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Diriba and Fitamo

maximum permissible limits for K⁺ in drinking water The recorded NO₂⁻ concentrations ranged from
are 1.5 mg/L and 12 mg/L, according to the ESA 0.003 to 0.009 mg/L (Table 5). All tested water samples
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and WHO, respectively. Among the ten groundwater had NO₂⁻ concentrations significantly below the health
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sources investigated, only one sample (10%) from the standard value of 3 mg/L, as recommended by both the
Y3 sampling site had a K⁺ concentration (0.9 mg/L) ESA and the WHO. These findings are consistent with
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below the maximum permissible limits set by both those of Berhe, who reported that NO₂⁻concentrations
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ESA and WHO. The remaining 90% of the samples in water from various locations in Kombolcha town,
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had K⁺ concentrations that were 2.4 – 30.8 times higher Ethiopia, were within the recommended limits.
than the standards suggested by the ESA. Except for
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the sample from the Y3 site, the K⁺ concentrations 3.1.10. F⁻ levels
measured in all other samples were higher than those The F⁻ concentrations in the drinking water samples
reported in other regions of Ethiopia. 12,40 The elevated K⁺ from the present study ranged from 0.32 to 2.52 mg/L,
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concentrations observed in the water samples from the as shown in Table 5. The WHO and the ESA
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D1 (46.25 mg/L) and D2 (38.75 mg/L) sampling sites recommend a maximum permissible limit of 1.5 mg/L
could be attributed to localized chemical weathering of for F⁻ in drinking water. Concentrations exceeding this
potash feldspars, as noted by Dawit et al. 40 threshold increase the risk of dental fluorosis, and higher
levels further elevate the risk of skeletal fluorosis.
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3.1.8. SO₄²⁻ levels Nearly 90% (n = 10) of the analyzed water samples
High levels of SO₄²⁻ in drinking water may induce a had F⁻ concentrations below the recommended limit of
laxative effect. The measured concentrations of SO₄²⁻ 1.5 mg/L. However, one sample from the E1 sampling site
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in the water samples ranged from 2.5 to 360 mg/L. recorded an F⁻ concentration of 2.52 mg/L, surpassing
Of the ten water samples analyzed, eight (80%) had the limit. Similar studies in Ethiopia by Mengstie et al.
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SO₄²⁻ concentrations within the public acceptability and Garoma et al. reported F⁻ concentrations in water
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guideline value of 250 mg/L, as recommended by the samples that were consistent with the 90% compliance
WHO. However, two samples (20%) from the D1 observed in the present study. In contrast, the results of
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and D2 sampling sites exceeded this guideline, with the present study differ from those of Amanial, who
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concentrations of 360 mg/L and 325 mg/L, respectively. reported F⁻ concentrations in spring water samples
The elevated levels of SO₄²⁻ in the water samples from from Arba Minch town, Ethiopia, ranging from 2.048 to
the D1 and D2 sites may be attributed to the presence 4.415 mg/L, significantly exceeding the standard limit.
of sulfate-containing minerals, such as gypsum or
anhydrous calcium sulfate, which can dissolve in water 3.1.11. Cu²⁺ levels
and increase sulfate ion concentrations, as noted by In the present study, the analyzed water samples
Gebresilasie et al. The results for SO₄²⁻in this study exhibited varying concentrations of Cu²⁺, ranging
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were consistent with the findings of Gebresilasie et al. from 0.05 to 0.69 mg/L (Table 5). Notably, the Cu²⁺
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and Abegaz and Midekssa. However, they were concentrations in these samples were significantly
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inconsistent with the findings of Adamou et al. 16 lower, approximately 2.9 – 40 times below the health-
based guideline value of 2.0 mg/L, as recommended
3.1.9. NO₃⁻ and NO₂⁻ levels by both the WHO and the ESA for drinking water.
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Elevated levels of NO₃⁻ and NO₂⁻in drinking water can These results are consistent with the findings of Berhe
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lead to “blue baby” syndrome (methemoglobinemia). 25,34 and Lewoyehu, who reported that Cu²⁺ concentrations
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The concentrations of NO₃⁻ in the water samples ranged in water samples from Kombolcha Town and the Mecha
from 2.2 to 100.8 mg/L (Table 5). The health-based District, Ethiopia, were also below the recommended
guidelines for NO₃⁻ in drinking water, as recommended limit.
by both the ESA and the WHO, is 50 mg/L. Among
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the ten water samples analyzed, six (60%) – Y3, S1, S2, 3.1.12. Cr⁶⁺ levels
E1, E2, and D2 sampling sites – had NO₃⁻concentrations According to the data presented in Table 5, the
that were 0.74 – 22.73 times lower than the health-based concentration of Cr⁶⁺ in the analyzed water samples
guideline values. These findings align with previous ranged from 0.01 to 0.06 mg/L. Remarkably, almost
studies 5,12,25,39,42,43 conducted in Ethiopia, all of which all (90%, n = 10) of the water samples exhibited Cr⁶⁺
reported NO₃⁻concentrations within the prescribed limit concentrations that were 1.92 – 6.25 times lower than
of 50 mg/L. the WHO recommended provisional guideline value
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Volume 22 Issue 1 (2025) 108 doi: 10.36922/AJWEP025040023