Monitoramento ambiental da bacia hidrográfica do rio Guandu

Abstract

The sustainable management of water resources has become a pressing challenge in contemporary times and on a global scale, demanding an integrated and multidisciplinary approach to understand and address the complex interactions affecting water quality. Within this context, the research begins with a literature review of relevant topics to the subject, in which a theoretical framework was developed based on the presented issues. With the assistance of the ArcGIS program and bibliographic references, the characteristics of the Guandu River watershed were surveyed to select sampling points. Monthly field collections were conducted between January and July 2023 at five distinct points, three along the Guandu River, one along the Poços River, and the last one along the Queimados River, for laboratory assays including ecotoxicity tests, physicochemical analyses for the elaboration of IQA-NSF and IQA-CETESB, and detection of pesticides. The results revealed significant variations in levels of total coliforms, BOD, phosphate, and nitrate, highlighting potential sources of contamination impacting the health of aquatic ecosystems. The sampling points, especially point 4 (Poços River) and point 5 (Queimados River), exhibited alarming results across all analyzed parameters, indicating the influence of human activities such as discharge of untreated sewage and industrial activities. These findings are inconsistent with the standards set by CONAMA Resolution 357/2005, underscoring the need for urgent corrective measures to mitigate the already-present negative impacts on water quality. Additionally, the Water Quality Index results revealed predominance of poor and fair classifications, demonstrating the overall degradation of the entire Guandu River watershed. Ecotoxicity analyses using the test organisms Raphdocelis subcapitata and Vibrio fischeri showed a high mortality rate among organisms, indicating an adverse aquatic environment, possibly exacerbated by the detection of the pesticide Diuron in water. Finally, based on the presented data, discussions were raised regarding the achievement of Sustainable Development Goals outlined in the 2030 agenda, the assessment of impacted ecosystem services, and the proposal of environmental recovery and mitigation methods aimed at improving the quality and restoring the original characteristics of the studied water bodies.