Assessment of Njaba River Quality Using Physico-Chemical Parameters

Abstract

The study analyzed the physico-chemical parameters of Njaba River in Imo State, Nigeria. Triplicate water samples were collected in May, 2023 at five sampling points for physico-chemical analysis using standard methods. Mean concentrations of turbidity (15.60±2.86 NTU), TSS (83.48±7.26 mg/L), Pb (0.078±0.030 mg/L), Zn (0.225±0.054 mg/L) and Ni (0.254±0.012 mg/L) exceeded the Federal Ministry of Environment’s maximum permissible limits. Narrow variation was recorded for temperature while wide variations were recorded for turbidity, TS, TSS and Pb. These were a clear indication of human activities such as sand excavation runoff, agricultural runoff as well as effluent discharge from a brewery into the river. The One-Way ANOVA test revealed that mean concentrations of DO, BOD, COD, turbidity, TS, TDS, TSS, NO3-, PO43, Pb, Zn and Ni ions (Sig.values=0.000 each), as well as those of water temperature (Sig.value=0.003) all differed significantly across the sampling locations at p<0.05. Post-hoc Duncan Multiple Range test revealed that the difference in concentrations of BOD, TS, TSS, Zn and Ni occurred mainly between the impacted and control locations. It was observed that the water was slightly polluted giving the high levels of turbidity and total suspended solids, as well as those of heavy metals (Zn and Ni) resulting from discharge of brewery effluent, sand excavation, solid waste dumping and agricultural practices in and around the water body.