Fate and behaviour of nitrogen-containing polycyclic aromatic hydrocarbons in soil

• N-PAHs are present in hydrocarbon polluted soils, often in the presence of PAHs.
• There is a lack of information on the presence and behaviour of N-PAHs in soil.
• N-PAHs are typically more toxic and more mobile than homocyclic PAHs.
• N-PAHs are typically less biodegradable and more persistent than homocyclic PAHs.

Nitrogen-containing polycyclic aromatic hydrocarbons (N-PAHs) are analogues of the homologous polycyclic aromatic hydrocarbons (PAHs) in which one or more carbon atom(s) is replaced with nitrogen atom(s). They do not only exist in conjunction with the homocyclic PAHs in polluted systems, but unlike PAHs, they are intentionally produced. It has also been reported that heterocyclic PAHs contribute to the toxic effects identified in many environmental samples, containing PAH/N-PAH mixtures. N-PAHs are toxic, often displaying greater biological effects than their homocyclic analogues. As these chemicals are suspected of being carcinogens in humans and other biota, there is a need to know their fate, behaviour, bioavailability, ecotoxicity, and biodegradation for risk assessments of contaminated soils. The aim of this review is to consider the presence and behaviour of N-PAHs, focusing on their bioavailability, ecotoxicity and biodegradation in the soil environment.