Ecological risk assessment of Cd, Cr, Ni and Pb metals in Sambreiro river estuary sediment in the Niger Delta Region of Nigeria

ABSTRACT

The characteristic ecological risk of Cd, Cr, Ni and Pb metals in sediment sampled from an estuary (Sambreiro River) in the Niger Delta Region of Nigeria was assessed with the application of some pollution indices and multivariate analysis under quality-controlled conditions. Concentration of Cd and Cr in the stations was in the trend: Cd – St2 > St4 >St1 > St5 > St9 > St8 > St6 > St3 > St10, Cr – St2 > St7 > St5 > St9 > St4 > St8 > St3 > St10 > St1. The relationship between Effects range low- Effects range median (ERL-ERM) and environmental concentration of the metals [M] showed adverse effect occurring occasionally on the sediment biological (i.e. ERL ≤ [M] ˂ ERM) is in the order: St2 > St4 > St1 > St5 > St9 > St8 > St6 > St7 for Cd, only St2 for Cr, and St3 for Pb; while other stations revealed minimal effect (i.e. [M] ˂ ERL) for Cd, Cr, Ni and Pb. The values of mean Effects range median Quotient (m-ERM-Q) indicate that St1, St2, St4, St5, St6 and St9 had 21% probability of toxicity; while St3, St7, St8 and St10 had 9% probability of being toxic. The percentage potential ecological risk factor (%) for the metals across the stations correspond to Cd (70.55) > Pb (22.74) > Ni (4.27) > Cr (2.43); indicating the contribution of Cd as highest to the degree of an ecological risk index for the studied river. Multivariate analysis determined that the possible source of metals in this study location was from the boats manufacturing and fabrication activities taking place in the some of the stations.

KEYWORDS:

• Ecological risk
• metals
• sediment
• multivariate
• Nigeria
• estuary

Acknowledgments

The contributions of the field and laboratory personnel of Niger Delta Aqua Research Group, Prof. M. Horsfall Jnr (Dean, School of Science Laboratory Technology, University of Port Harcourt), Prof. P. C. Mmom (Dean, Faculty of Social Science, University of Port Harcourt) Prof. Amalo-Ndu Dibofori-Orji (Dept. of Chemistry, Ignatius Ajuru University of Education, Port Harcourt, Nigeria), A. R. Shahabinia (Groupe de Recherche Interuniversitaire en Limnologie, Département des Sciences Biologiques, Université du Québecà Montréal) and Dr. M. O. Onyema (Dept. of Pure and Industrial Chemistry, University of Port Harcourt). The authors are grateful to HRH Eze Amb. Sir Dr. Emeka G. Ihunwo (JP. FCAI, Paramount Ruler) and indigenes of Woji community for providing the enabling environment for the research.

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This research received no funding.