Toxicity Effects and Biomarker Responses in Two South American Freshwater Prawns Exposed to Pesticides

The freshwater crustaceans Macrobrachium borellii and Palaemon argentinus are key components of benthic communities and are widely distributed throughout South American freshwater ecosystems. As native species, they inhabit environments frequently impacted by pollutants from agricultural activity. Due to their marked sensitivity to these chemical stressors, both species have been proposed as valuable bioindicators for monitoring freshwater pollution. The aim of this study was to synthesize available information regarding the effects of several pesticide classes on standard ecotoxicological endpoints. Specifically, the review examines lethal concentration values (e.g., LC50) and sublethal effects including metabolic disorders, histopathological alterations, and behavioral changes used as biomarkers. These biological responses were evaluated across different life stages, including embryos, larvae, and adults. Reports to date show that both species are highly sensitive to pesticides with different mechanisms of toxicity. Such biological responses are significantly influenced by concentration, exposure time, and developmental stage. The information collected on the biological and ecological characteristics of M. borellii and P. argentinus supports their suitability for ecotoxicological research and underscores their role as reliable indicator organisms for assessing the health of South American aquatic ecosystems.