Water quality assessment of Osun River: studies on inorganic nutrients.

The present investigation provides data of some ions, namely Na+, Ca2+, NH4+, Cl-, NO3-, CN- and PO4(3-) on water samples of river Osun, selected rivers in the region and groundwaters. The pH, temperature, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH) and total carbon (IV) oxide (TCO2) have also been determined to asses the chemical status and pollution levels of these water sources. The higher values of certain parameters with respect to the acceptable standard limits for drinking water indicate the pollution in both groundwater and river water samples of the study area, and make the waters unsuitable for various applications. The high pollution river water source showed higher levels of phosphate, nitrate and ammonium ions (P < 0.05). There is no significant difference (P < 0.05) between the mean concentrations of other inorganic nutrients in the high and low pollution water source types. The correlation coefficient between quality parameter pairs of river water and groundwater samples are determined and the significance of these parameters in both types of water sources are discussed.