Physicochemical and Biological Parameters of Domestic Tap Water of Nedjo Town from Source to Households, Ethiopia

Abstract

Poor quality of drinking water is one of the major causes of waterborne diseases in Ethiopia. A cross-sectional study was conducted to evaluate the physicochemical and bacteriological properties of Nejo town drinking water from sources, reservoirs, and distribution systems (household taps) from January to August 2020. A total of 117 samples were taken from eight sampling sites: three treatment points, one reservoir, and four Kebeles through the watercourse during the dry and rainy seasons. The water samples were determined for pH, temperature (TO), electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), turbidity, Fe⁺², Mn⁺² NO^3-, SO4^-2, PO4^-3, F^-, Cl^-, total hardness (TH), total coliforms (TC), and faecal coliforms (FC). The parameters showed significant variation based on sampling point and sampling time, except pH, TO EC, and TDS. There was a negative correlation between TC and chemical parameters except for Fe⁺² andTH at α = 0.05. The number of TC in the water samples ranges from 3–31CFU/100 mL, but there are no faecal coliforms. The pH, TO, and EC of thewater ranged from 6.66–8.13, 11.53–17.6 ºC, and 218–393 µS/cm,respectively, which was to the standard of the WHO. Similarly, the maximum concentration (mg/L) of Fe⁺², Mn⁺², NO₃^-, SO₄^2-, and PO₄^3- was 0.22, 1.24, 38,3.6, and 0.86, respectively, which qualifies the standard set by WHO and the national drinking water minimum requirement except NO₃^- . However, total dissolved solids and turbidity ranged from 62.73–154 mg/L and 4.23 NTU, respectively, which require further treatment to fit into the minimum national standard. Depending on the tested parameters at the time, Nedjo town drinking water has negligible health risks, although continual testing is mandatory, including other parameters.