Evaluation of groundwater quality: Vilhena case study - RO

The groundwater of the Parecis Aquifer (PA) represents the only source of public drinking water supply in the VilhenaCity, RO. In this way, an evaluation of water quality determined by physical, chemical and microbiological analyzes can provide data to understand the consumed water conditions. In the present study, two groundwater collections were performed in 12 wells distributed around the city: the first one in the dry season, in August 2013; and the second one in rainy season, in December of 2013. The parameters analyzed were the ionic constituents (F-, Cl-, NO2-,Br-,NO3-,PO4-3,SO4-2,Na+,NH4+, K+,Ca2+ eMg2+) that were quantified by ion chromatography, while for microbiological analysis, the method utilized was the chromogenic media used in membranes filtration. The parameters pH and turbidity were measured using a portable pH meter, and a portable turbidimeter. The results showed values below the limits established by CONAMA Resolution396/2008 and the MS Directive 2914/2011for turbidity and all of ionic constituents, except for nitrate (6 wells)and ammonium (1 well), as well as presence of acid pH. The rainy season presented more contamination by Escherichia coli and total coliforms than the dry period, and it can be associated with bad conditions of wells, besides it is an unconfined aquifer, it has been facilitating the flow of possible contaminants. The results shown the importance of a constant monitoring in the water quality in communities that have been using alternative sources, avoiding problems related to human health.