Estudos ambientais em bacias hidrográficas: a utilização do modelo força motriz, pressão, estado, impacto e resposta

Abstract

The economic activities developed in the area of the hydrographic basins, have a high degrading potential for the water resources. In this sense, integrated environmental studies are important tools that help in the process of managing these resources. The DPSIR model (driving force, pressures, state, impacts, and responses) is an example of an integrated environmental approach that allows monitoring of society-environment relations and is considered an internationally accepted conceptual standard. The present research aims to apply the DPSIR model to identify, characterize and analyze the cause and effect relationships of socioeconomic activities in the basin of influence of the Castanhão reservoir. The study area has approximately 6,080-km² covering a total of nine municipalities. Among the natural driving forces affecting the basin are the atmospheric entrances and the physical and chemical denudation of the soils. Among the anthropic ones, there are the diffuse sources of contamination and environmental change, related to agriculture and urbanization. It should be emphasized that the category "driving force" is based on the contribution of nitrogen and phosphorus elements to the studied river basin. The pressures were identified and the impacts quantified, using as subsidy the calculation of the N and P load estimates for the identified driving forces. Through the activities that presented risk to the basin due to its pollutant loads, the category "answers" was presented. It was concluded that urbanization, with its effluents, agriculture and livestock, agriculture with fertilizers, pesticides and animal waste, presents potential sources of contaminants due to the contribution of nutrients, which can result in an environmental imbalance and increase human exposure to contaminants. The DPSIR model provided an integrated analysis of the environmental problems generated by economic activities and was able to provide subsidies to the planning and environmental management of a river basin through mitigation actions that can be fostered by public administrations, civil society and economic sectors.