Análise comparativa de legislações relativas à qualidade da água para consumo humano na América do Sul

Abstract

This work aimed at evaluating and comparatively discussing the legislation regarding drinking water quality, control and surveillance in South American countries, analyzing its coverage and updating.In most countries, requirements on quality control are limited to sampling and checking the drinking water standards. Regulation on water quality surveillance is rare. In fact, apart from Brazil and Colombia, few countries approach control and surveillance activities on a broad, balanced and integrated basis. Another aspect to be observed is the rather undefinedinstitutional role of water quality surveillance, since only in Brazil and Colombia such activities are clearly and entirely in charge of health authorities. Regarding microbiological standards, in spite of the growing recognition of the limitations of coliforms organisms in fulfilling the role of a water quality index, few countries use complementary indicators such as filtered effluents turbidity and the control of the disinfection process.With respect to physical and chemical standards, most of the legislations follow the WHO contemporary recommendations, but paying central attention to aesthetic parameters and inorganic substances. When it comes to organic substances, agricultural pesticides and disinfectant byproducts, significant differences in the number of regulated parameters are registered; furthermore, some legislations simply do not mention some of these parameters. Using the Fuzzy-C means clustering method, the legislations resembled each other, according to the evaluated parameters. The clearest results (grouping similar standards) were obtained for orga nic substances, agricultural pesticides and disinfectant byproducts, exactly because of the larger differences amongst them.Considerable differences were found among the South American legislations, with regards to updating, coverage and drinking water quality assessment criteria. The sort of information provided by this study suggests that there is room for a closer interaction between South American countries in order to try and build up more consensual and harmonized approaches.