Occupational Toxicology of Nickel and Nickel Compounds

Nickel and nickel compounds are widely used in industry. The high consumption of nickel products inevitably leads to occupational and environmental pollution. In occupational settings, exposure to nickel and nickel compounds occurs primarily during nickel refining, electroplating, and welding. The most common airborne exposures to nickel in the workplace are to insoluble nickel species, such as metallic nickel, nickel sulfide, and nickel oxides from dusts and fumes. The chemical and physical properties of nickel and nickel compounds strongly influence their bioavailability and toxicity. The lung and the skin are the principal target organs upon occupational exposure. Inhalation exposure is a primary route for nickel-induced toxicity in the workplace. The most important adverse health effects due to occupational exposure to nickel and its compounds are skin allergies, lung fibrosis, and lung cancer. The exact mechanisms of nickel-induced carcinogenesis are not clear. This review summarizes the current knowledge on occupational toxicology of nickel and its compounds. The subtopics include: chemical and physical properties, uses, occupational exposures, occupational exposure limits, toxicokinetics, biological monitoring, acute toxicity, chronic toxicity, genotoxicity, reproductive toxicity, carcinogenicity, molecular mechanisms of carcinogenesis, and gaps in knowledge.