Anthropic activities performed in a river basin, especially those that promote changes in the soil surface, have great effect on the quality of the waters in the basin. Thus, the objective of this study was to evaluate water quality by applying the Water Quality Index (WQI) in springs and watercourses located in an area with different land use and occupation characteristics, as well as to compare the analyzed variables with the standards established for class 2 of the National Environmental Council (CONAMA, for its acronym in Portuguese) Resolution No. 357/2005. Seven sampling points located in the rural area of the municipality of Jacutinga, Minas Gerais State (MG), were monitored. The water samples were collected from October 2018 to July 2019. Comparison with the resolution showed that the quality condition was lower than the standard established for class 2 in most campaigns conducted. Regarding the mean WQI, the water quality at points S1, WC1, WC2, and WC3 was classified as "average," while the water quality at points S2, S3, and S4 was classified as "good." There was seasonal variation in the WQI only at point WC1. Overall, thermotolerant coliforms (TC), nitrate, and phosphorus are the main factors deteriorating water quality, and it may be directly related to the agricultural activities practiced in the monitored areas.
Keywords: Brazilian normative standards; Seasonal variation; Thermotolerant coliforms; Water quality index; Water resources.
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