A influência do uso e ocupação do solo para qualidade de água da bacia do Mucugê, município de Porto Seguro - Bahia

Abstract

Water resources are part of only 0.01% of the water of the entire planet and are of paramount importance for human development, supply, recreational use, serve as habitat for various aquatic organisms and thirst for various land animals. However, due to population growth, the use and occupation of the land has affected the quality and quantity of these resources that are of paramount importance for life. This study was divided into two chapters: the first was an analysis of the modifications of the types of land use and occupation in the Mucugê basin, present in the district of Arraial D'Ajuda, municipality of Porto Seguro - Bahia in the last 36 years (1985-2021). With the use of Qgis Software (version 3.22.7) and data generated by the Mapbiomas Project it was possible to identify categories of Forest Formation, other non-forest formations, flooded field and swampy area, Mosaic of uses, pasture, beach, urban area and non-vegetated areas. Between the years 1985 to 2021, the territorial area of the basin lost 46% of forest formation and in return the urban area grew by about 91.02%, occupying itself in all other classified areas. In the second chapter, a diagnostic study is being carried out on the water quality. With in situ and laboratory analyzes to determine pH, BOD, dissolved oxygen (DO), total phosphorus, dissolved phosphorus, temperature, chlorophyll-a, turbidity and metals (Cr, Cd, Pb, Al, and Cu) in water it was possible to identify values outside the limits legislated by CONAMA 357/05, for BOD (1.82-20.71 UNT), Total Phosphorus (0.080-7.0 mg/L) and DO (0.56-5.22 mg/L). Some metals were also identified above the legislated limits with ranges of 0.009-0.150 mg.L⁻¹ for Cu, 0.013-0.591 mg.L⁻¹ for Al, 0.005-0.6 mg.L⁻¹ for Cd and 0.002- 0.60.mg.L⁻¹ for Pb.Caffeine was quantified in 4 of the five sampling points. With the assessments of the Pollution Load (PLI), Integrated Threshold Pollution (IPIth) and Potential Ecological Risk (PERI) indices, it was possible to reveal high levels of pollution by potentially toxic metals at the sampling points, indicating an ecological risk for the basin's ecosystem. With the data obtained, it was possible to identify the contribution of land use and occupation to pollution in the Mucugê basin.