The effects of arsenic exposure on the nervous system.

Arsenic (As) is a common environmental contaminant widely distributed around the world. Human exposure to this metalloid comes from well water and contaminated soil, from fish and other sea organisms rich in methylated arsenic species, and from occupational exposure. It has been reported that human arsenic exposure causes several health problems such as cancer, liver damage, dermatosis, and nervous system disturbances such as polyneuropathy, EEG abnormalities and, in extreme cases, hallucinations, disorientation and agitation. Although there is evidence that arsenic exposure has a toxic effect on the nervous system there are few studies that address this issue. The purpose of this review is to describe what is presently known about the effects of arsenic compounds on the nervous system in humans and rodents and to discuss its possible mechanisms of action.