Investigation of geospatial distribution of PAH compounds in soil phase and determination of soil–air exchange direction in a megacity

Sixteen priority polycyclic aromatic hydrocarbons in roadside soils at traffic light intersections (Bratislava, Slovakia): concentrations, sources and influencing factors

“…Soil, depending on temperature, acts as a secondary source of PAHs to the atmosphere, especially LMW PAHs, while for HMW PAHs, soil is considered to be their sink (Bozlaker et al, 2008). Taking into account also the faster microbial degradation and higher mobility of LMW PAHs in soils, these loss mechanisms can lead to temporal variability of LMW-PAH concentrations in soils (Wang et al, 2012) and non-equilibrium conditions as shown by studies on PAH exchange in the soil-air system (Cousins et al, 1999;Wang et al, 2014;Cetin et al, 2017;Orazi et al, 2020;Yukhimets et al, 2020). The dynamic transfer of Ace, Acy, Nap and Flu in the soil-air system could be the reason for the non-attainment of sorption equilibrium of these volatile PAHs with soil organic matter, which may be reflected in weak or no correlations with TOC.…”