Morphological Responses and Accumulation of the Emerging Contaminant Ivermectin in Salvinia minima

Abstract

Ivermectin (IVM) is a macrocyclic lactone widely used to control endo- and ectoparasites in livestock. After administration, it is only partially metabolized by the animal and therefore excreted in its original form. IVM can enter water bodies through groundwater, runoff, soil erosion, and direct deposition. Once in aquatic and wetland environments, due to its chemical characteristics, it can persist for a long time, increasing its environmental risk. Macrophytes are in frequent contact with this drug, resulting in chronic exposure and leading to an accumulation process. The objective of this study is to evaluate the uptake of IVM in S. minima, and its phytotoxicity potential. Bioassays were performed by exposing S. minima to different concentrations of IVM, 5 mg/L, 10 mg/L, and 30 mg/L. After 10 days, the accumulation of the compound in fronds, roots, and effluent was measured. Morphological parameters and photosynthetic pigments were evaluated. IVM was found in fronds and roots of S. minima after exposure. The percentage removal of the drug in effluent was significant, up to 66%. Only the highest concentration evaluated caused phytotoxic effects. S. minima proved to be a promising species for IVM removal processes, especially in wetlands subject to intensive livestock farming activities. Of interest is its applicability in wetlands subjected to intensive livestock farming.