Efeito do uso do solo na qualidade de águas superficiais em áreas de influência urbana na cidade de Boa Vista – RR

Abstract

The areas of water bodies are of great environmental and urban importance, as, in addition to being responsible for important environmental interactions, their multiple functions started to contribute to the structuring of cities and, consequently, to integrate the urban landscape. Thus, this research aimed to analyze the effects of land use on the water quality of the Grande and Auai Grande streams, located in an area of urban influence in the city of Boa Vista - RR. For the development of this research, the qualitative-quantitative methods and exploratory approach were used. In the preparation of land use and occupation maps, LandSat 8 satellite images were used, using Corel Draw Graphics 2020 and Quantum GIS 3.18 software for processing. Obeying the recommendations of NBR No. 9898 of June 1987, covering the dry and rainy periods, the collections were carried out in June and September 2019 and in April and October 2020, in each of the three sampling points defined along the two streams. According to the methodologies described by the American Public Health Association (APHA), the parameters temperature, pH, electrical conductivity, turbidity, total solids, dissolved oxygen, biochemical oxygen demand, total coliforms and Escherichia coli were analyzed in the Effluent Laboratory of the Roraima Water and Sewage Company (CAER) and the results were compared to CONAMA Resolutions nº 357/2005 and nº 274/2000. The statistics of the results were submitted to analysis of variance (ANOVA) and Tukey's test at 5% probability. The results showed that the micro basin areas of the Grande and Auai Grande streams have different use and occupation. While the first is marked by an intense human presence, especially the installation of the municipality's stabilization pond on its banks, the second, with less urban characteristics, has the sanitary landfill as its main class of use and occupation. Thus, the variance tests showed for all parameters, except for total solids, OD and BOD, the condition of occurrence of significant variability between the results of the rainy and dry seasons of the two streams. Another relevant aspect concerns the collection points located near the landfill and the stabilization pond, which, almost unanimously, showed higher contamination levels in all samples during the dry and rainy season than the upstream and downstream points. downstream to them, thus indicating the constant supply of polluting load in these specific regions, that is, both the landfill and the stabilization pond can be considered diffuse sources of contamination of the waters of the streams. That said, in general, through the results of the analyses, it was possible to conclude that the waters of both streams are considered unsuitable for use, according to the standards established by CONAMA Resolutions nº 357/2005 and nº 274/2000.