In-vivo determination of lead in the skeleton after occupational exposure to lead

Abstract

ABSTRACT The concentrations of lead in the phalanges and in the blood were determined in 22 subjects who had formerly been exposed to lead in a storage battery plant, which had been closed for seven years. The bone lead concentration was measured in vivo using an ϰ-ray fluorescence technique in which two ⁵⁷Co γ-ray sources were used for generating the characteristic ϰ-rays of lead, which were measured with a Ge(Li) detector. In three subjects the variation of the lead concentration along the fore finger was measured together with the lead concentration in the tibia. The measured lead concentrations in the phalanges were between 20 μg/g (our detection limit) and 118 μg/g. The lead concentration in the phalanges was found to increase with the length of employment, but no simple relation was found between the lead concentrations in the blood and in the phalanges. The decrease in the blood lead concentration after the cessation of exposure was followed in four subjects. Seven years after exposure had ended, the blood lead concentration was found to be more dependent on the daily intake of lead than on the release of lead from the skeleton. These experimental results could be explained by a two-compartment model using exchange rates given in publications. This model has also been used to calculate the blood lead concentration that could be achieved after a sudden release of lead from the skeleton.