Exposure of man to environmental nickel--an exposure commitment assessment.

Nickel is one of many trace metals that are pervasive in the environment, being released from natural and man-made sources, and to which man is exposed. Representative values of nickel concentrations in the background environment and in man are selected from available data and a pathway analysis is performed to illustrate application of the exposure commitment method to environmental pollutant assessment. Estimated dietary intake of nickel is of the order of 170 micrograms d-1. With fractional absorption of five per cent, retention in the body of 30 per cent of the absorbed amount and an estimated mean body content of nickel of 500 micrograms, an effective mean retention time of 200 days is derived. Contributions to the body burden from drinking water and inhalation of nickel in air are generally less important than dietary intake in normal circumstances. The exposure evaluation is performed for total nickel in the environment and in man. Relationships for specific nickel compounds would be useful and can be derived in a similar fashion as data become available.