or shellfish in the diet. Mercury levels build up over time and may eventually cause mercury poisoning in a person with a large amount of exposure. High levels in the bloodstream of an unborn baby or young child can harm the nervous system, affecting the child's thinking capacity and ability to learn. Health effects of mercury exposure in adults varies depending on the type of mercury, the length of exposure, the route through which the mercury entered the body, and the general health of the person exposed.
A person who is concerned about exposure to mercury and potential poisoning should seek medical advice, states MedicineNet. The Environmental Protection Agency encourages people to use products with mercury alternatives to limit their exposure. It also recommends recycling unused mercury products to reduce environmental exposure.