Pollution Assessment and Index Properties of Okpulor Soils, Rivers State, Nigeria: Geochemical Characterization, Geotechnical and Geoenvironmental Implications

Abstract Soil, a vital biosphere component, is pivotal for human life, but its degradation adversely affects life quality. This study assessed soil pollution and index properties in Okpulor through geochemical, geotechnical, and geoenvironmental analyses. Twenty samples, comprising 14 surface and 6 shallow subsurface ones, underwent geochemical analysis for heavy metals (Fe, Cr, C, Cu, Zn, Ni, and Pb). Six geochemical models including Geoaccumulation Index (Igeo), Enrichment Factor (EF), Contamination Factor (CF), Metal Pollution Index (MPI), and Potential Ecological Risk Index (PERI) were employed. Simultaneously, six subsurface samples underwent geotechnical analysis for Natural Moisture Content, Grain Size, Specific Gravity, Bulk Density, and Atterberg Limits according to USCS and AASHTO guidelines. The Igeo highlighted significant Cd contamination, urging Cd source reduction for environmental mitigation. EF above 1.5 revealed substantial anthropogenic influence, emphasizing human activity control. CF accentuated Cd's contribution, requiring specific attention in environmental management. The PERI stressed Cd's ecological risks, necessitating targeted interventions. Natural moisture revealed initial soil conditions affecting contaminant mobility. High content enhanced leaching, emphasizing potential water-soluble contaminant migration. Bulk density and specific gravity assessed soil compaction and permeability, vital for understanding contaminant movement. Atterberg limits provided insights into plasticity and moisture retention, influencing contaminant behavior. Grain size analysis characterized particle distribution, impacting porosity, permeability, and contaminant movement. The interplay between geotechnical and geochemical properties unveiled contamination risks, urging holistic environmental management in Okpulor. Comprehensive consideration of the soils geotechnical index properties in environmental studies provides a holistic view of soil-contaminant interactions, emphasizing the need for strategic environmental management in Okpulor.