Abstract
Traditionally, air sampling and analyses have been used to determine a worker's exposure to various airborne contaminants. Airborne Threshold Limit Values and permissible exposure levels have been developed for many contaminants. In certain situations, however, measurements of airborne concentrations are not always a reliable index of employee exposure. The determination of a chemical agent or its metabolite in a biological medium such as blood may provide more accurate information on exposure and the effects of exposure to hazardous substances. Perhaps the most common application for biological monitoring has been the determination of lead in blood. Analytical techniques have been developed for an additional parameter, zinc protoporphyrin, which, together with the blood-lead level, can give a more complete picture of lead absorption and metabolism. Information on blood-lead and zinc protoporphyrin monitoring as well as the relationship between the two parameters for a particular industry are discussed.