Valciukas J A, Lilis R, Fischbein A, Selikoff I J, Eisinger J, Blumberg W E
Science. 1978 Aug 4;201(4354):465-7. doi: 10.1126/science.663669.
Central nervous system dysfunction was investigated in workers at a secondary lead smelter by means of performance tests. Correlations between test scores and zinc protoporphyrin levels, a biological indicator of lead toxicity, are statistically significant. This correlation should prove to be useful in current efforts to evaluate effects of lead exposure.