Environmentally relevant concentrations of chlorpyrifos affect behavior and physiological responses of Girardia tigrina

Abstract

Abstract Chlorpyrifos, an organophosphate insecticide widely used to control agricultural pests, poses a significant environmental threat due to its toxicity and persistence in soil and water, causing deleterious effects on non-target organisms. In this context, our work aimed to evaluate the acute (survival) and chronic (regeneration, locomotion and reproduction) toxicity of chlorpyrifos in tropical freshwater planarians Girardia tigrina. The 48h lethal concentration (LC50) of the commercial formulation, containing 480 g L− 1 of chlorpyrifos active ingredient, was determined to be 622.8 µg a.i. L− 1 for planarians. Sublethal effects were also observed, with a significant reduction in locomotion and delayed head regeneration (equal lowest observed effect concentration – LOEC = 3.88 µg a.i. L− 1). Our study highlight the importance of employing physiological and behavioral parameters as effective tools for assessing the ecotoxicological impact of organophosphate insecticides on non-target tropical freshwater organisms, such as G tigrinia. Overall, this study demonstrates the potential of chlorpyrifos-based insecticides to harm natural populations of freshwater planarians at environmentally relevant concentrations. The observed toxicity serves as a cause for concern, emphasizing the need for stricter regulations and careful management of chlorpyrifos usage to mitigate its deleterious effects on aquatic ecosystems. By understanding the specific impacts on non-target organisms like G. tigrina, we can make more informed decisions regarding using and regulating organophosphate insecticides, ultimately promoting sustainable agricultural practices and environmental conservation.