Assessment of surface water quality of Onuiyieke river in Imo State, Nigeria

This research aimed to assess the surface water of Onuiyieke River to ascertain its quality status. Measurements were made on samples collected from seven locations with 500ml sample bottles according to standard methods. Samples for heavy metals were collected in 250ml bottle and fixed with concentrated HN03. Descriptive analysis, variation plots, ANOVA, Duncan Multiple Range tests, Principal Components Analysis (PCA), Pearson Correlation (r) and Water Quality Index (WQI) were used to analyze data. Mean values of the parameters obtained were: Total Suspended Solids (TSS) 198.19 ± 80.93mg/L; Electrical Conductivity (EC) 331.81 ± 59.78µ; Turbidity 18.84 ± 2.22 NTU; Nitrate ions 14.77 ± 0.92mg/L; Dissolved Oxygen (DO) 6.58 ± O.22mg/L and Biological Oxygen Demand (BOD) 1.77 ± 0.10mg/L. Mean values of the Trace Metals obtained were: Iron (Fe) 1.93 ± 0.23mg/L; Magnesium (Mg)0.22 ± 0.02mg/L and Calcium (Ca) 15.15 ± 1.87mg/L while the mean value of Faecal Coliform was 1.91 ± O.10MPN/100. pH, EC, TSS, BOD, turbidity, N03-, Ammonia, Fe and Faecal coliforms exceeded the NESREA and WHO maximum permissible limits. There were significant spatial differences in levels of TDS, EC, NO3, NH3, DO and Faecal coliforms (Sig F=0.000 to 0.039) and significant temporal differences in levels of PO43- (Sig F= 0.078 to 1000) between the control and other locations at p<0.05. Four Principal Components (PCs) formed the extraction solution with a cumulative percentage variability of about 77.67%. The Water Quality Index revealed that the rating for the water quality across the sampling locations was between excellent and unsuitable. Appropriate monitoring procedures for the sustainable development of the river should also be put in place.