This study presents a post-remediation assessment of soil quality at the Olero-Abiteye oil spill corridor in the Niger Delta,following intervention via evacu-ation and Enhanced Natural Attenuation(ENA)techniques.The i...This study presents a post-remediation assessment of soil quality at the Olero-Abiteye oil spill corridor in the Niger Delta,following intervention via evacu-ation and Enhanced Natural Attenuation(ENA)techniques.The investigation evaluates the persistence and interactions of Total Petroleum Hydrocarbons(TPH)and heavy metals across two soil depths(0-15 cm and 15-30 cm)and two seasons(wet and dry),in comparison with control samples.Results indi-cate that TPH concentrations remain significantly elevated across all sampled horizons,with dry season surface soils recording 3945.14±1342.22 mg/kg—well below the EGASPIN intervention threshold of 5000 mg/kg.Heavy metals,notably copper(Cu),also exceeded permissible limits in all depths and sea-sons,with Risk Quotients(RQ)consistently greater than 1.0.Multivariate analyses reveal strong correlations(r>0.75,p<0.01)between TPH,Cu,Pb,and Total Organic Content(TOC),suggesting synergistic sorption mecha-nisms that hinder contaminant mobility but also prolong environmental per-sistence.Principal Component Analysis(PCA)and Hierarchical Cluster Anal-ysis(HCA)further highlight the seasonal and depth-based stratification of pollutants,driven by hydrological and physicochemical dynamics.These find-ings demonstrate that current remediation methods,while partially effective,fall short of fully restoring ecological integrity,particularly within organic-rich surface soils.The study underscores the need for integrated,depth-targeted,and seasonally adaptive remediation strategies to address the coupled behav-iour of hydrocarbons and heavy metals in tropical oil-impacted landscapes.Post-remediation monitoring and enhanced contaminant-specific interven-tions are recommended to ensure sustainable recovery and land reuse.展开更多
文摘This study presents a post-remediation assessment of soil quality at the Olero-Abiteye oil spill corridor in the Niger Delta,following intervention via evacu-ation and Enhanced Natural Attenuation(ENA)techniques.The investigation evaluates the persistence and interactions of Total Petroleum Hydrocarbons(TPH)and heavy metals across two soil depths(0-15 cm and 15-30 cm)and two seasons(wet and dry),in comparison with control samples.Results indi-cate that TPH concentrations remain significantly elevated across all sampled horizons,with dry season surface soils recording 3945.14±1342.22 mg/kg—well below the EGASPIN intervention threshold of 5000 mg/kg.Heavy metals,notably copper(Cu),also exceeded permissible limits in all depths and sea-sons,with Risk Quotients(RQ)consistently greater than 1.0.Multivariate analyses reveal strong correlations(r>0.75,p<0.01)between TPH,Cu,Pb,and Total Organic Content(TOC),suggesting synergistic sorption mecha-nisms that hinder contaminant mobility but also prolong environmental per-sistence.Principal Component Analysis(PCA)and Hierarchical Cluster Anal-ysis(HCA)further highlight the seasonal and depth-based stratification of pollutants,driven by hydrological and physicochemical dynamics.These find-ings demonstrate that current remediation methods,while partially effective,fall short of fully restoring ecological integrity,particularly within organic-rich surface soils.The study underscores the need for integrated,depth-targeted,and seasonally adaptive remediation strategies to address the coupled behav-iour of hydrocarbons and heavy metals in tropical oil-impacted landscapes.Post-remediation monitoring and enhanced contaminant-specific interven-tions are recommended to ensure sustainable recovery and land reuse.
