Water quality analysis based on phytoplankton and metal indices: A case study in the Sauce Grande River Basin (Argentina)

This study presents the first integrated water quality assessment of the Sauce Grande River Basin. This South American freshwater environment contains two water bodies that interrupt its course before the river discharges into the ocean: a dam for water supply and a shallow lake. We analyzed the spatial distribution of the phytoplankton community, the physicochemical parameters, and the metal concentrations in the particulate fraction. According to the trophic indices and the phytoplankton abundance, composition and diversity, the water quality showed significant deterioration in the lower basin after the Sauce Grande lake. The conductivity, turbidity and most metal concentrations increased towards the downstream area, even exceeding recommended levels for some metals. This study generates a database for the water quality of the Sauce Grande River Basin and its contribution to the sea. It shows an example of how the water quality varies along a basin that crosses different topographic environments and land covers.