Assessment of industrial effluent pollution on Borkena River, Kombolcha, Ethiopia

Abstract

In this study the effect of untreated and partially treated industrial wastewater on Borkena River was assessed. Six sampling sites were chosen spatially along the tributary of Borekena River and the River itself. The results indicated significant water quality deterioration, which characterized by Temperature, TSS, TDS, DO, BOD5, COD and Phosphate with the mean concentration range from 45.27 ± 6.0 to 302.00 ± 10.56 °C, 571.67 ± 94.34 to 1633.33 ± 175.46, 450.00 ± 30 to 2422.33 ± 431.2, 6.40 ± 0.61 to 2.77 ± 0.35, 10 ± 0.50 to 190 ± 1.01, 34 ± 3.00 to 508 ± 4.00 and 12.93 ± 4.41_329.33 ± 43.03 mg/L respectively. The magnitude of these values were found above the permissible limits of ambient surface water quality stated by Ethiopia Environmental Protection Authority at all sampling sites, except upstream of Borkena River (SP_6). Significant increment of these parameters was evidenced at the downstream (SP_5) in comparison with the upstream (SP_6) of Borkena river (P < 0.05). The mean concentration of pH, EC, Sulphate, and Nitrate nitrogen were ranged from 6.84 ± 0.35 to 9.75 ± 0.43, 0.92 ± 0.27 to 9.07 ± 0.43, 7 ± 5.20 to 59.67 ± 11.52 and 3.57 ± 0.16 to 28.68 ± 4.91 mg/L were found under the permissible limits, except pH at sampling point 1 and 3. It was therefore concluded that Huaxu textile and BGI-brewery industry’s effluents are polluted, from which Huaxu textile industry’s effluent was contributed more for Borkena River contamination.