Análise de risco ecológico da cabeceira de um ribeirão urbano

Abstract

The interactions between organisms and the abiotic components of aquatic ecosystems are dynamic and complex, tending to a natural balance over time. When part of this equilibrium is disturbed, a strong chain reaction occurs, unpredictable consequences for the ecosystem structure can occur. In order to carry a systemic analyzes of these consequences, considering the fundamental need for the management of hydrological resources, the protocol of Ecological Risk Analysis (ERA) was applied to an urban stream potentially contaminated. This tool has been used in the academic and professional environments. Using triad methodology, seeking to reduce the subjectivity of the analyzes and primary and secondary data bases (limnological data, land use, cadmium concentration, biomarkers, richness and abundance of aquatic organisms), the risk analysis calculated the integrated risk based on the estimation of the chemical, toxicological and ecological risk of three sampling stations. The risks identified for the Cambé stream stations were high in the first two and low in the third one. The chemical risk was only high in the second station of the Cambé stream, the toxicological risk was very low in all stations and the ecological risk was high in all station mainly because of the difference between the ichthyofauna’s composition in the Cambé stream and in the reference creek of this study. Based on the results of each line of evidence and in previous researches, the continuity of the study with analyzes of more parameters was suggested. Finally, it was recommended as risk management measures a revegetation program for the ciliary forest and a monitoring of the headwaters of the Cambé stream.