Heavy metals in Ethiopian drinking water and public health risks: Insights from nationwide and regional analysis

• Published in: The Science of the total environment Vol. 947; p. 174527
• Main Authors: Asefa, Elsai Mati, Damtew, Yohannes Tefera, Mengistu, Dechasa Adare, Tolera, Sina Temesgen, Dugasa, Faye Fekede, Berhanu, Abdi, Enoe, Jerry, Ober, Józef, Teklu, Berhan M., Weldemariam, Ermias Deribe
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.10.2024
• Subjects: Developing countries; Drinking Water - chemistry; Environmental Exposure - statistics & numerical data; Environmental Monitoring; Ethiopia; Humans; Meta-analysis; Metals, Heavy - analysis; Monte Carlo simulation; Non-carcinogenic risk; Probabilistic risk assessment; Public Health; Risk Assessment; Sustainable development goal; Water Pollutants, Chemical - analysis; Ethiopia; Developing countries; Probabilistic risk assessment; Non-carcinogenic risk; Sustainable development goal; Monte Carlo simulation; Meta-analysis
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.174527

The ambitious sustainable development goal (SDG) 6 of the United Nations, which aims to achieve universal access to safe water and sanitation by 2030, remains elusive for many developing countries like Ethiopia. This is often due to a multitude of intricate factors, including the escalating degradation of water quality. Here, we present a comprehensive nationwide and regional analysis of heavy metal pollution in drinking water sources and the associated human health risks in Ethiopia based on a dataset of 11 heavy metal concentrations (n = 975) collated from available studies. Results indicate significant variations in heavy metal pollution in drinking water sources in Ethiopia, with 44 % of the total concentration exceeding maximum permissible limits. The mean concentrations were ranked as follows: Pb (1.92 mg/L) > Zn (1.25 mg/L) > Fe (0.56 mg/L) > Mn (0.43 mg/L) > Cu (0.40 mg/L) > Co (0.30 mg/L) > As (0.12 mg/L) > Ni (0.12 mg/L) > Cr (0.10 mg/L) > Cd (0.06 mg/L) > Hg (0.04 mg/L). We found that children are more vulnerable to non-carcinogenic health risks than adults, with the highest hazard quotient (HQ) exceedances of up to a factor of 1823 and 762, respectively. Furthermore, a Monte Carlo-based probabilistic risk assessment highlighted significant concerns regarding co-exposure to multiple heavy metals. The measured concentrations, ingestion rates, and exposure frequencies were identified as sensitive parameters. Overall, a higher risk was attributed to Pb and As, with river drinking water sources and the Tigray region requiring immediate mitigation measures. In conclusion, the findings emphasize the urgent need to test and purify water before consumption and to implement effective public health interventions. Furthermore, a multifaceted approach including regular monitoring, source protection, and proper waste management is recommended to expedite the achievement of SDGs and promote water sustainability in resource-limited Ethiopia and sub-Saharan Africa. [Display omitted] •Approximately 44 % of the concentrations exceeded the drinking water guidelines.•For children and adults, 32 % and 19 % of the concentrations respectively posed significant health risks.•The major contributors to these risks were Pb, As, Cd, Hg, Cr, and Mn.•There was significant variation in the water sources, spatial, and temporal distribution.