Environmental Fate of Hydrocarbons and Contaminants of Emerging Concern in Nigeria: A Critical Review

Nigeria, Africa’s largest oil producer, is experiencing a dual environmental crisis: the persistent contamination of terrestrial and aquatic ecosystems by petroleum hydrocarbons arising from decades of crude oil exploitation, and the increasingly documented occurrence of contaminants of emerging concern (CECs) including pharmaceuticals, microplastics, polycyclic aromatic hydrocarbons (PAHs), and personal care products driven by rapid urbanization and inadequate waste management infrastructure. Despite the acute environmental significance of this issue, a comprehensive, integrated review synthesizing hydrocarbon environmental fate with emerging contaminant dynamics within the Nigerian context remains absent from the literature. This critical review addresses this gap by systematically examining the sources, transport mechanisms, environmental partitioning, degradation pathways, ecological risks, and toxicological implications of both hydrocarbon contaminants and CECs across Nigeria’s major environmental compartments: soil, surface water, groundwater, sediment, and biota. Special attention is devoted to the Niger Delta the epicenter of hydrocarbon pollution where PAH concentrations in crude oil-impacted soils have been recorded at averages of 29,953 ng/g for Σ29PAHs, far exceeding international remediation thresholds. The review further highlights knowledge gaps including the near-total absence of integrated co-exposure studies, insufficient long-term monitoring data, the underrepresentation of northern Nigerian environments, and a lack of robust regulatory frameworks. Priority research directions and policy recommendations are proposed to bridge these gaps and support Nigeria’s environmental remediation agenda.