Effect of ketamine on edaphic fauna: behaviour and reproduction assay with Eisenia fetida

Abstract

The increasing use of ketamine for therapeutic and recreational purposes has increased the environmental concerns. This substance has been detected in treated effluents, due to the inefficiency of treatments applied in wastewater treatment plants. Since part of these effluents can be used as water for reuse in agricultural practices, it is important to understand the effects of ketamine on edaphic organisms such as earthworms, which is the objective of the present work. Various concentrations of ketamine (0, 25, 250 and 2500 µg/kg) were tested and the effects evaluate by avoidance and reproduction tests, using Eisenia fetida as a biological model, considered the avoidance behaviour and reproduction as endpoints, according to ISO and OECD guidelines. The results indicated no significant differences (p>0.05) between the concentrations studied. On average, ketamine promoted an escape and a decrease in the number of juveniles in the order of 11% and 26%, respectively, compared to the control treatment. These results seem to indicate no negative effects of the studied concentrations on behaviour and reproduction of earthworms. More studies are needed, with higher concentrations than those applied in the present work in order to define risk levels in edaphic environment.