Assefa Fassil (PhD)Mengistuo Seyoum (PhD)Tassew Admasu2018-06-132023-11-092018-06-132023-11-092007-07http://etd.aau.edu.et/handle/123456789/787The level of water pollution and ecological disturbance of Sebeta River was evaluated using some important physico-chemical and biological parameters. The Physico-chemical parameters were: flow velocity (m/s), dissolved oxygen (DO) (mg/L), pH, temperature (0c), electrical conductivity (EC) (μs/cm), nitrate-nitrogen (mg/L) and phosphate (mg/L). The mean flow velocity and nitrate-nitrogen measures showed no significant difference between the study sites of Sebeta River (P > 0.05). DO records of the river at the upstream rural sites above Sebeta Agro-industry (SR1 and SR2) were significantly higher than the DO records of the downstream sites (P < 0.001). The mean pH values of SR3 (3.60 ± 0.81) (immediately downstream from Bale Zaf Alcohol and Liquor Factory and Soap Factory) and SR4 (4.75 ± 0.88) (downstream of National Alcohol and Liquor Factory and Blue Nile Tannery) were significantly lower than the pH values of the rest of the sample sites (P < 0.001). The mean temperature and EC records of SR3 (33.83 ± 1.17 0c, 16050.00 ± 2270.77 μs/cm) and SR4 (27.63 ± 0.68 0c, 15400.00 ± 316.60 μs/cm) were significantly higher than the respective records at the rest of the study sites (P < 0.001). Phosphate concentration at SR3 (8.59 ± 1.16 mg/L) was significantly higher than the phosphate concentrations recorded from the other sites (P < 0.001). Flow velocity and nitrate-nitrogen of Sebeta River were in the natural range, except for extreme values at sites SR3 and SR4. Habitat integrity assessment was done according to the US Environmental Protection Agency Rapid Bioassessment Protocol. Percent comparability of habitat scores classified the upstream reference sites to good, while it categorized the entire downstream sites to very poor. The mean chlorophyll ‘a’ measures of upstream reference sites (SR1 and SR2) showed significantly higher values than those of the impacted downstream sites (P < 0.001). Macroinvertebrate community index of Sebeta River (MCISR) was developed using selected metrics. The MCISR score classified both of the upstream sites (SR1 and SR2) to very good biological integrity, while it classified all the downsteam sites to very poor biological integrity, but SR8 (further down in Atebela peasants association) to poor.enBiologyThesis