Comparative study of toxic lead effect on gill and haemoglobin of tilapia fish

This study was designed to determine the 72-h LC50 of lead for tilapia fish (Oreochromis hornorum), as well as the effect of exposure to sublethal lead concentrations (15, 23, 31, 39 and 47% of the LC50) on gill tissue lysosomal membranes of the fish and thaemoglobin concentration in blood. The LC50 value was found to be 202 mg Pb2+ l-1. Exposure to sublethal lead concentrations for 72 h showed significant increases in the lability of gill lysosomal membranes, measured by the release of acid phosphatase. Changes in membrane lability and in haemoglobin concentration were dependent on the amount of lead used during the exposure. We considered that the membrane lability is an adequate parameter to assay for monitoring lead contamination in water, because it is more sensitive than the haemoglobin concentration in blood.