Abstract

Lauwerys, R. R., Buchet, J.-P., and Roels, H. A. (1973).British Journal of Industrial Medicine,30, 359-364. Comparative study of effect of inorganic lead and cadmium on blood δ-aminolevulinate dehydratase in man. δ-Aminolevulinate dehydratase (ALA¹-D) of red blood cells, lead concentration in blood (Pb-B) and in urine (Pb-U), cadmium concentration in blood (Cd-B) and in urine (Cd-U), and ALA in urine (ALA-U) were measured in 77 workers occupationally exposed to cadmium, and in 73 control workers.

An excellent negative correlation was found between log ALA-D and Pb-B (r = - 0·660) or Pb-U (r = - 0·501), but no significant correlation was found between Cd-B and log ALA-D activity.

Unlike ALA-D, ALA-U is not correlated with Pb and Pb-U in the `normal' range of Pb concentration investigated. Mean ALA-D activity in smokers is lower than in nonsmokers, and this is probably related to the fact that a higher mean Pb-B concentration is found in smokers than in nonsmokers.

It is clear from this investigation that in the general population, and even in Cd-exposed workers, Cd has no significant effect on ALA-D. Moreover, all the available evidence indicates that ALA-D activity of erythrocytes is a very sensitive and specific parameter of lead in blood.