Assessment of Water Quality and Associated Health Risks near Addis Ababa Repi Open Dumping Site in Ethiopia

Abstract

Open dumping remains a common urban waste disposal method in developing nations, including Ethiopia. The Addis Ababa Repi dumping site operates without liner or leachate management, posing risks to surrounding water resources. This study assessed water quality in five groundwater wells (GW1-GW5) and six Jemo River locations (SW1-SW6) during the rainy season (August, 2024). A leachate sample was collected from the site. Parameters used to analyze included pH, turbidity, TDS, nitrate, cyanide, total coliforms, and fecal coliform bacteria. Non-carcinogenic health risks from NO₃⁻ were assessed using the Hazard Quotient (HQ). Health risks from CN⁻ and microbial contamination were discussed qualitatively based on drinking water standards. Leachate from Repi showed severe contamination: pH 8.8, turbidity 550 NTU, TDS 15,900 mg/L, NO₃⁻ 38.7 mg/L, CN⁻ 0.504 mg/L, TCB 5,100 CFU/100 mL, and FCB 220 CFU/100 mL. Groundwater chemical parameters were within drinking standards. However, GW1 and GW2 (southeast, down gradient) showed fecal contamination (1 CFU/100 mL) exceeding the standard, suggesting possible leachate influence. River water exhibited severe degradation downstream of the dumpsite. Turbidity (48-172 NTU) and TDS (1,401-1,983 mg/L) were used to classify the river water as unacceptable for drinking but useful for irrigation. All river samples showed fecal coliform counts (33-110 CFU/100 mL) far above permissible limits. Downstream site SW6 showed the highest FCB (110 CFU/100 mL) and CN⁻ (0.143), while upstream sites SW1 and SW2 had elevated CN⁻ (0.396-0.197 mg/L) from community and industrial wastes, indicating multiple pollution sources. HQ values for NO₃⁻ were < 1 for all samples, indicating negligible health risk. This study recommends water quality monitoring and remediation near open dumping sites in urban Ethiopia. Keywords: Dumping Site, Groundwater, Health Risks, Microbial Contamination, River Water