Reversibility of psychological performance in subclinical lead absorption.

To evaluate the reversibility of the effect of lead on psychological performance, five performance scale subtests of the Wechsler Adult Intelligence Scale were conducted twice at two-yr intervals on 17 gun-metal foundry workers who had initial blood lead (BPb) concentrations of 30-64 (median 40) micrograms/dl. The results indicated that psychological performance was significantly affected by lead absorption in the first examination, resulting in a reduction in score on picture completion at the BPb level of 40-64 micrograms/dl. In the second examination, following a decrease in the BPb level, the reduced performance recovered. The two-year alteration in the picture completion subtest in all workers was significantly correlated with the corresponding change in mobilization yield of lead in urine by CaEDTA. It is suggested that the effect of lead on psychological performance is reversible at the BPb level below 65 micrograms/dl.