Mercury is a naturally occurring compound that's present in water, air and soil. Mercury exists in three forms: metallic (elemental), organic (ethylmercury) and inorganic. Environmental microorganisms are able to convert inorganic mercury to methylmercury, the form of mercury found in some types of fish. Methylmercury is the form of mercury most likely to lead to symptoms of poisoning in humans.
Impaired Neurological Development
Women who are pregnant are often advised to avoid eating fish. Though the small levels of mercury found in some types of fish are generally nontoxic to adults, these small levels can be toxic to the developing fetus as well as infants and children. If an infant is exposed to mercury during development, the normal formation of his brain and central nervous system may be altered. These infants may develop language, memory or attention problems as children. Difficulties with fine motor skills and cognitive thinking have also been reported in children exposed to mercury during fetal development.
Impaired Cognitive Function
If you experience mercury poisoning, you may notice a decline in your normal cognitive function. You may develop difficulty hearing, speaking or walking. Normal tasks, such as washing your hands or walking up a flight of stairs, may become problematic due to decreased coordination and fine motor skills.
Impaired Vision
Mercury poisoning may cause visual impairment in certain people. Impaired peripheral vision, double vision or blindness may develop due to the toxic effect of mercury on the central nervous system.
Skin Sensations
The U.S. Environmental Protection Agency (EPA) explains that mercury poisoning may lead to disturbances in sensations. Such disturbances may include numbness, prickling or pain sensations within the feet, hands or around the mouth.
Upset Stomach
High levels of mercury consumption may cause severe stomach upset in some people. Nausea, vomiting or a burning sensation within the throat or stomach may occur if you've been exposed to poisonous levels of mercury. Some people may observe exhibit bloody vomiting or diarrhea.
Metallic Taste
Excessive mercury exposure may cause a metallic taste. Certain people may develop swelling around the gum, which may cause slight bleeding.
Seizures or Death
In severe cases of mercury poisoning, your body may shake uncontrollably. Mercury poisoning may also cause certain people to develop seizures--a medical condition caused by uncontrolled electrical signaling within the brain--which may cause fainting or loss of consciousness. Exposure to large amounts of mercury may be fatal.
