IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) e-ISSN: 2319-2402,p- ISSN: 2319-2399.Volume 14, Issue 5 Ser. III (May 2020), PP 01-09 www.iosrjournals.org DOI: 10.9790/2402-1405030109 www.iosrjournals.org 1 | Page Effect of Effluents on Fish and Water Quality from Selected Tributaries of Ureje Reservoir in Ado-Ekiti. 1 Adebayo I. A and 2 Familusi, O. A 1,2 Department of Fisheries and Aquaculture Management, Faculty of Agricultural Sciences, Ekiti State University, Ado Ekiti, Ekiti State, Nigeria. Abstract: The impact of effluents on water and fish quality in some Nigerian waters is alarming due to indiscriminate dumping of domestic and industrial wastes into the waters. Ureje reservoir and its tributaries are no exception to this menace; hence the need to examine the effect of unrestricted dumping of refuse into the reservoir on fish and water quality. Four sampling stations (A-D) were selected namely: A (Upstream tributary) along Busy Minds International School; B (Downstream tributary) along Aba Igbira settlement; C (Tributary close to the middle of the reservoir) along Sije road and D (the main reservoir) respectively. Site selection was based on the high volume of water contribution to the main reservoir and proximity to refuse dump site. Water and fish Samples were collected for Laboratory Analysis using Standard Methods. Results obtained were subjected to one-way analysis of variance using Statistical Package for Social Sciences. Results of water analysis showed the values of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) to be significantly (p<0.05) highest (272.67mg/l O 2 and 340 mg/l) respectively in sampling station C, denoting it as the highest point of effluents influx. The values for Iron (Fe) were significantly (p<0.05) high than the maximum permissible limits to man in all the sampling stations with the highest value (12.30mg/l) in station B indicating highest mineral deposits. The highest Values of alkalinity (182.67mg/lCaCO 3 ); acidity (304.85mg/lCaCO 3 ); phosphates (0.04mg/l) and chloride ( 11.70mg/l) were recorded in the main reservoir (Station D), showing highest ionic exchange due to much aquatic activities. The microbiological analysis showed Water Total Bacterial Count (WTBC) and Fish Total Bacterial Count (FTBC) to be significantly (p<0.05) highest (580.00 and 5173.0) in sampling stations C and D respectively. While Water Total Faecal Streptococci (WTFS) and Fish Total Faecal Streptococci (FTFS) followed almost the same trend with the highest values in station D (9.00CFU/100ml and 25.00 CFU/100ml) respectively. The almost sedentary nature of the main reservoir may accounts for its high bacteria load in fish and water. Influx of pollutants through the sampling station C, that is, tributary close to the middle of the reservoir should be checkmated for better water quality. Key words: Effluents, bacteria load, Fish, Water analysis, reservoir --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 13-05-2020 Date of Acceptance: 25-05-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Water is the most widely distributed substance in the natural environment which constitutes the earth’s oceans, seas, lakes, rivers and underground water sources (Du Pleiess, (2017). It is crucial for various aspects of human health, development and well-being; hence the need for its effective and efficient management. Aquatic ecosystems have been suffering changes, in most cases irreversible, often associated with human activities such as deforestation, release of industrial and domestic effluents, and even the use of pesticides in agricultural fields, (Rafael et al,2012). The effects of these changes on fish and water resources often adversely affect the health and economic benefits of the end users.Wakawa et al (2008). Indiscriminate dumping of effluents into water ways is an important factor to be considered and tackled in a bid to ensure a healthy aquatic ecosystem. In Nigeria, the continuous indiscriminate disposal of municipal solid wastes on roadsides, open pits, flowing gully water and drainage channels as a result of increase in human population and urbanization has resulted in contaminated and polluted waters (Adewuyi et al, (2009). Water quality is an index of water pollution and fish is considered as one of the most significant indicators of effluent quality in aquatic environment (Babayemi and Dauda, 2009). The major sources of aquatic contamination are derived from industrial processing plants, leachates from solid waste dumpsites, mechanized farms, industrialization, and increased vehicular use. The quantity and composition of waste generated vary from urban areas to rural areas and likewise from State to State. Ayeni et al (2017). Every household in Ekiti State, more importantly, Ado-Ekiti, the state capital generates waste of different types on daily basis which has negative impact on the environment. Waste management in the Ado