EVALUATIONOFPHYSICOCHEMICAL PROPERTIES AND DETERMINATION OFTHE LEVELES OF HEAVY METALS IN BOREHOLE DRINKING WATER IN GONDAR CITY, ETHIOPIA

Abstract

The sources of physicochemical and heavy metal contamination in groundwater are numerous and could have major consequences for human health. The study was done to evaluate the physicochemical parameters and concentrations of heavy metals in borehole water found in Gondar city. Six borehole groundwater samples (UOG (Qun and Vet), Cha, Dash, Yo, and Shew) were randomly selected and collected from each sampling location, then tested for key physicochemical parameters and heavy metal levels using conventional analytical procedures. The values obtained for the six tested samples were: the temperature ( 27.43±0.06 to32.5±0.1 )C0, the pH ranged from (8.05±0.02 to 9.05±0.03), the conductivity ( 326.33 ±2.08 to 1236.67±1.53 µS), DO also ( 5.80 ±0.04 to 6.97± 0.02 mg/L), the TDS (208.33±1.53 to 647.33±2.08 ppm), salinity (0.09 ±0.01 to 0.56 ±0.02 ppt), Turbidity (2.179±0.077 to 4.603 ±0.0644 NTU), Hardness ( 96 ±1 to 232 ±2 mg/L) and BOD5 (4.11 ±2.965 t0 5.008 ±2.781 )., The concentration of heavy metals found in the ground water samples were in the ranges of; Fe (0.938± 0.073 to 4.125± 0.174 mg/L), Cu (1.03 ± 0.05 to6.13 ± 0.32 mg/L), Zn (1.923 ±0.100 to 6.828 ± 0.396 mg/L ), Mn (0.773 ± 0.0470 to 0.780 ± 0.0381 mg/L ), Ni ( 0.5± 0.026 to3.522±0.1301 mg/L ), and Pb ( 0.046 ± 0.001 to 3.298 ± 0.445 mg/L). The average values of physicochemical properties and heavy metals for all the borehole drinking water were within the maximum permissible limits (MPL)specified by the World Health Organization and Environmental Protection Agency, except for zinc, lead, and iron levels. Generally, the water quality of the six borehole ground water samples was good in the case of all the studied physicochemical parameters; however, there may be an adverse effect due to the consumption of the water with six levels of Zn, Pb & Fe. This assessment of some physicochemical and heavy metal quality of water is necessary but not sufficient to determine its suitability for drinking purposes. It is recommended that the boreholes be treated adequately to avoid possible health and other consequences of using the water from these wells. *Key words: Borehole water, Drinking water, physicochemical parameters, and concentration of heavy metals