Biological exposure and/or effect limits, facts, fallacies, and uncertainties: practical aspects.

In the preceding article general principles in setting biological occupational exposure limits (BOEL) and effect limits (BOEEL) were discussed. Here monitoring in every day occupational health practice is discussed. The specific objectives of biological monitoring (BM) and biological effect monitoring (BEM) determine to a large extent the choice of the parameters to be measured. According to the objective, the assessment may be either simple or sophisticated. The choice of an appropriate reference is essential for a valid evaluation of internal exposure, health risk and state of health. The measurement strategy depends on the working mechanism and the kinetics of the chemical. Protocols for BM and BEM-programmes should be regularly updated. Different compounds of the same metal may carry widely different health risks. In general it is necessary to correct the excretion of chemicals for dilution of the urine.