Water quality assessment in watersheds with different anthropogenic impacts

The unbalanced use of soil without a proper conservationist treatment as well as the improper anthropogenic actions may cause alterations in the local water quality and can induce the pollution of water resources. This study aimed to evaluate the water quality in watersheds with distinct use and occupation of the soil of the Vacacaí-Mirim River in the municipality of Santa Maria, Rio Grande do Sul, Brazil. Water quality parameters were statistically analyzed in periods of dry weather and assessed using the Pearson correlation coefficient. Alto da Colina watershed, with the smallest area (2 km²), presented the highest percentage of urbanization and the largest population; however, it showed the worst results regarding environmental degradation when compared to the other watersheds studied. This result is due to the influence of the domestic effluent as a potential source of contamination of the water system and due to the high contribution of organic matter, pathogenic agents, and nutrients. The different uses of soil have caused alterations in the relations between the water quality parameters analyzed. In watersheds where agricultural areas are predominant, the influence of turbidity and suspended solids was significant due to the occurrence of erosive processes.

water quality; land use; anthropogenic activity; environmental degradation