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Groundwater quality assessment in Borana

The mean pH values of the water samples from the primarily attributed to HCO₃⁻ ions, was the dominant
study area ranged from 6.25 to 8.11. The majority of form of alkalinity observed in the water samples, as all
the samples (60%, n = 10) fell within the recommended measured pH values were below 8.3 (Table 5).
pH range of 6.50 – 8.50 as established by the WHO.
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However, 40% of the samples had pH values below the 3.1.5. Ca and Mg levels
2+
2+
recommended lower limit of 6.50. Notably, almost all Elevated levels of Ca²⁺ can lead to abdominal issues
the samples (90%) exhibited acidic pH levels, with the and are undesirable for domestic use, as they contribute
exception of one sample (10%) from the E1 sampling to encrustation and scaling. The mean concentrations
38
site, which was slightly basic (pH = 8.11) (Table 5). of Mg²⁺ and Ca²⁺ in the water samples were 4.80 –
79.2 mg/L and 22.2 – 284 mg/L, respectively (Table 5).
3.1.2. Turbidity The mean concentrations of Ca²⁺ and Mg²⁺ at the D1
The turbidity values of the water samples ranged from sampling site were 3.79 and 1.58 times higher than the
0 to 4 NTU. Of the ten samples analyzed, four (40%) standards set by the ESA and the WHO, which are
36
33
had turbidity values >0 NTU. However, all samples 75 mg/L and 50 mg/L, respectively. Similarly, at the D2
remained below the maximum allowable turbidity level sampling site, the mean concentrations of Ca²⁺ and Mg²⁺
of 5 NTU, as recommended by the WHO. 34 were 2.93 and 1.49 times higher than the recommended
values.
3.1.3. TDS
The water samples analyzed in this study exhibited 3.1.6. TH
TDS concentrations ranging from 99.0 to 1930.0 mg/L The water samples analyzed showed TH values ranging
(Table 5). Notably, except for two samples (20% of the from 96.00 to 1040.00 mg/L as CaCO . According
3
total, n = 10) collected from the D1 and D2 sampling to the WHO, the maximum permissible limit for
34
sites, all other samples had TDS concentrations below TH in drinking water is 300 mg/L as CaCO₃. Sixty
the public acceptability threshold of 1000 mg/L percent of the water samples, including those from the
recommended by the WHO. Based on these TDS Y1, Y2, Y4, E2, D1, and D2 sampling sites, had TH
34
values and the palatability ratings for drinking water concentrations ranging from 1.05 to 3.47 times higher
provided by the WHO, the groundwater sources than the maximum tolerable limit set by the WHO.
34
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in the study area were categorized as follows: Two These sources, therefore, require treatment as they are
sources (20%) (Y3 and S2) were classified as excellent not suitable for human consumption. In contrast, 40%
for potable use, while four sources (40%) (Y2, E1, of the samples, specifically those from the Y3, E1, S1,
E2, and S1) were rated as good for drinking; two and S2 sites, met the WHO standards for drinking
34
sources (20%) (Y1 and Y4) were considered fair for water TH levels. Based on the laboratory test results and
human consumption, and the remaining two sources the TH classification method used by the WHO, the
33
(D1 and D2) were classified as unacceptable for investigated groundwater sources were categorized as
human consumption and require close monitoring. follows: Seven sources (70%) – Y1, Y2, Y4, E2, S1, D1,
The elevated TDS values observed in certain samples, and D2 – were classified as very hard water; one source
particularly from the D1 and D2 sites, may be attributed (10%) – Y3 – was classified as moderately hard; and
to natural interactions between rocks and water sources two sources (20%) – E1 and S2 – were classified as hard
in the area, as noted by Berhe. This interaction can water. Consequently, all of the investigated groundwater
12
lead to the dissolution of minerals and the subsequent sources in the research area were considered to be
release of dissolved solids into the water, increasing hard water. Water hardness is primarily related to the
the TDS concentrations. concentrations of Ca²⁺ and Mg²⁺. 16,39 As a result, all
water samples with elevated levels of Ca²⁺ and Mg²⁺
3.1.4. TA exhibited correspondingly high TH values.
The TA concentrations in the water samples ranged
from 110 to 360 mg/L (Table 5). The Ethiopian 3.1.7. K levels
+
Standards Agency recommends that TA should not Increased potassium levels in drinking water, as
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exceed 200 mg/L in drinking water. Of the ten water highlighted by Gintamo et al., can contribute to
24
samples analyzed, four (40%) – E1, E2, D1, and D2 neurological and digestive issues.
sampling sites – had TA values that exceeded this The measured concentrations of K⁺ in the water
maximum permissible limit. Bicarbonate alkalinity, samples ranged from 1.2 to 46.25 mg/L (Table 5). The

Volume 22 Issue 1 (2025) 107 doi: 10.36922/AJWEP025040023