Abstract:
The present study has undertaken to assess the water quality as well potential source of contamination of Awash River by considering effluent discharged from Anmol paper factory. In the study, three sampling sites along the river course have chosen based on the objectives of the study and potential source of pollution. The levels of heavy metals were determined by use of FAAS and data analysis was achieved by use of ANOVA. The instruments have calibrated using distilled water and standard solution by following standard procedures. The observed mean values of the physicochemical analysis were in the range of 24.8±0.00-26.1± 0.00°C, 11.05±1.29-49.23±0.4 NTU, 297±1-472.33±4.04 μS/cm, 194.67±1.53-734.67±0.58 mg/l, 6.8±0.1-7.05±0.13, 3.57±0.04-4.45±0.04 mg/l, 173±7-459.33 mg/l, 53.4±7.03-177.21±3.00 mg/l, 10.14±2.51-795.65±8.70 mg/l, 19.42±1.13-88.83±3.82 mg/l, 5.37±0.31-16.37±0.61 mg/l, 10.11±8.09-36.13±2.97 mg/l, 54.18±10.45-124.2±2.42 mg/l for temperature, turbidity, conductivity, total dissolved solid, pH, DO, total hardness, chloride, sulphate, sodium, potassium, magnesium, calcium, respectively. The concentrations of heavy metals (mg/l) in the water samples were found within the range of 2.07±0.12-3.67±1.53, 0.11±0.01-1.45±0.04, 1.25±0.15-2.27±0.22, 0.55±0.02-0.62±0.03, 0.88±0.03-3.71±0.03 for Ni, Mn, Cu, Zn and Fe, respectively. The heavy metals including Pb, Co, and Cd were not detected. The water quality was acceptable at upstream (site A) of the river. Site B (effluent discharge site from Anmol paper factory) recorded higher values in E.C (472.33±4.04 μS/cm), TDS (734.67±0.58 mg/L), TH (459.33±6.11 mg/L), pH (7.05±0.13), Mg (36.13±2.97 mg/L), Ca (124±2.42 mg/L), Cl-(177.21±3.00 mg/L), DO (3.57±0.041 mg/L), K (16.37±0.61 mg/L), Na (88.83±3.82 mg/L), Ni (3.67±1.53 mg/L), Mn (1.45±0.04 mg/L) and Zn (0.62±0.03 mg/L). Site B to be the most polluted site, probably being the point of discharge. The obtained values of each parameter were compared with the standard values set by Ethiopia EPA (2003) for surface water quality standards and Ayres and West cot, FAO (1994) for domestic use, drinking cattle and irrigation water. The concentrations of each parameter (except, EC and pH) among the selected sites were significantly different (ANOVA, p≤0.05). These findings indicate that, there is a need to protect the quality of the river water. Therefore, this study recommends that the government and other responsible authorities have to take appropriate corrective action to reduce source of the contaminants of the river water
