The demand for processed petroleum products and agricultural produce has exposed our environment to polycyclic aromatic hydrocarbons (PAHs) contamination. PAHs stick to solid sediments and are ubiquitous including soil, water and air. Their presence in these media creates problems because consuming products obtained from these sources could be deleterious to human health since several of these compounds (benz(a)anthracene, benzo(a)pyrene, chrysene etc) have been implicated in causing tumors in animals and cancer in humans. The present review describes several remediation techniques which are efficient and cost effective in removing PAHs from the environment. Some of these conventional clean-up methods are not only environmental friendly; they also present a novel approach in reducing the ability of PAHs to cause prospective risk to humans and the ecosystem.

This study examines the adsorption thermodynamics and kinetics of heavy metal ions [(Hg (II), Cd (II), Pb (II)] on a demineralized lignite coal. The study also investigates the effects of process parameters like contact time, pH, concentration of metal ion, temperature and adsorbent mass on the extent of metal-ion adsorption from solution.The results of the kinetic studies show that the adsorption reaction is first order with respect to the metal cation solution concentration, with activation energies of 4.9, 8.2 and 9.1 kJ mol ±1 for Hg (II), Cd (II) and Pb (II), respectively. These low activation energy values indicate that the adsorption reaction is diffusion-controlled. The results of the thermodynamic investigations indicate that the adsorption reactions are spontaneous (DG < 0), slightly exothermic (DH < 0) and irreversible (DS > 0).The results of the study further show that the adsorption process is pH, adsorbent mass and metal-ion concentration dependent. Adsorption increases with increase in these variables. Temperature has only a marginal effect on adsorption. The reasons for these observations have been suggested.

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Environmental impact assessment (EIA) came into being in Nigeria with promulgation of the Act establishing three independent EIA systems-the EIA Decree 86 (1992), the Town and Country Planning Decree 88 (1992) and the Petroleum Act (1969). Despite a sound legal basis and comprehensive guidelines, evidence suggests that EIA has not yet evolved satisfactorily in Nigeria, as the current system amounts to duplication of efforts and cost. An evaluation of the EIA system against systematic evaluation criteria, based on interviews with EIA approval authorities, consulting firms and experts, reveals various shortcomings of the EIA system. These mainly include inadequate capacity of EIA approval authorities, deficiencies in screening and scoping, poor EIA quality, inadequate public participation and weak monitoring. Overall, most EIA study rarely meets the objective of being a project planning tool to contribute to achieving sustainable development and mitigate impact from development project. The work concludes on the suggestions to involve in EIA process relevant authorities and to increase the competence of EIA consultants.

An experiment was conducted to assess the influence of arbuscular mycorrhizal (AM) fungi on the performance of Phaseolus vulgaris under crude oil contaminated soil. P. vulgaris was grown on soil under 2%, 4% and 8% (v/w) crude oil contamination. The experimental units were biostimulated with 2 g NPK fertilizer pot −1 and were inoculated with 12 g AM inoculum pot −1. Non inoculated pots served as control. The results showed that AM inoculated pots recorded higher and significantly (P < 0.05) different dry matter yields and chlorophyll content than non AM inoculated pots. Residual total petroleum hydrocarbon (TPH) increased as percent crude oil contamination increased. Total petroleum hydrocarbon decomposition and removal was higher on pots inoculated with AM than non inoculated pots. With AM colonization, physiological characteristics of P. vulgaris and TPH decomposition improved. This is evinced by the linear regression analysis between colonization and TPH (R 2 = 0.77).