Microbiological quality of drinking water in three rural communities of the Calvas County (Loja)

Abstract

In Ecuador, rural areas face difficulties in accessing safe drinking water due to the contamination of water sources by biological waste or agricultural runoff, which turns water into a vehicle for potentially pathogenic microorganisms. Therefore, a microbiological assessment was carried out in three communities of the Calvas County, analyzing total coliforms, protozoan cysts, and helminth eggs present in drinking water to identify critical contamination sites. A total of 19 samples were processed to evaluate total coliforms and Escherichia coli using the multiple-tube fermentation method, and two samples were analyzed to detect intestinal parasites through basic microscopy. None of the samples met permissible limits established by NTE INEN 1108:2014 to be considered safe. Eight sites showed contamination >1600 MPN/100ml, both for total coliforms and E. coli. Eighteen resistant structures belonging to four genera of helminths and three cystic structures corresponding to three genera of protozoa were identified. Microbiological data were visualized through concentration mapping. It was concluded that drinking water in these communities is unsafe due to high levels of contamination. Therefore, it is recommended to: (i) implement treatment technologies, (ii) promote health education, (iii) protect water sources, and (iv) strengthen monitoring and institutional support to ensure access to safe water.