Ecotoxicidade do inseticida Fipronil em animais aquáticos

Abstract

Fipronil (FIP) is a second-generation, broad-spectrum insecticide widely used in agriculture and veterinary products. Despite its extensive application, the mechanisms of action and adverse effects of commercial formulations containing FIP as the active ingredient on aquatic organisms are still not fully understood. In this context, the present study aimed to evaluate the potential ecotoxicological effects of a commercial FIP-based formulation (Topline® Pour On) on the development of zebrafish (Danio rerio) and the Mediterranean mussel (Mytilus galloprovincialis) through the assessment of multiple biomarkers. Initially, a literature review on the effects of FIP on aquatic animals was conducted. Subsequently, zebrafish embryos and larvae were exposed to formulation concentrations of 5–100 μg L⁻¹ for 7 days, whereas adult M. galloprovincialis were exposed to 10 μg L⁻¹ for 28 days. The ecotoxicity of FIP in zebrafish was assessed in terms of mortality, hatching rate, neurotoxicity (spontaneous contraction frequency), cardiotoxicity (heart rate), morphological alterations, biometric parameters, and cartilage and bone abnormalities. The effects of FIP on mussels were evaluated through mortality, antioxidant enzyme activity (superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase - GPx), neurotoxicity (acetylcholinesterase - AChE), and oxidative damage (malondialdehyde - MDA). The review findings demonstrated that FIP can cause mortality in aquatic invertebrates and vertebrates, oxidative stress and damage, neurotoxicity, and teratogenic effects, even at environmentally relevant concentrations. The toxicity assays indicated that the FIP-based formulation induced high mortality, reduced hatching rates, neurotoxicity, cardiotoxicity, and morphological, biometric, and skeletal abnormalities in zebrafish. In marine mussels, the formulation did not induce mortality but caused organ-specific alterations in antioxidant enzyme activity (reduced SOD and CAT activity), oxidative damage (increased MDA levels), and neurotoxicity (increased AChE activity) in the digestive gland of FIP-exposed mussels. However, no significant effects on biochemical biomarkers were observed in the gills, confirming the organ-specific nature of the response. This study highlights the importance of investigating the effects of FIP and its commercial formulations on different aquatic species and indicates their potential ecotoxicological impact on both aquatic vertebrates and invertebrates.