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Asian Journal of Water, Environment and Pollution. Vol. 22, No. 1 (2025), pp. 99-114.
doi: 10.36922/AJWEP025040023

ORIGINAL RESEARCH ARTICLE

Assessment of groundwater quality in Borana Zone,
Ethiopia: A multidimensional analysis using groundwater

pollution index, nitrate pollution index, and water quality

index

Dereje Diriba * and Daniel Fitamo 3
1,2
1 Department of Environmental Science, College of Natural and Computational Sciences, Bule Hora University, Bule Hora,
Ethiopia
2 Department of Chemistry, College of Natural and Computational Sciences, Dilla University, Dilla, Ethiopia
3 Department of Biology, College of Natural and Computational Sciences, Hawassa University, Hawassa, Ethiopia
*Corresponding author: Dereje Diriba (Dereje.diriba@du.edu.et)

Received: January 23, 2025; Revised: February 26, 2025; Accepted: February 27, 2025; Published Online: March 14, 2025

Abstract: This study assessed groundwater quality in Yabelo, Elewaye, Gomole, and Duduluk towns in Ethiopia,
analyzing 60 samples across 19 physicochemical parameters. The groundwater pollution index (GPI), nitrate
pollution index (NPI), and water quality index (WQI) were used to evaluate drinking water suitability. Results showed
turbidity, pH, bicarbonate, nitrite, and copper levels were within the World Health Organization recommended
limits. However, 20% of the samples had high total dissolved solids and sulfate levels. Total hardness exceeded
limits in 60% of the samples, and 40% had elevated nitrate concentrations. Chromium and fluoride were elevated
by 10%, while total iron and manganese exceeded standards by 20%. The GPI indicated “Insignificant pollution”
in 80% of samples and “Low pollution” in 20%. Among the samples, the NPI classified 50% as “Clean”, 10% as
“Low pollution”, 30% as “Moderate”, and 10% as “Very high pollution”. The WQI rated 20% as “Good”, 30%
as “Very good”, and 50% as “Excellent”. This study provides valuable insights to help authorities in identifying
protective measures and treatment methods for water resources.

Keywords: Borana Zone; Drinking water; Ethiopia, Groundwater; Groundwater pollution index; Nitrate pollution
index; Physicochemical parameter; Water quality index

1. Introduction and groundwater for human use. In both urban and
4
rural areas worldwide, groundwater serves as a crucial
Water is essential for life; without it, existence is source of water for household consumption. Water
5
impossible. Groundwater is becoming an increasingly contamination can result from both anthropogenic
1
vital source of drinking water worldwide, as surface sources, such as industrial activities, agricultural
water is increasingly affected by pollution and climate practices, improper waste disposal, and inadequate
change. It is estimated that only 3% of Earth’s water is sewage systems, as well as natural sources, including
2,3
freshwater, with 2.97% of this being locked in ice caps microbial activity, geological factors, and naturally
and glaciers, leaving only 0.03% available as surface occurring contaminants. To ensure water is safe
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Volume 22 Issue 1 (2025) 99 doi: 10.36922/AJWEP025040023