Biological monitoring of occupational exposure to nickel.

Biological monitoring and hygienic monitoring complement each other in assessing occupational exposure to nickel. Biological monitoring is mainly directed to following the exposure of individual workers. In order to estimate exposure from data on biological monitoring, the exposing agent, i.e., the chemical species of nickel involved must be known. Comparisons between exposures are most reliable when made under similar exposure conditions. In particular, when urine is monitored, contamination of the sample from the dust in the air, workers' clothes, and hands, is a major problem. The sampling time must be standardized. At present, no clear-cut preference can be given to plasma rather than urine or vice versa. With the exception of nickel carbonyl poisoning, no health risk estimation can be performed based on the results of biological monitoring. Cytogenetic methods do not seem appropriate for assessing risk or exposure. The increase in chromosome gaps reported in one study seems to indicate the need for further research.