EVALUATION OF ERYTHROCYTE 5-AMINOLEVULINIC ACID DEHYDRATASE ACTIVITY IN THE BLOOD OF CARP CYPRINUS-CARPIO AS AN INDICATOR IN FISH WITH WATER LEAD POLLUTION

The activity of erythrocyte 5-aminolevulinic acid dehydratase (ALA-D) of carp Cyprinus carpio was measured under a variety of lead exposure conditions. A two-week exposure of carp to water lead concentrations of 10-1,000 ppb strongly inhibited their ALA-D activities with increasing water lead concentrations. When carp were exposed to water lead concentration of 100 ppb, depressed activity of ALA-D became visible after only 2 days, and this activity became even less with increasing exposure periods. The ALA-D activity of carp after the fish were transferred from water lead concentration of 200 ppb to lead-free water recovered to only 50% of the value in the control fish even after four weeks. Therefore, these characteristics concerning ALA-D in carp blood indicate that this enzyme is useful as a short-term indicator of lead pollution in the fresh waters of Japan.