Avaliação da qualidade da água do trecho do Rio Piancó na bacia hidrográfica Piancó-Piranhas Açu

Abstract

Paraíba has about 90% of its territory in the semi-arid region of Northeast and it is in this context that the Piancó Piranhas-Açu River Basin is inserted. Piancó River basin, the aim of this work, has a storage capacity of 1,846,126,108 m3, where the largest water reserve is located, formed by two interconnected reservoirs: the Coremas - Mãe D'Água System, with a storage capacity of 1.358 billion m3 of water. The maintenance of the water quality of this river is of utmost importance since the stretch of Piancó River is responsible for urban and rural supply, and guarantees the hydric sustainability of the agricultural and agro-industrial activities of this region. In this context, this work is inserted: to evaluate the stretch of Piancó River, which is perennialized by the Coremas - Mãe d'água Reservoir, and establish physical-chemical and biological parameters and evaluate the water quality of Piancó River. The collections were performed at 2 fixed stations PC01 and PC02 in the period from 2011 to 2020. To analyze the natural characteristics, identify possible sources of pollution parameters such as Temperature, pH, Color, Turbidity, TDS, DO, BOD and thermotolerant coliforms that represent the physical, chemical and biological aspects of the water were analyzed. For Coremas-Mãe D'ÁGUA Dam, besides these parameters, Water Quality Index was also determined. The results were evaluated according to the respective limits for class 2 water bodies defined by CONAMA Resolution No. 357/2005. It was found that most of the parameters are in accordance with CONAMA Resolution 357/2005. However, the values found for Electrical Conductivity, Total Dissolved Solids, Dissolved Oxygen and Thermotolerant Coliforms are indicative of pollutant load released into the watercourse. The water quality index of Mãe d'água - Coremas reservoirs was classified as good, excellent and acceptable. Thus, it is concluded that these dams do not influence negatively the water quality of Piancó River. Thus, the quality of the water along the Piancó river basin is entirely linked to urban growth and the lack of basic sanitation in its surroundings.