Nickel: A review of its sources and environmental toxicology

Nickel is a metal of widespread distribution in the environment: there are almost 100 minerals of which it is an essential constituent and which have many industrial and commercial uses. Nickel and nickel compounds belong to the classic noxious agents encountered in industry but are also known to affect non-occupationally exposed individuals. The general population may be exposed to nickel in the air, water and food. Inhalation is an important route of occupational exposure to nickel in relation to health risks. Most nickel in the human body originates from drinking water and food; however, the gastrointestinal route is of lesser importance, due to its limited intestinal absorption. The toxicity and carcinogenicity of some nickel compounds (in the nasal cavity, larynx and lungs) in experimental animals, as well as in the occupationally exposed population, are well documented. The objective of this paper is to summarize the current overview of the occurrence and sources of nickel in the environment, and the effect of this metal and its compounds on living organisms. As this topic is very broad, this review is briefly concerned with the toxicokinetics of nickel, its health effects and biological monitoring.