Factors affecting spatial variation of polycyclic aromatic hydrocarbons in surface soils in North China Plain

Abstract

The spatial variation in concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in surface soils in the North China Plain and the influential factors were examined in the present study. High concentrations of the sum of 16 PAHs (∑PAH(16) ) appeared in cities and their surrounding areas. Emissions and soil organic carbon (SOC) content significantly regulated spatial differentiation of PAH contamination in soils in the study area. Compared with emissions, concentrations of individual and total PAHs in soils were more closely controlled by the SOC content. Furthermore, concentrations of PAH species with lower molecular weight (e.g., two- or three-ring) in surface soils were more strongly correlated with the SOC content in comparison with those of higher molecular weight (e.g., five- or six-ring), mainly because of their higher saturated vapor pressure, thus higher mobility. The spatial variation of PAH species in soils in the North China Plain tended to be larger with increasing benzene ring numbers, and the difference in physicochemical properties of PAH species determined their distinct spatial distribution characteristics. The present study highlights the relative importance of emissions and SOC content in spatial variation of PAHs and the dependence of the spatial distribution characteristics of PAH species in surface soils on their physicochemical properties at a regional scale. Results of the present work are helpful for regional risk assessment of the contaminants tested.

Polycyclic aromatic hydrocarbons in Chinese surface soil: occurrence and distribution

“…A significantly positive correlation (p<0.05) between emission inventory and measured PAH concentration in soil was also observed in the North China Plain (Wang et al 2012). These studies revealed that concentrations and distributions of PAHs in surface soils were highly dependent on their emissions (Wang et al 2012).…”

“…The result indicated that PAH emission was the important factor influencing PAH concentration in Chinese surface soil, which is called the primary distribution pattern (Li et al 2010b). A significantly positive correlation (p<0.05) between emission inventory and measured PAH concentration in soil was also observed in the North China Plain (Wang et al 2012). These studies revealed that concentrations and distributions of PAHs in surface soils were highly dependent on their emissions (Wang et al 2012).…”

Spatio–Temporal Distribution of Polycyclic Aromatic Hydrocarbons in Urban Soils in Cape Town, South Africa

“…A weak correlation between the SOM and PAH concentrations in summer suggests that soil samples were perhaps contaminated to different levels, probably due to easy degradation of the PAHs. Another possible reason can be due to the fact that the PAH emission point source could be low even if the SOM is high (Wang et al 2012). However, the moderate correlation in winter can be explained by the fact that during the winter season, PAH degradation is expected to slow down.…”

Assessing the Spatial Distribution of Soil PAHs and their Relationship with Anthropogenic Activities at a National Scale

“…The results were similar to those issued by Cao et al [40] and Zhang and Chen [44], who determined that PAH concentrations in surface soils in this country occurred in descending order from northern to southern China by collecting data from 1999 to 2008 and from 2006 to 2016, respectively. Due to the low temperatures in the northern areas, the evaporation and diffusion of PAHs is limited [100]. This might be one of the reasons for the presence of high levels of PAHs in surface soils in the northern areas of China.…”