Hierarchy of factors which influence polycyclic aromatic hydrocarbons (PAHs) distribution in river sediments

The sediment environment provides habitat for fauna and flora. As pollutants can interchange between water and sediments, pollution will exert a significant influence on the water environment. Previous studies on polycyclic aromatic hydrocarbon (PAHs) pollution of sediments have primarily focused on the comparison of concentrations between seasons, land uses and species. Studies on the identification of the hierarchy of factors which influence PAHs distribution and its variability in river sediments are limited. This paper discusses a comprehensive investigation into the inherent variability of PAHs in sediments and the primary factors which influence this variability. The study outcomes confirmed that key factors exerting influence on PAH distribution in sediments can be ranked in the order: land use > population > seasons. Accordingly, intensive urban land use was identified as the most important factor influencing PAHs distribution. Additionally, it was found that with increasing urban development, PAHs concentrations and their variability in sediments increase in terms of the molecular weight of different species. The study outcomes are expected to enhance management strategies to mitigate PAHs pollution of urban water environments including the prioritisation of factors requiring management and the selection of appropriate approaches in the context of cost-effectiveness.