Sorption of PAHs in the Soil Environment with Emphasis on the Role of Soil Organic Matter: A Review

Abstract: Recently sorption of organic pollutants, in particular polycyclic aromatic hydrocarbons (PAHs), has received much attention and researchers agree that organic matter (the amount of organic matter and its nature) is the most important factor affecting the sorption, desorption and fate of organic pollutants in soil and sediments. It is well documented that organic matter of soil and sediments is the main factor to govern the sorption of PAHs and other nonionic compounds in soil and sediments. However, the sorption capacity and affinity of organic matter of different compositions are differs greatly. Therefore; more research is required to understand how the chemical structure of organic matter can control the fate of the pollutants. Many studies have shown that the aliphatic groups of organic matter are responsible for the sorption properties of nonionic organic pollutants such as PAHs On the other hand, several studies have suggested that the key role in the sorption and desorption of PAHs and some nonionic pollutants was played by aromatic domains of organic matter in soil and sediments. Some researchers, do not agree on how the nature of the organic matter affects the sorption properties and sometimes they contradict each other. This article reviews the fate of PAHs in the soil environment. The review emphasizes sorption process especially the role of soil organic matter in sorption behaviors of PAHs.