Suchergebnisse

Water quality issues are a growing concern due to the the recent intensification of urbanization and industrialization. This paper evaluates and compares the surface water quality of the ten sub-basins of the Pará River, located in the São Francisco River Basin, Minas Gerais, and evaluates the impact of seasonality and the compliance with the current limits of state legislation. The surface water quality monitoring database of the Institute of Water Management of Minas Gerais (Igam) was used, and 18 parameters were analyzed from a historical series from 2008 to 2016, totaling 16,651 observations. First, the descriptive statistics of the parameters were calculated, considering each sub-basin separately. Then, for the temporal and spatial analysis, the Kruskal-Wallis nonparametric statistical tests were applied, followed by the multiple comparison test, with an alpha level of 5%, due to the asymmetric behavior of the data. Thus, it was possible to compare water quality of the sub-basins in rainy and dry seasons and to identify which parameters were responsible for the greater degradation. In the compliance analysis to the current limits of state legislation, it was identified that all of the sub-basins were out of the specified range for at least one of the evaluated parameters. Finally, the seasonality analysis exposed significant differences in the parameters of dissolved oxygen, turbidity, total suspended solids, total solids and water temperature, where it was shown that there was a worsening of water quality in the rainy season for most sub-basins. ; Water quality issues are a growing concern due to the the recent intensification of urbanization and industrialization. This paper evaluates and compares the surface water quality of the ten sub-basins of the Pará River, located in the São Francisco River Basin, Minas Gerais, and evaluates the impact of seasonality and the compliance with the current limits of state legislation. The surface water quality monitoring database of the Institute of Water Management of Minas Gerais (Igam) was used, and 18 parameters were analyzed from a historical series from 2008 to 2016, totaling 16,651 observations. First, the descriptive statistics of the parameters were calculated, considering each sub-basin separately. Then, for the temporal and spatial analysis, the Kruskal-Wallis nonparametric statistical tests were applied, followed by the multiple comparison test, with an alpha level of 5%, due to the asymmetric behavior of the data. Thus, it was possible to compare water quality of the sub-basins in rainy and dry seasons and to identify which parameters were responsible for the greater degradation. In the compliance analysis to the current limits of state legislation, it was identified that all of the sub-basins were out of the specified range for at least one of the evaluated parameters. Finally, the seasonality analysis exposed significant differences in the parameters of dissolved oxygen, turbidity, total suspended solids, total solids and water temperature, where it was shown that there was a worsening of water quality in the rainy season for most sub-basins. ; As questões de qualidade da água são uma crescente preocupação com a recente intensificação da urbanização e industrialização de grande parte das bacias hidrográficas. Este trabalho propõe avaliar e comparar a qualidade das águas superficiais das dez sub-bacias do rio Pará, localizadas na Bacia do rio São Francisco, Minas Gerais, além de verificar o impacto da sazonalidade e o atendimento aos limites da legislação estadual vigente. Foi utilizado o banco de dados de monitoramento da qualidade das águas superficiais do Instituto Mineiro de Gestão das Águas (Igam), sendo analisados 18 parâmetros oriundos de uma série histórica de 2008 a 2016, em um total de 16.651 observações. Primeiramente, foi calculada a estatística descritiva dos parâmetros, considerando cada sub-bacia separadamente. Em seguida, para a análise espacial e temporal, foram aplicados os testes estatísticos não paramétricos de Kruskal-Wallis, seguido pelo teste de comparações múltiplas, ao nível de significância de 5%, face ao comportamento assimétrico dos dados. Assim, foi possível comparar a qualidade da água das sub-bacias nos períodos chuvoso e seco e identificar quais parâmetros foram responsáveis pela maior degradação. Na análise do atendimento à legislação e ao enquadramento, identificou-se que todas as sub-bacias se mostraram fora do enquadramento para, pelo menos, um dos parâmetros avaliados. Por fim, a análise da sazonalidade apontou diferenças significativas nos parâmetros OD, turbidez, sólidos em suspensão totais, sólidos totais e temperatura da água onde foi demonstrado que houve uma piora da qualidade da água no período chuvoso para a maioria das sub-bacias.