Physicochemical properties and metal speciation in gas flare-impacted soils in Ibeno, NigeriaPhysicochemical properties and metal speciation in gas flare-impacted soils in Ibeno, NigeriaPhysicochemical properties and metal speciation in gas flare-impacted

Abstract

The physicochemical properties and metal speciation in gas flare-impacted soils in Ibeno, Nigeria was assessed in this study. During the study, surface soils were collected from five (5) communities impacted by gas flaring within Ibeno namely: Ukpenekang, Mkpanak, Atabrikang, Inua-Eyet Ikot, and Okorutip. Surface soils were also collected from a location outside Ibeno where there is no impact of gas flaring and used as the Control. These samples and Control were treated analytically and analysed for their physicochemical properties and the different fractions of the metals using standard procedures. Results obtained in the studied soils indicated that, the mean values of pH, organic carbon, electrical conductivity, and cation exchange capacity were all within their acceptable limits. The mean total concentrations of lead (Pb), cadmium (Cd), and nickel (Ni) were also within their recommended limits whereas, the mean total concentration of iron (Fe) was higher than the acceptable limit. However, the levels of all the physicochemical properties including the total concentrations of the trace metals in the studied gas flare-impacted soils were much higher than their levels in the control plot. Results of metal speciation in the studied soils revealed that, Pb and Cd existed predominantly in the acid extractable fraction, Ni in the reducible fraction while, Fe existed mainly in the residual fraction. Nevertheless, in the control plot Pb and Cd existed predominantly in the reducible fraction, Ni in the residual fraction while Fe existed in the residual fraction. The Principal component analysis revealed that anthropogenic factor impacted significantly on all the parameters determined except Fe. The Hierarchical cluster analysis confirmed that, all the parameters determined except Fe emanated mainly from the anthropogenic source and also indicated strong relationships among the parameters. The study revealed that, all the metals in the studied gas flare-impacted soils were in the moderate class of contamination factor. The ecological risk factor and potential ecological index of the metals were in the low ecological risk.