Evaluation of water quality parameters for monitoring natural, urban, and agricultural areas in the Brazilian Cerrado

Daphne Heloisa De Freitas Muniz,Aline Silva Moraes,Jorge Enoch Furquim Werneck Lima,Eduardo Cyrino Oliveira-Filho,Carlos José Domingos Da Cruz,Ingrid De Souza Freire

doi:10.1590/s2179-975x2012005000009

Daphne Heloisa De Freitas Muniz, Aline Silva Moraes + Show 4 more

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https://doi.org/10.1590/s2179-975x2012005000009

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Abstract

INTRODUCTION: Brazil's Federal District (FD) has seen steep population growth in recent years, and this has increased demand for high-quality water. AIM: The present work aims to evaluate the quality of surface water from two water bodies in the FD at six sampling points, three of which are in the Sobradinho River (the receiving body of a sewage treatment plant effluent) and three in the Jardim River (located in an agricultural region). METHODS: Analyses were carried out every thirty days, for twelve months, covering rainy and dry seasons. Parameters were analyzed such as temperature, pH, dissolved oxygen (DO), conductivity, turbidity, total hardness, main ions, total and fecal coliforms (E. coli) in water. Ecotoxicological evaluation was also performed, using the micro-crustacean Ceriodaphnia dubia. RESULTS: Data of physical and chemical determinations showed DO, conductivity, Cl-, NO3-, SO4(2-) and Na+ to be important in indicating contamination by urban effluents. On the subject of biological parameters - E. coli and ecotoxicological evaluation - the former was seen to be more effective in the urban area. However, in the countryside, the assay with C. dubia proved to be the most sensitive, although less than ideal, because the organism is very sensitive to low water hardness. CONCLUSIONS: The fecal coliform indicator (E. coli) was the most effective one for comparing water quality in the two basins, mainly for the urbanized one, while ecotoxicity assays with C. dubia were harmed by the natural chemical composition of the water.

Highlights

Brazil’s Federal District (FD) has seen steep population growth in recent years, and this has increased demand for high-quality water
The Sobradinho River, an important tributary of the São Bartolomeu River, is part of the fundamental drainage network for the FD and, it does not supply the local population with drinking water, it dilutes domestic effluents and follows its course to contribute to the flow of large rivers
Data from this work show that the ecosystem of the Sobradinho River basin is considerably disturbed, and that the increase in urban occupation is responsible for the intensification of environmental degradation processes in this basin

Summary

Introduction

Brazil’s Federal District (FD) has seen steep population growth in recent years, and this has increased demand for high-quality water. Methods: Analyses were carried out every thirty days, for twelve months, covering rainy and dry seasons Parameters were analyzed such as temperature, pH, dissolved oxygen (DO), conductivity, turbidity, total hardness, main ions, total and fecal coliforms (E. coli) in water. Conclusions: The fecal coliform indicator (E. coli) was the most effective one for comparing water quality in the two basins, mainly for the urbanized one, while ecotoxicity assays with C. dubia were harmed by the natural chemical composition of the water. Water ecosystems have undergone profound changes in recent years, mainly due to human activities, at a range of levels. The main sanitary sources of contamination in the District’s water bodies come from domestic effluents, sewage treatment plants, garbage dumps and cemeteries; the main farming sources stem from the frequent use and handling of pesticides, fertilizers and manure; services are involved, such as gasoline stations, bus depots, and industries, albeit few in number (Barros, 2005)

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