Carcinogenicity and mutagenicity of nickel and nickel compounds.

A brief description of present concepts of tumour development and the most common genotoxicity tests is given. Data on the mutagenicity testing of nickel are summarized. They indicate that carcinogenic nickel compounds may bring about initiation by means of mutation, such as chromosome breakage and irregular distribution of genetic material. Compared with many mutagenic organic compounds, the efficacy of the nickel compounds is low. Extrapolation to man calls for great caution, since mutation tests involve short-term exposures, while the human situation is characterized by long-term exposure and very long cancer latency periods. The predictive value of mutagenicity tests in evaluating new environmental situations involving nickel compounds is limited. Positive findings identify a carcinogenic hazard, whereas negative findings do not exclude such a hazard. Experimental studies of transformation suggest that nickel compounds may also have promoting properties.