Sanitary Inspections as a Risk Assessment in Predicting Faecal Contamination of Rural Drinking Well Water in Central Highland of Ethiopia

Abstract

Access to safe drinking water is one of the basic human rights and is critical to health. However, approximately 900 people in the world still do not get their drinking water from safe sources where the sub-Saharan Africa accounts for over one third of this number. It is estimated that 80% of all illnesses in the world are related to use of unsafe and contaminated water. A longitudinal study was conducted from August 2022 to February 2023 in three selected Ambo, Toke Kutaye and Jibat woredas (districts) of central highland of Ethiopia. Water samples were collected once a month for three consecutive months in both wet and dry seasons, and examined for E.coli and Enterococci CFU/100ml to investigate the sanitary inspection as a risk assessment tool by estimating the microbial load of Faecal Indicator Bacteria (FIB) and selected physicochemical parameter; Water Temperature (WT), potential of Hydrogen ion (pH), Dissolved Oxygen (DO), Electrical conductivity (EC), available total phosphorus (P), nitrite (NO2 - ) and nitrate (NO3 - ). The risk of watersources were assessed using the sanitary inspection checklist adopted from the World Health Organization (WHO). For this investigation, a total of 78 water samples from 13 Dug-wells were collected. The results were interpreted using WHO guideline and Compulsory Ethiopian Standard (CES for drinking water quality. A total of 78 drinking water samples showed contamination with Escherichia coli and only two samples were negative for Enterococci. Nitrate and Nitrite concentration ion of all samples were below the WHO and ESA's permitted level for drinking water use. Based on WHO criteria, 61% of water sources were grouped into high and very high risk. Drainage faulty, drainage channel crack and absence of plat (the concrete floor) with trunk were significantly associated with water contamination rate. Our findings suggest that most water sources in the studied woreda’s of Western Shewa Zone, Oromia Region are contaminated by faecal coliforms. Therefore, regular sanitary inspection, bacteriological analysis, well constructed drainage channels and trunk are advocated to protect drinking water sources from faecal contamination.