Avaliação físico-química, microbiológica e quantificação de metais em águas superficiais no ribeirão Taquaruçu grande, Palmas-TO

Abstract

The Taquaruçu Grande stream, by its geographical position, forms the most important subbasin of Palmas-TO. The impacts of disorderly urban growth and rural activities have been destroying riparian forests, altering water quality, reducing flow and causing the total extinction of some water courses in the region. Considering these factors, 5 collection points were defined along the Taquaruçu Grande stream, in order to evaluate the water quality of this water body through physical-chemical and microbiological parameters, in addition to analyzing the concentrations of metals present in it. The legislation adopted to compare the results was CONAMA 357/05, which provides for the classification of bodies of water and guidelines for their classification, as well as establishing the conditions and standards for effluent discharge. After collecting the samples, the analysis of the results was performed, point P1 did not present any value in disagreement with the applicable legislation. Point P2 also did not exceed the limits established by CONAMA 357/05, however there was a certain increase in the parameters of metals. Point P3 exceeded the maximum limit for the parameters of True Color and E. coli Among the evaluated points, point P4 was the one that presented the most parameters in disagreement with the legislation, pH, BOD, Ammonia and Chlorophyll-a, in addition to high values of Total Suspended Solids, a parameter not limited by CONAMA 357/05. Point P5 exceeded the maximum limits of the legislation only for Chlorophyll-a. The results allowed us to conclude that factors such as soil vulnerability in the rainy season, sedimentary structure of the basin susceptible to erosion, phosphate richness in the Taquaruçu Grande stream and the release of inadequate effluent by the ETE Aureny may be the main causes of the poor quality of water, especially in the last three points of the stream.