Assessment of risk by biological monitoring.

Variability between workers is reflected in differences in uptake, metabolism, and excretion of toxic substances, and thus individual response to toxic hazards. It is argued that biological monitoring takes account of these differences enabling individual risk assessments to be made. Risk, however, must be seen in terms of clinical and pathological changes-that is, estimated from morbidity and mortality rates-and so laboratory measurements need to be linked to epidemiological studies before they can be used to indicate acceptable or unacceptable uptake of toxic materials.