Human influences on water quality of São Miguel river watershed, upper São Francisco karst, Minas Gerais

Abstract

The water quality is one of the elements that can potentially
indicate human activities in watersheds. This study was based in water analysis conducted at São Miguel river basin, located in
karstic terrain in Upper São Francisco basin. Monthly, during a
year, samples were collected at 5 gauge stations in São Miguel
river to monitoring 13 water quality variables. Those, which had
demonstrated human influences, were studied spatially and
temporally. Sewage discharge from urban area, although its
relatively small size, was the main factor of water pollution in the river, being responsible for microbiological contamination,
resulting in waterborne disease cases - schistosomosis was
reported at the middle sector of the river. The effects of rural
activities in water quality decay were evidenced at rainy season
due soil erosion at, both in the up and low river course. The
variables analyzed did not indicate clearly effects of limestone
mining in the water quality, nonetheless it represents the major
economic activity at the region.