Impacto sócioambiental do lançamento de percolado e esgoto nos recursos hídricos: o caso da Lagoa do Borzeguim, Itapipoca–CE

Abstract

The municipality of Itapipoca is located in the northern region of the state of Ceara, some 133 km from the capital, Fortaleza. Its population is estimated at 114 000 inhabitants and the city faces an environmental problem common to other cities in Ceará: the disposal of solid waste in landfills. The landfill site at Itapipoca was installed in 2002 in an area of great socio-environmental vulnerability, near a large pond and a community that uses it for economic activities and direct consumption. The community of Borzeguim - the eponymous name of the pond - has about 50 families that since 2002 protest against the placement of the landfill. Nevertheless, in 2004, was installed a sewage treatment plant, with effluent being released in the same water system impacted by landfill. The inexistence of such a study of the region that would let us know the real impact of such practices, motivated the conception of the present work. Thus, our goal is to analyze the social and environmental impacts arising from inadequate disposal of solid and liquid waste in the water resources of the community above. The specific objectives are to assess the social impact of inadequate disposal of solid waste on the population that resides in the vicinity of the landfill and to evaluate the water quality of the water system under study, identifying the parameters that exceed the limits established by CONAMA 357/2005, and simulate the behavior of self-purification of the stretch under study considering the measure of dissolved oxygen. In order to do so, we conducted semi-structured interviews with a sample of the community, including human scavengers found in the landfill, with a view at addressing the social diagnosis of the area. In order to diagnose physical and environmental quality of surface water, four campaigns were conducted, analyzing the following parameters: DO, BOD, pH, fecal coliform, E. Coli, salinity and Secchi transparency. We simulated the behavior of self-purification of the water system under study using the modeling of water quality proposed by Streeter & Phelps and the load of BOD. With that, we reached the following conclusions: 1) the landfill and STS cause problems to the community of Borzeguim, emmiting stink, provoking their rejection (by the members of other communities) and causing real estate depreciation, as well as disturbing the relationship between community and pond. 2) the landfill causes strong depletion of DO in the creek while the STS retards the reaeration system, 3) the pond is eutrophic, has excessive presence of microalgae on the surface, high rate of primary productivity and diminute photic zone. 4) the pollution load coming from the city is an important factor in the degradation of the pond. These conclusions evidentiate the indispensability of further interdisciplinary studies on the issue of solid waste disposal on the Borzeguim area to serve as a subsidy to plans for restoration of similar degraded areas and as a subsidy to plans for their subsequent sustainable management and, more immediately, as a technical foundation of any proposals for the adoption of those plans.