Estudo do índice de qualidade das águas nas sub-bacias do médio e baixo Jaguaribe

Abstract

The increasing demand for potable water makes the question of the quality of this resource important in order to guarantee the minimum conditions for its ingestion and use for hygienic purposes. The water quality indexes are used to quantify this aspect. One of these indices is the Water Quality Index (WQI), developed by the National Sanitation Foundation (NSF), which calculates the quality based on nine parameters: dissolved oxygen, biochemical oxygen demand, pH, thermotolerant coliforms, nitrate, total phosphate, temperature, turbidity, and total solids. This work aimed to analyze the water quality of the sub-basins of the Middle and Low Jaguaribe, Ceará, through the IQA. The sub-basin monitoring data were applied in equations to determine the score of each parameter required in the calculation of the IQA. The IQA values of the Lower Jaguaribe sub-basin varied between 52 and 88, while the Jaguaribe Medium sub-basin had IQA values between 58 and 82. When compared, the Jaguaribe Medium sub-basin presented better quality results water, with lower quality variation among the samples collected. However, both presented an average in the classification range of good quality, that is, water is appropriate for public supply, provided that they undergo appropriate treatment.