Proposta metodológica para avaliação de condições de balneabilidade em águas doces no Brasil

Abstract

The water use for leisure activities has always been present in human culture, especially in countries with a favorable climate and a wealth of water resources, where there are appropriate conditions for recreational activities practice that involving primary contact with water of rivers, waterfalls, dams and ponds. However, this use demands specific requirements of water quality, once the primary contact requires a more restrictive assessment of water quality, due to the risks posed towards to human health by direct and prolonged exposure to pathogenic organisms and toxic substances. In Brazil there is a lack of proper monitoring ofbathing waters conditions and, in addition, the currently used methodology shows some limitations, as the use of some microbiological indicators that do not set standards for otherfactors and/or elements which may interfere with the use of recreational waters for the purpose of primary contact. In this context, this study's general objective is the development of a methodology to assess water quality for bathing in freshwater, in order to improve the current methodology, establishing new variables for the analysis of bathing water conditions by the use of Delphi methodology; composing an integrated index of water quality for bathing to cover the main elements raised; proposing a protocol for the integrated assessment of bathing places, taking into consideration sanitary, aesthetic and safety aspects. According to the results obtained with experts from universities, environmental agencies and sanitation companies, the methodology to assess the conditions of bathing in fresh water must include new parameters, mainly the assessment of water contamination by cyanobacteria and visual or aesthetic variables. A water quality index was proposed, based on the minimum operator method, including the variables Escherichia coli, cyanobacteria density, turbidity and pH,that, according the final index results, classifies the water quality in Excellent, Very Good, Suitable, Unsuitable and Very poor. Therefore, this study is intended to contribute to the management process of recreational water use, aiming the improvement of the evaluation andpropagation of bathing freshwaters conditions to ensure better health conditions to frequent users.