Avoidance behavior of Eisenia fetida in oxytetracycline- and heavy metal-contaminated soils.

Abstract To determine the behavior of oxytetracycline (OTC) and heavy metals in soil, this study assessed the pollutant-induced avoidance behavior of earthworms ( E. fetida ) exposed to zinc (Zn 2+ ), lead (Pb 2+ ), and OTC in soil. The results showed a clear avoidance response within 48 h of exposure to the highest concentrations of pollutants. Moreover, E. fetida was shown to be more sensitive to Zn 2+ than to Pb 2+ and OTC. Compared with OTC alone, the net response of earthworms increased in the OTC-Zn 2+ and OTC-Pb 2+ combined treatments, indicating a synergistic effect. Moreover, the net response (NR) of the earthworms was higher for OTC-Zn 2+ than it was for OTC-Pb 2+ , possibly reflecting the differences in essential characteristics of Zn and Pb.