Mercury is toxic to the human nervous system. Chronic breathing of mercury vapors can cause a range of physical symptoms, including inability to coordinate body movement and impairment of hearing, speech and vision. Exposure to mercury in other forms can lead to skin rashes and kidney damage.
Improper recycling or disposal of mercury-containing products or by-products could cause toxic mercury to be released into the environment resulting in neurological damage to unborn children. According to estimates, 85,000 U.S. women of childbearing age in a given year have been exposed to elevated methylmercury levels sufficient to affect the brain development of their babies. (Reported by the National Wildlife Federation).
Ever since the tragic results of mercury poisoning in Minamata Japan in the 1950's, extensive research has been done in the field of mercury toxicity in environmental settings. In general, it has been learned that elemental mercury that is released to the environment can be deposited into lakes, rivers, and the oceans. Here a biological process takes place where the mercury is converted into methylmercury, a highly toxic organic form of mercury. The methylmercury is then consumed by various animals in the food chain where it bioaccumulates. This bioaccumulation causes very small amounts of mercury in lower animals forms to become concentrated in larger animals to levels where their consumption could cause elevated levels of methylmercury in humans.
The most common way for mercury to enter aquatic ecosystems is through vapor deposition. Mercury has a low vapor pressure and consequently whenever it is heated the liquid metal becomes a vapor air pollutant. Mercury is released to the environment anytime mercury-containing wastes are processed in a municipal waste incinerator. In addition, improper fluorescent lamp recycling also causes mercury to be released to the environment.