ANTIBIOTICS OF ZOOTECHNICAL USE - EFFECTS OF ACUTE HIGH AND LOW-DOSE CONTAMINATION ON DAPHNIA-MAGNA STRAUS

To gather data on the effects of antibiotic pollution in freshwater systems and to determine methodological approaches, aminosidine (A), bacitracin (B), erythromycin (E) and lincomycin (L) were subjected to acute high dose toxicity tests (AHDTT) using Daphnia magna and following the EEC protocol (EEC Commission 84/449, 1984); the lethal effect evaluated at 24, 48 and 72 h determined the sequence of decreasing toxicity to be B > E > A > L. Furthermore, the four antibiotics were tested in acute low dose toxicity tests (ALDTT) using Daphnia magna by studying the alteration of phototactic behaviour. This test showed that L and B depressed phototaxis, while A increased the light induced migration rate. E did not alter the phototactic behaviour.