Water Quality Assessment in the Reconquista Basin and Its Effects on a Native Freshwater Gastropod

This study assessed toxicological effects of anthropogenic pollution in Las Catonas stream (Reconquista River basin, Argentina) on the freshwater gastropod Biomphalaria straminea and water physicochemical parameters including Cd, Cu, Pb, Zn and the pesticides chlorpyrifos and glyphosate detection. Water samples were collected (April 2022 and 2023) downstream of industrial treatment facilities and peri urban farms and acute and subchronic bioassays were performed exposing B. straminea snails to the samples. A multibiomarker approach was employed, including biochemical and reproductive responses. Although most physicochemical variables were within guideline values, fluctuations in pH, dissolved oxygen, ammonium and nitrites levels were noted. Metals and pesticides were not above the detection limits (Cu and Zn: 50 μgL¹; Cd and Pb: 0.1 μgL¹; chlorpyrifos and glyphosate: 0.01 μgL¹). Water samples from both sites elicited some variable biological responses, indicating site and year dependent alterations, so longer term and seasonal assessments are required to obtain conclusions more robust. The reduction in hatching success in snails exposed to water samples reinforces the importance of incorporating early life stages of B. straminea into ecotoxicological water assessments.