Comparative study of effect of inorganic lead and cadmium on blood δ aminolevulinate dehydratase in man

Abstract

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.