Abstract

Lead and zinc concentrations in plasma, erythrocytes, and urine, urinary ALA concentration, and ALA-D activity in blood were studied for four hours in two male lead workers during and after a one hour infusion of Ca-EDTA 2Na. Urinary and plasma lead concentrations increased as a result of administering Ca-EDTA 2Na, and the ratios of lead concentrations in plasma to those in urine were greatly increased. The increase of plasma lead concentration was not due to the haemolytic effect of Ca-EDTA 2Na but was mobilised lead, rapidly excreted in the urine. ALA-D activity in blood increased at the end of the experiment with a transient decrease during the infusion of Ca-EDTA 2Na. As zinc concentrations in erythrocytes and plasma did not decrease during the infusion despite an increase in the urinary excretion of zinc, the transient decrease of ALA-D activity was not due to a loss of zinc caused by Ca-EDTA 2Na. From the results of additional experiments in vitro, this transient decrease could be related neither to Ca-EDTA 2Na nor to lead in the blood.