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Groundwater quality assessment in Borana

of 69.01. Based on the calculated WQI values (Table 6), HCO₃⁻ (r = 0.666), EC (r = 0.976), TDS (r = 0.976),
the groundwater sources investigated were classified K⁺ (r = 0.892), Mg²⁺ (r = 0.912), Ca²⁺ (r = 0.962), SO₄²⁻
into three categories for drinking purposes: “Excellent”, (r = 0.963), and WQI (r = 0.975). These correlations
“Good”, and “Poor”. Accordingly, 20% of the Dubuluk indicate the mineralization of the investigated water
(D1 and D2) groundwater samples were rated as “Poor” samples. The results were also consistent with the
quality for intended human consumption. On the contrary, findings of Adamou et al. Strong correlations were
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30% of the Yabello (Y1, Y2, and Y4) sampling sites were observed between Mg²⁺ (r = 0.912), Ca²⁺ (r = 0.962),
found to have “Good” water quality. Conversely, 50% and SO₄²⁻ (r = 0.963), suggesting that the water samples
of the water samples collected from the present study, exhibit permanent hardness, likely caused by the presence
namely, those fetched from Yabello (Y3), Elewaye (E1 of magnesium and calcium sulfates. The WQI of the
and E2), and Surupa (S1 and S2), exhibited “Excellent” water samples exhibited significant positive correlations
water quality for human consumption. Notably, none of with several parameters, including NO₃⁻ (r = 0.651),
the water samples analyzed in this study were classified EC (r = 0.972), TDS (r = 0.972), K⁺ (r = 0.865), Mg²⁺
as “Very poor” or “Unsuitable for drinking” based on (r = 0.8502), Ca²⁺ (r = 0.964), TH (r = 0.975), and SO₄²⁻
the WQI values. In a related study conducted in the (r = 0.981), indicating their influence on overall water
Kombolcha town area of Ethiopia by Berhe, the WQI quality.
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values for groundwater samples ranged from 23.47 to
81.22, with an average of 42.14. Based on these values, 4. Conclusion
the groundwater was categorized into two groups:
excellent water and good water for drinking. In addition, This study aimed to assess groundwater quality for
findings by Mengstie et al. indicated that WQI analysis drinking using indices such as GPI, NPI, and WQI.
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classified the water samples from the source, reservoir, All groundwater samples analyzed exhibited turbidity,
and taps in Hawassa town, Ethiopia, as being of good pH, HCO₃⁻, NO₂⁻, and Cu²⁺ concentrations within or
quality for drinking purposes. below the threshold values set by the WHO. However,
some parameters exceeded the recommended limits.
3.5. Correlation coefficient matrix analysis All groundwater sources investigated were classified as
As reported by Sanad et al., a correlation coefficient (r) hard water.
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close to +1 or −1 indicates a strong positive or negative The GPI values ranged from 0.190 to 1.44, with the
correlation, respectively, between two variables. majority (80%) of the ground drinking water sources
The results of the Pearson correlation matrix (r), categorized as “Insignificant pollution” (GPI < 1),
obtained from the statistical analysis of 20 selected indicating their suitability for human consumption. In
variables, are presented in Table 7, with bolded contrast, 20% of the sources were classified as having
coefficients indicating very strong correlations. “Low pollution” (1 < GPI < 1.5). The NPI values ranged
In this study, the water temperature showed a from −0.89 to 4.04, with 50% of the groundwater
significant positive correlation only with K⁺ (r = 0.699). drinking source classified as “Clean (unpolluted)”.
Meanwhile, turbidity exhibited a significant positive Three sources (30%) were classified as experiencing
correlation only with total Fe (r = 0.766). In addition, “Moderate pollution”. The D2 groundwater drinking
TDS and EC demonstrated a perfect positive correlation source was categorized as “Low pollution”. Notably,
(r = 1). It is important to note that TDS and EC are the Y1 groundwater drinking source was identified
closely related and can often be used interchangeably. 16 as experiencing “Very high pollution”, indicating a
Variations in TDS as a function of HCO₃⁻, TA, K⁺, significant and concerning level of nitrate contamination
Mg²⁺, Ca²⁺, TH, SO₄²⁻, and the WQI exhibited strong likely linked to anthropogenic activities, such as
positive associations, with r values ranging from 0.720 fertilizer use and sewage intrusion. The WQI analysis
to 0.976. The pH of the water samples showed a positive revealed that 50% of the groundwater sources are
significant correlation only with Cr (r = 0.801). classified as “Excellent” quality for drinking, while 30%
6+
Furthermore, HCO₃⁻ demonstrated significant are rated as “Very good” and 20% as “Good” quality
positive correlations with several parameters, including for human consumption. The findings of this study
K⁺ (r = 0.814), Mg²⁺ (r = 0.652), TH (r = 0.666), provide valuable insights for policymakers and relevant
EC (r = 0.720), and TDS (r = 0.720). TA showed a authorities, supporting informed decision-making and
perfect positive correlation with HCO₃⁻ levels (r = 1). effective management strategies.
TH displayed a strong positive correlation with

Volume 22 Issue 1 (2025) 111 doi: 10.36922/AJWEP025040023