Hydrochemistry and Water Quality Indices of River Ose Water, Southern Nigeria

Abstract

<jats:p>Background Objective: River Ose has flowing water throughout the year that can serve for irrigation and domestic purposes. This study examined the hydrochemistry, water quality indices and coliform counts of River Ose Water, Nigeria with a view to ascertain its suitability for drinking and irrigation.Materials and Method: For this purpose, 15 water samples were collected along the flowing river channel and subjected to physico-chemical and e-coli determination using standard methods. Water quality index (WQI) and Irrigation parameters (Sodium adsorption ratio (SAR), Percentage sodium (%Na), Residual sodium bicarbonate (RSBC), Kelly’s ratio (KR), Permeability index (PI) and Magnesium absorption ratio (MAR)) were calculated from the chemical data obtained from the analyses.Results: Results of the analyses revealed that pH (9.7 pH of the water samples were of alkaline nature with all the water samples exceeding approved standard for drinking water. Drinking alkaline water may deactivate pepsin but it could lead to gastrointestinal problems and metabolic alkalosis. Electrical conductivity (µS/cm), Total dissolved solids (mg/L) as well as Total hardness of all analyzed water samples fell in the category of fresh water. HCO3- and Cl- were the dominant anions while Na+ and K+ constitute the dominant cations in the water chemistry. The abundance of major ions revealed Na+&gt; K+ &gt;Mg2+&gt;Ca2+ and HCO3-&gt;Cl-&gt;SO42-&gt;NO3- trend. The dominant hydrogeochemical facies was mixed Ca2+-Na+-HCO3- (93%) with few mixed Ca2+-Mg2+-Cl- (7%) while calculated WQI was 89.44. All samples tested positive to e-coli count ranging from 1.71*101 – 8.100*103.Conclusion: The analyzed physico-chemical parameters in all River Ose water samples were well within approved desirable limits except for the pH. However, the water was not potable as all samples tested positive to e-coli counts. In addition, WQI calculation revealed that the water has very poor drinking quality. Sources of ions in the River were predominantly from rainfall and minor weathering from the bedrocks. Irrigation quality parameters (SAR, %Na, RSBC and KR) indicated that River Ose water was good for irrigation. However, applying the water on salt sensitive plants is not advisable as irrigation evaluation employing PI and MAR showed that the water was not suitable for irrigation.</jats:p>