Physico-Chemical Assessment of Ogba River, Benin City, Southern Nigeria for Water Quality Index and Pollution Control

Abstract

The purpose of this study was to evaluate the level of pollution in the Ogba river's surface water by utilizing physical, chemical, principal   component analysis (PCA) and water quality index methods. Water samples for physicochemical characteristics were taken from four sites, and the resulting data were analyzed using the appropriate statistical software. With the exception of flow rate, air and water
temperatures, pH, DO, Cl-, P, NH4-N, NO2, and SO₄^2-, all other parameters varied significantly (P<0.05) between the study stations. however, all the parameters within Federal ministry of Environment (FMEnv) and World Health Organization (WHO) standards for surface water, with the exception of the DO, which was below allowable limits while BOD and COD were above FMEnv allowable levels. Water
Quality Index (WQI) revealed that stations 3 and 4 had poor water quality with values of 3.07 ±0.48 and 3.02±0.41 for BOD in station 3 and 4 and 19.70 ±7.33 and 27.55 ±13.20 for COD in both stations. The first five PCA explained 83.913% (the benchmark for water quality index(WQI) for suitable water is between 50-100), revealing that the main environmental factors influencing the water quality were color,
electrical conductivity, turbidity, sodium, phosphate, total dissolved solids and total suspended solids which were attributed to anthropogenic activities around the river. The presence of organic wastes as shown by low DO and increased BOD concentrations indicate that the river's water quality is deteriorating with potential health risks.