Avaliação de impacto ambiental e da qualidade da água na zona urbana de Crateús-CE

Abstract

The Poti river is inserted in the west zone of Crateús city, state of Ceará, being classified as freshwater class 02 by CONAMA (Environmental National Council) resolution 357/2005. In this sense, the aim was to analyze the geoenvironmental characteristics of the area, and the land use and cover, identifying environmental and socioeconomic impacts, with focus in Poti river water quality and groundwater in the urban zone of Crateús – CE. Methodology consisted of sampling groundwater and Poti river water during the drought and rainy period of 2011 to 2012 for physicochemical and biological analyses. Results of Poti river water analyses were used for calculating Water Quality Index (WQI) and Trophic State Index (TSI). The matrix elaborated for environmental and socioeconomic impacts identified the main positive and negative impacts. Groundwater results showed only one well of good quality, while water from other wells was brackish, but they can be used as alternative water sources in years of prolonged drought. WQI Poti river was classified as good, but at some points showed regular quality. Shortage of water along the river made the water remained stagnant, presenting brackish water at some points. TSI showed a hipereutrophic state for the river, with massive presence of macrophytes at some points and also cyanobacteria, which might produce toxins harmful to human health. Environmental impact matrix presented planning and management failure. Among negative environmental impacts, it stood out animal presence on river banks, while as positive impact, selective garbage collection appeared as mitigating measure. Therefore, water resource management should consider local peculiarities, giving priority to majors for sustainable development, such as sanitary sewage system expansion, which is fundamental for public health and city urbanization, searching better quality of life for local population.