The contributions of nutrients and xenobiotics by anthropogenic activities developed in riverside deteriorate water quality. In this context, the impact of different agroindustry effluents on the water quality of Salado River in Buenos Aires Province (Argentina) was analyzed applying water quality indexes (WQI). Water quality index is an efficient a simple monitoring tool to instrument corrective and remediation policies. Winter and summer samplings were performed. A minimal water quality index (WQImin) was calculated using only two parameters which can be easy determined in situ. The use of WQImin may be a useful methodology for river management. Meat industry appears as the most pollutant source. Since it is considered as point pollution source, effluents should be treated previous to its disposal with the available technologies.