Eighty behavioral measures of task performance and five measures of body burden of lead (7439921) were clinically obtained from 316 experimental and 112 control subjects. The experimental subjects were volunteers from among workers exposed to inorganic lead at their jobs in three storage (lead-acid) battery manufacturing companies. The controls had never been exposed to inorganic lead and matched the experimentals as closely as possible in terms of sex, race, age, education, duration of employment, and similar geographic location. The results obtained with the five measures of body burden indicate that for the experimental subjects the measures were intercorrelated, and each measure could be predicted from each of the other measures; the measures for the control subjects were not all intercorrelated. These data also indicate that blood lead is not a sensitive measure of changes in functional (performance) capacity. Aminolevulinic-acid dehydrase in the blood (blood ALA-D) was found to be the most sensitive predictor of task performance. The relationships among the measures of task performance and body burden of lead were examined through the use of correlation and multiple-regression analyses, analyses of variance and covariance (where appropriate), and a factor analysis. The results of these analyses indicate that the intellectual functions measured in this study were unaffected by increases in body burden of lead. On the other hand, sensory (hearing), neuromuscular or psychomotor (tremor, eye-hand coordination, muscular strength, and endurance), and psychological (hostility, aggression, and general dysphoria) functions were all influenced by body burden of lead. The strongest relationships were obtained with tests of neuromuscular and psychomotor functions; major changes occurred on the preferred side of the body at blood lead levels between 70 and 79 micrograms percent.
National Institute for Occupational Safety and Health, Cincinnati, Ohio, Interim Technical Report No. ITR-74-27, NIOSH Contract No. 099-72-123, 252 pages, 172 references