Toxicological effects of the emerging contaminant ivermectin on Physalaemus santafecinus larvae

Abstract

Ivermectin (IVM) is an antiparasitic extensively employed in cattle breeding for decades. It can reach aquatic ecosystems and produce negative effects on non-target organisms. So, the aim was to evaluate the effects on survival and behaviour of a commercial formulation of IVM on Physalaemus santafecinus larvae. Behavioural parameters were assessed at 72 h and 96 h. The 96h-LC50 was 3.48 µg/L decreasing significantly to 0.74 µg/L at 120 h. The Risk Quotient for IVM was 167.56 at 120 h, which indicates the high environmental risk. At 72 h of exposure, only the 100 µg/L IVM concentration produced alterations on the behavioural parameters such as swim speed and distance, and the exploration and mobility rate, while at 96 h, even the lowest concentration (1 µg/L) altered some parameters. The lethal and behavioural effects were time dependent. Ivermectin was highly toxic to P. santafecinus larvae, causing alterations on their behaviour at acute exposure times and lethality at environmentally relevant concentrations.