Physicochemical analysis of tap water in Tepi town, Southwest Ethiopia

Physicochemical analysis of tap water was carried out in Tepi town southwest Ethiopia. After digestion with microwave acid digestion, some selected metals (Mg, Ca, Cu, Mn, Fe, Zn, Cd &Pb) were determined using Flame Atomic Absorption Spectrophotometer and some selected common anions were determined as follows, Ortho phosphorous (PO4-3) by APHA4500-PC.Vanadomolybdphosphoric method, Chloride (Cl-) by APHA4500-Cl-B. Argentometric method, Carbonate (CO3-2) by APHA 2330B. Titration, Nitrate (NO3-) and ammonia (NH3) by WTD photometer method (WAG PHOT-24). The mean temperature of all water samples were ranged between 24.50 + 0.38 OC to 27.50 + 0.60 OC, which was found above the European Commission (EC) standards (12- 25°C) set for waters used for drinking purpose. The pH of water samples were lied from 6.62+0.06 to 7.89+0.10. Which was within the prescribed recommended limits of WHO guideline. The Conductivity (EC) values of all water samples were ranged between 87.8+0.47- 313.5+0.6 µs/100ml. When compared to WHO standard, the analyzed results were within the maximum admissible limit that allow to consume water with EC up to 250 μS/cm. The total hardness value of all water samples were found above the recommended value, which ranged from 685+1.76 mg/L to 792+1.84 mg/L. These selected major, minor-essential metals were present in the water samples. From the toxic metals Pb was not detected in all water samples but Cd was detected in distribution points (reservoirs) but not on the distribution systems (households) of the study area. The concentration of Mg (246.8 + 0.002 ppm) was higher followed by Ca (8.581+ 0.013ppm) in water samples. The levels of minor – essential metals in this sample, Fe (6.521 + 0.001 ppm) was higher followed by Mn (6.41 + 0.001 ppm), Zn (1.354 + 0.009 ppm) and Cu (0.162 + 10-5 ppm) respectively. Cd was detected in water samples of reservoirs with a maximum concentration (0.045 + 0.005) and the concentration of Pb was below the method detection limit in all the water samples. According to WHO guidelines the rage of these selected metal ions were on safe side except Cd. Under this investigation, at p = 0.05, the physicochemical parameters of all water samples which were taken from different sites were significantly different among the distribution points distribution systems.