Study on the physicochemical properties and heavy metal status of sediment samples from Ohii Miri river in Abia State, Nigeria

Abstract

The physicochemical properties and heavy metal status of sediment samples from Ohii Miri River in Abia State, Nigeria were studied. The section of the river studied (from Ahia-Eke to Amaoba-Ime) was divided into three segments designated as Stations A, B, and C. Five sediment samples were collected at each location. Values obtained from the five sampling points were averaged. The sediment samples were analyzed for pH, electrical conductivity, % organic carbon, % organic matter, % ammonium nitrogen, % nitrate nitrogen, % nitrogen, % sand, % silt, % clay, and heavy metals (Fe, Pb, Zn, Mn, Ni, Cd, and Cr) in the rainy and dry seasons respectively using standard procedures. Correlation analysis was also employed to examine the relationship between the various parameters in the sediment samples. The results obtained for heavy metals were compared with USEPA standard. The results showed that the sediment was acidic and the heavy metals concentrations exceeded the USEPA standard. Positive correlations were found to exist between Pb with Zn, Ni; Fe with Ni as well as Ni with Cd in the rainy season. In the dry season, Ni correlated positively with Pb, Zn; Cd with Pb, Ni. Positive correlations existed between Cr in dry season with Cr in rainy season and Pb in dry season with Cr in rainy season. PER indices (contamination factor, degree of contamination, ecological risk factor, sum of the individual potential risk, and geo-accumulation factor) have been calculated. Values of geo-accumulation factor showed that the sediment is not polluted with the studied heavy metals. Keywords: Ohii Miri River; Physicochemical parameters; heavy metals; Concentration; Permissible limit; Correlation; Potential ecological risk.