RESUMEN
Water quality issues in Ethiopia necessitate the implementation of the Water Safety Plan (WSP) to safeguard drinking water. Despite its benefits, WSP implementation is underutilized, a situation exacerbated by urbanization, agriculture, pollution, and climate change. This study evaluated water supply system vulnerability and delineated protection zones in the Upper Awash River subbasin. By employing the DRASTIC model, the National WASH Inventory-2 (NWI-2), and qualitative methods, this research aims to integrate the NWI-2 with vulnerability assessments. The study revealed that, among 2864 schemes, only 14.4% had a water safety plan, while 20.7% practiced water safety, and 6% reported the occurrence of waterborne diseases. Over 39.23% of the schemes were in high vulnerability areas, 12.32% were in very high vulnerability areas, and only 8% were in low vulnerability areas. The validation revealed a 61.7% association between the vulnerability indices and nitrate concentration. The strengths of the strategy included coordination and guideline development, but challenges such as institutionalization, catchment protection, the legal framework, and climate information remain for the Water Safety Plan. To promote public health, these findings help to demonstrate and integrate the NWI-2 with vulnerability assessments to protect drinking water sources. The conclusion also calls for all concerned authorities to implement water source protection, emphasizing the use of GIS technology and the adoption of integrated watershed management practices, which encompass regulatory control and conservation strategies. Furthermore, more research on the pollutant time of travel, assimilation capacity, and land use priorities is needed to delineate specific protection zones.
RESUMEN
The Upper Awash sub-basin characterized by urban, industrial, agricultural and population growth, has impacted the quality of its water sources. This study focuses on the assessment of public health risks associated with drinking water sources in the sub-basin. In accordance with WHO guidelines, 120 water samples were collected from 60 water supply schemes in dry and wet seasons located in areas with low and high water pollution risk (WPR). Multi-meter, Photometer, Digital Arsenator, and Microbiological test kit measured the concentration of parameters. The assessment uses methods of hazard identification, exposure and dose-response analysis, and risk characterization, including Hazard Quotient (HQ), Cancer Risk (CR), Hazard Index (HI), and probability of infection. Monte Carlo simulation analyzes non-cancer risks from Nitrite, Nitrate, Chromium, Iron, Fluoride, and Arsenic, and CRs from Chromium and Arsenic, and infection risks from Escherichia coli (E.coli). As a result, the Hazard Quotient (HQ) of Nitrate was beyond unity (HQ > 1) in the dry season for all groups. HQ of Chromium was HQ > 1 for Women (1.1E+00) and Children (1.4E+00) in the wet season in the high WPR area. Chromium HQ > 1 for children (1.4E+00) in the wet season and Fluoride (HQ > 1) for Children (3.2E+00) in the dry season in the low WPR area. Arsenic CR was above 1 in 10,000 persons for children in the dry season, for all groups, and for women and children in the wet season in the high WPR areas. The CR of chromium ranged from 1 in 1000 persons, which is beyond the limit. Moreover, the Hazard Index (HI) was higher than the unity (HI > 1) for most cases. All E coli infection risks daily and annually exceeded the acceptable risks. Therefore, Public health concerns in the Sub-basin were quantified, and evidences were generated for risk management to undertake source protection through integrated watershed management and appropriate water treatment technologies.
