Water quality indicators in river basins – A Portuguese case study (Northern Portugal)

Abstract

The objective of this work is the identification of the main contamination sources in the Vizela river watershed and the potential effects on water qual-ity. The physico-chemical parameters temperature, pH, Total Dissolved Sol-ids (TDS), electrical conductivity (EC), redox potential (Eh), and chloride, fluoride, bromide, nitrite, nitrate, sulfate and phosphate water contents were analyzed. The microbiological parameters Escherichia coli and intestinal en-terococci were monitored over the time. The obtained results indicate that the water located downstream Vizela river is the most contaminated, alt-hough there has been an improvement in water quality over the time. The microbiological contents are higher than parametric Portuguese values de-fined for human consumption, and often also the parametric values defined for recreation water activities. As a preventive and monitoring measure, it is recommended to monitor the various physico-chemical and microbiological parameters in water points, with a spatial and temporal regular and constant monitoring.