Effects of inorganic lead on delta-aminolevulinic acid dehydratase activity and hematological variables in the rainbow trout, Salmo gairdnerii.

The activity of the enzyme delta-aminolevulinic acid dehydratase (ALA-D) was strongly depressed in erythrocytes, spleen and renal tissue of rainbow trouts (Salmo gairdnerii) exposed to sublethal levels of inorganic lead (10, 75 and 300 microgram Pb2+/L) for 30 days. The fish exposed to the highest lead concentration also showed an anemic response and basophilic stippling of erythrocytes. The lead exposure did not cause any alteration of the white blood cell picture. The ALA-D inhibition, the anemia and basophilic stippling seemed to persist in the lead-exposed fish even after a recovery period of seven weeks in lead-free water.