Genotoxic Potential of the Insecticide Imidacloprid in a Non-Target Organism (<i>Oreochromis niloticus</i>-Pisces)

Abstract

The indiscriminate use of pesticides has become a serious environmental concern. Insecticide imidacloprid (IMI) is the second most widely used pesticides worldwide. In 2010, 1.934 tons of IMI were sold in Brazil, mostly to be used in sugarcane crops. Several studies have detected its presence in the aquatic environment constituting a risk to non-target organisms. The aquatic animals are organisms used for environmental biomonitoring worldwide. They are considered excellent genetic models to detect environmental mutagens. Among animal species, the fish Oreochromis niloticus, commonly known as Nile tilapia, has been used to evaluate DNA damage. The present study therefore evaluated the effect of IMI on the genetic material of Oreochromis niloticus (Pisces) erythrocytes exposed to different concentration (250; 125 and 62.5 μg/L) of IMI used in growing sugarcane. The effect of the IMI was measured using the comet assay and the micronucleus (MN) test, assays that detected genotoxic damage. The results in the comet assay demonstrated that the concentrations tested induced primary damage to DNA. They also proved the occurrence of MN and nuclear abnormalities at the higher concentration used in the micronuclei and other nuclear abnormalities test. The insecticide IMI induced primary DNA damage at all concentrations and damage at the chromosomal level at the highest concentration tested. The results of this study show the potential risk of IMI in a non-target organism.