Soil concentrations and soil-air exchange of polycyclic aromatic hydrocarbons in five Asian countries

• Published in: The Science of the total environment Vol. 711; p. 135223
• Main Authors: Hong, Wen-Jun, Li, Yi-Fan, Li, Wen-Long, Jia, Hongliang, Minh, Nguyen Hung, Sinha, Ravindra Kumar, Moon, Hyo-Bang, Nakata, Haruhiko, Chi, Kai Hsien, Kannan, Kurunthachalam, Sverko, Ed
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2020
• Subjects: Fractionation; Polycyclic aromatic hydrocarbons; Soil; Soil-air exchange; Soil; Fractionation; Polycyclic aromatic hydrocarbons; Soil-air exchange
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.135223

[Display omitted] •A total of 47 PAHs were analyzed in soil samples collected in 169 sites from five Asia countries.•Significant positive correlations were found between PAH concentrations and soil organic content.•BaPeq concentrations frequent exceeded the guide lines level.•PAHs concentrations in Chinese soil strong influence by proximity to source region.•Soil has become a secondary source of some 3- & 4-ring PAHs to the atmosphere. The Asia Soil and Air Monitoring Program (Asia-SAMP) is a large-scale monitoring program spanning China, Japan, South Korea, Vietnam and India. 47 polycyclic aromatic hydrocarbons (PAHs) were analyzed in 169 concurrently collected surface soil samples across the five study regions. Total PAH concentrations (∑47PAHs) ranged from 13.1 to 7310 ng/g dry weight, with a median value of 272 ng/g dry weight. Higher concentrations of ΣPAHs were recorded in soils from urban areas, followed by soils from rural areas and background soils. Low correlation coefficients were found between PAHs concentrations with population density, surface air temperature and soil organic content. A trend of depleting high molecular weight PAHs and enrichment of low molecular weight PAHs occurred from east to west in Chinese soils. Based on atmospheric PAHs detected in almost the same sampling sites, the equilibrium status of PAHs in the atmosphere and on the ground was investigated. Sample sites with a soil-air equilibrium status for different PAH congeners recorded differences, and differences were recorded between seasons. 2-ring PAHs were mainly volatilized, and 5- & 6-ring PAHs were mainly deposited in all seasons and across all study regions. 3- & 4-ring PAHs were more affected by soil-air transfer, showing a tendency to accumulate in soils in cold regions/seasons and to be re-volatilized into the atmosphere in warm regions/seasons. Partitioning and exchange of PAHs among soil and air were significantly affected by the air temperature.