Evaluation of concentrations and contamination factors of potentially toxic elements in sediments of Egi communities, Rivers State, Nigeria

Potential toxic elements in sediments and water are harmful to humans and other organisms even at low concentration. Therefore, the objective of this paper was employed to evaluate the concentrations and contamination factors of potential toxic elements (PTE) in sediments of selected areas in Egi communities (Obagi, Oboburu and Ogbogu) in Ogba/Egbema/Ndoni LGA of Rivers State, Nigeria using AAS (GBC XplorAA) after mixed-acid wet digestion of the sediment. The result of the levels of PTEs reveals that the highest mean were iron (6983±123 mg/Kg), manganese (19.42±6.87 mg/Kg), zinc (11.73±2.10 mg/Kg) copper (7.057±1.08 mg/Kg), and lead (5.871±2.76 mg/Kg). The result also showed that the most toxic metals had values as follows: cadmium: Obagi (1.244±0.01 mg/Kg), Oboburu (0.411±0.01 mg/Kg) and (0.051±0.01 mg/Kg); arsenic; Ogbogu (2.481±0.31 mg/Kg), Obagi (1.452±0.02 mg/Kg), and Oboburu (0.991±0.02 mg/Kg), copper Oboburu (5.333±0.010 mg/Kg), Obagi (6.800±0.07 mg/Kg), and Ogbogu (9.037±0.12 mg/Kg). The geo-accumulation (Igeo) values indicated uncontaminated for all the PTEs. The contamination factor shows that all samples had low contamination. The enrichment factor for Obagi; Pb (1.011), As (0.675), Cr (0.467), Cu (1.052), Zn (0.650), Ni (0.493), and Co (0.767) were of biogenic, while Cd (45.42) was of anthropogenic origin. For Oboburu; biogenic origin were As (0.321), Cr (0.188), Mn (0.003), Cu (0.574), Zn (0.709), Ni (0.313), and Co (0.454) while Pb (2.100), Cd (5.756) were of anthropogenic origin. Ogbogu; Cr (0.845) and Mn (0.807) were of biogenic while Pb (5.079), Cd (4.241), As (4.770), Cu (5.780), Zn (2.339), Ni (2.135) and Co (5.586) were of anthropogenic sources. The order of toxicity was Fe>Mn>Zn>Cu>Cr>Pb>Ni>Co>Cd>As>Hg. The order of impact were Ogbogu>Obagi>Oboburu.