The potential of sewage sludge-derived biochar and humus mixtures for attenuation of polycyclic aromatic hydrocarbons (PAHs) in crude oil contaminated soil was evaluated. Laboratory-scale experiments involving ultisol samples spiked with crude oil, sewage sludge-derived biochar, and mixed biochar with humus sediment were monitored for removal of PAHs at the intervals of 1, 6, and 12 months. The results revealed that out of the three biochar products obtained at different pyrolysis temperatures: 500, 700, and 900 °C (designated BC500, BC700, and BC900, respectively), BC700 recorded desirable properties and acceptable levels of PAHs suitable for soil amendment. Characterisation of the mixture for functional groups using Fourier transform infrared spectroscopy (FTIR) and surface morphology using scanning electron microscopy (SEM) revealed the presence of oxygenated and nitrogenated species that could support mineralisation of PAHs, increased surface area as well as pores to aid pollutant adsorption. The study revealed that the derived mixture demonstrated the potential to reduce the level of PAHs in contaminated soil. About 70% maximum reduction in the levels of total PAHs was recorded within 1 month for soil treated with the derived mixture in comparison to the control experiment.

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Polycyclic aromatic hydrocarbons (PAHs) are among the world's most significant environmental organic contaminants because of their carcinogenic properties.PAHs are widely distributed globally as a result of releases from numerous natural and anthropogenic activities. Consequently, several PAH monitoring studies have been conducted and remediation approaches explored. This article aims to provide the current status of PAH distribution in Nigeria's oil and gas industrial region in relation to the technologies adopted for PAH remediation.Ideally, the findings will provide insight into the challenges in managing organic contaminants derived from petroleum exploration activities in developing countries with Nigeria as a case study.

This study measured and compared the levels of trace elements (Pb, Hg, Cr, Ni, V, Cu, Cd, Mn, Fe, Zn, Co, and As) at Aba and Port Harcourt respectively. Paired independent t-test at p ≤ 0.05 (df = 34, n = 36) confirmed significant seasonal variations in the concentrations of the metals with greater concentrations during the dry season. Enrichment factor (EF) analysis was adopted to identify the sources and their contributions to particulate matter. Our results revealed that the background atmosphere in the studied cities was highly affected by anthropogenic pollution, in the order PH > Aba > Eket > Calabar, and demonstrated that high heavy metal concentrations occurred but with significant EF values during the dry season. The present study provides base line information about the region. The results are useful for effective environmental pollution monitoring in the in the Niger Delta air basin.