CONICET | Buscador de Institutos y Recursos Humanos

The increasing landscape alterations due to anthropogenic activities is of global concern since it afects aquatic ecosystems,often resulting in compromise of the ecological integrity and the water quality. In this sense, the evaluation, monitoring, andprediction of the aquatic ecosystem quality becomes an important research subject. This study presents the frst integratedwater quality assessment of the Sauce Grande River Basin, in Argentina, based on the spatial distribution of the phytoplanktoncommunity, the physicochemical parameters, and the metal concentrations (Cd, Cu, Cr, Fe, Mn, Ni, Pb, and Zn) found in theparticulate fraction. According to the trophic indices and the phytoplankton abundance, composition, and diversity, the waterquality showed signifcant deterioration in the lower basin after the Sauce Grande lake. The trophic state index indicatedthat water was oligotrophic in over 75% of the sampling sites, increasing downstream, where two sites were characterizedas mesotrophic, and one described as hypertrophic. The phytoplankton community was dominated by diatoms in zones withlow anthropogenic impact and conductivity, whereas high densities of Euglenophyta, Chlorophyta, and Cyanobacteria werefound in the middle-lower basin, associated with higher organic matter and eutrophication. The conductivity, turbidity, andmost metal concentrations also increased towards the downstream area, even exceeding recommended levels for the metalsCu, Cr, Mn, and Pb in the middle and lower reaches of the basin (Cu: 3.5 µg L−1; Cr: 2.4 µg L−1; Pb: 1.2 µg L−1; Mn 170 µgL−1). This study generates a database for the water quality of the Sauce Grande River Basin and sets an example of how thewater quality varies along a basin that crosses diferent topographic environments, land covers, and anthropogenic infuences