Mercury

Water Quality | Mercury

Why are we concerned about Mercury?

Prolonged or chronic exposure to mercury may cause damaging health effects. The adverse health effects are dependent on the form of mercury the individual is exposed to, the dose, and the exposure route. Bacteria containing methylmercury are consumed by the next higher level in the food chain. In addition, the bacteria excrete methylmercury to the water where it can adsorb to plankton, which are then consumed by the next level in the food chain. Animals accumulate methylmercury at a faster rate than they are able to eliminate it, and thus animals consume higher concentrations of mercury at each successive level of the food chain.

Humans are exposed to methylmercury almost exclusively by eating contaminated fish and wildlife at the top of aquatic food chains. Effects of methylmercury toxicity include tingling of the skin, numbness, lack of muscle coordination, tremor, tunnel vision, loss of hearing, slurred speech, skin rashes, abnormal behavior, intellectual impairment, cerebral palsy, coma, and death, depending on the level of exposure. Prenatal exposure to methylmercury, even at levels that do not appear to affect the mother, may effect the development of the central nervous system and may cause psychomotor retardation for affected children. Mild neurological and developmental delays may occur in infants ingesting methylmercury in breast milk. Affected children may exhibit reduced coordination and growth, lower intelligence, poor hearing and verbal development, cerebral palsy, and behavioral problems.

Elemental mercury, the form released from broken thermometers, is less toxic than methylmercury, but still poses health risks. This form of mercury causes tremors, memory loss, headaches gingivitis, excitability, bronchitis, weight loss, fatigue, gastrointestinal problems, thyroid enlargement, unstable pulse, and toxicity to kidneys when vapors are inhaled over a long period of time. If this form is ingested, it is absorbed relatively slowly, and may pass through the body without causing damage. There are also long-term health effects associated with exposure to inorganic mercury, which include kidney toxicity, tremors, loss of coordination, slower physical and mental responses, gastrointestinal problems, and gingivitis.

Although mercury is a very useful element with many unique properties and applications, it poses a very real health risk. This risk can be minimized by reducing the use of mercury-containing products and properly disposing of mercury-containing waste.

For more information about mercury, contact Susy King, our mercury coordinator.