Abstract

SOTOMAYOR, F et al. Determination of the microbiological quality of the water of artesian wells in the districts of Central and Cordillera departments and the capital. Mem. Inst. Investig. Cienc. Salud [online]. 2013, vol.11, n.1, pp.5-14. ISSN 1812-9528.

Among the major sources that supply drinkable water are the aquifers which are geological formations that store water and act as a deposit and reserve, being in the entire terrestrial surface. Their exploitation is performed by artesian wells and the increasing demand for drinkable water in densely populated areas has forced the installation of these wells. The aim of this study was to determine the degree of contamination expressed by the concentration of fecal, total coliforms and aerobic mesophilic bacteria in samples of water from artesian wells from the Central and Cordillera departments and the capital city, within the limits of the Patiño aquifer outcrop. We evaluated 57 water samples from artesian wells of 20 to 130 m depth, treated and untreated, that were sent to INTN by owners of artesian wells and water sellers in 2008. We used the multiple tube technique for the determination of total and fecal coliforms and the most probable number for aerobic mesophiles. Of the samples, 58% (33/57) were classified as contaminated. In treated water, 12.5, 40.0 and 31.2% of fecal coliforms, aerobic mesophiles and total coliforms respectively had values outside the permitted limits.In untreated water,19.5,61.5 and 48.8 % of fecal coliforms, aerobic mesophiles and total coliforms respectively had values outside the permitted limits by the provisions of the Paraguayan Standard 24 001 80 (5th edition). It is important to detect microbiological contamination in groundwater, as they are sources of drinkable water.

Keywords : aquifer; artesian well; microbiological quality.

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