Keywords: water pollution, industrial effluents, dissolved oxygen, water quality indices, WQI, Brazil
Water quality of a stream receiving industrial effluents, located in the Brazilian Northeast
Industries, as a source of pollution, have a considerable impact on water resources due to the diversity in the composition of their effluents. The Mussure Stream was chosen for this study because it flows across the industrial district of Joao Pessoa, in Northeast Brazil, and is the main receiver of liquid effluents, which are disposed into the stream almost exclusively without adequate treatment. The objectives of this study are to use the water quality index WQIB to give an overview of the impact of the industrial effluents on the quality of the water of the Mussure Stream, as well as the comparison of the content of dissolved oxygen found in the water with the minimum values required by the effective legislation. The results indicated that the water of the Mussure Stream presented levels of dissolved oxygen that were below that which could be considered satisfactory and the water was classified according to the WQIB, during the two years of the study, between 35 and 49, for all collecting stations, indicating low water quality and a potential risk for the population.