Biologic criteria for exposures to lead and cadmium.

This study aims to establish a dose-response relationship in exposures to lead and cadmium. For lead, lead concentrations in blood and urine were used as indices of dose. Delta-ALA and coproporphyrin in urine were used as re-sponses. Policemen who were exposed to 0.5-1.0 μg/m3 as well as lead workers exposed to about 30 μg/m3 during working hours were subjects for the study. It was concluded that in a work environment in which workers are exposed to about 30 μg/m3 lead, blood lead concentration increased to above normal level without increase of delta amino-levulinic acid (ALA) in urine. Increase of delta-ALA in urine was noted when the blood lead concentration level exceeded 50 μg/100 ml. For cadmium, both blood and urinary concentrations of cadmium and protein in urine were used in order to discuss the dose-response relation-ship. The relationship between cadmium concentration in blood and in urine was one of logarithmic regression. Among workers exposed to cadmium fume, protein in urine increased when cadmium in urine exceeded 50 μg/l and cad-mium in blood exceeded 4-6 μg/100 ml.