Research article


Jesús Rascón, Nilton Luis Murga Valderrama, Damaris Leiva-Tafur, Pablo-Alfredo Rituay Trujillo, Manuel Oliva-Cruz, Jonathan-Alberto Campos Trigoso, Rainer M. López Lapa, Jorge L. Maicelo

Online First: November 11, 2022

The Olía and Ventilla river basins are two adjacent watersheds located in the montane forest region of northeastern Peru. The main economic activity along both watersheds is extensive free-grazing cattle ranching, where cattle have unrestricted access to water sources. The surrounding populations use these waters for human and animal consumption. The study's main objective was to determine the spatiotemporal variability of microbiological quality. Microbiological parameters were determined in both basins, in the wet and dry seasons, comparing the values obtained with the national standards for water quality according to the type of use. Two points were established per basin, one in the upper and the other in the lower. Microbiological parameters of total coliforms (TC), fecal or thermotolerant coliforms (TC), and Escherichia coli (EC) were determined using the Most Probable Number technique. The results reveal that in the Olia river basin, in the wet season, a mean of 1395.35, 1353.63, and 475.56 MPN/100 ml was obtained for TC, CF, and EC, respectively, and a mean of 1367.64, 1056.44 and 961.86 MPN/100 ml for TC, CF, and EC, in the dry season. While in the Ventilla river basin in the wet season, a mean of 1282.14, 1290.23, and 992.55 MPN/100 ml was obtained for CT, CF, and EC, respectively, and a mean of 1616.43, 1612.95, and 1345.31 MPN/100 ml for CT, CF, and EC, in the dry season. Both watersheds showed spatial but not temporal variation for microbiological quality. Comparison with national standards showed that the lower part of both basins exceeded the limits for water for animal consumption. At the same time, water for human consumption with disinfection exceeds the limits in both basins for all points. All these results were statistically significant (p-0.05). Therefore, the Olia and Ventilla river basins present low microbiological quality, marked by spatial variability. This generates that using water for humans and animals increases the incidence of gastrointestinal diseases.


Water, coliforms, fecal contamination, livestock, Andes.