Pedosphere 24(5): 575--584, 2014
ISSN 1002-0160/CN 32-1315/P
©2014 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| PAHs sorption and desorption on soil influenced by pine needle litter-derived dissolved organic matter |
YANG Xiu-Hong1,2, P. GARNIER3, WANG Shi-Zhong1,2, V. BERGHEAUD3, HUANG Xiong-Fei1,2 and QIU Rong-Liang1,2 |
1School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)
2Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275 (China)
3INRA, UMR1091 EGC, BP 01, F-78850 Thiverval-Grignon (France) |
| ABSTRACT |
| Study of the relationship between plant litter-derived dissolved organic matter (DOM) and organic pollutant transport in soil is important for understanding the role of forest litter carbon cycling in influencing pollutant behaviour and fate in forest soil. With the aim of providing insight into the capacity of plant litter-derived DOM to influence sorption and desorption of selected polycyclic aromatic hydrocarbons (PAHs) on soil, batch experiments were carried out with application of a sorption-desorption model incorporating DOM effects. Freshly fallen pine (Pinus elliottii) needles were used as the source of organic matter. Input of the pine needle litter-derived DOM was found to significantly decrease desorption hysteresis as well as soil adsorption capacity of phenanthrene (PHE) and fluoranthene (FLA). Addition of 1 728 mg L-1 dissolved organic carbon (DOC) lowered the organic carbon-normalized sorption distribution coefficient of PHE from 7 776 to 2 541 L kg-1 C and of FLA from 11 503 to 4 368 L kg-1 C. Decreases of the apparent sorption-desorption distribution coefficients of PHE and FLA with increased DOC concentration indicated that DOM favored desorption of PAHs from soil. Increases in the fraction of apparently dissolved PAHs were attributable to the dissolved PAH-DOM complexes, accounting for the dissolved proportions of 39% to 69% for PHE and 26% to 72% for FLA in the sorption and desorption processes as the concentration of the added DOM solution rose from 0 to 1 728 mg L-1. Our results suggest that pine needle litter-derived DOM can have a substantial effect of inhibiting PAHs sorption and promoting PAHs desorption, thus leading to enhanced leaching in soil, which should be taken into account in risk assessment of PAHs accumulated in forest soil. |
| Key Words: dissolved organic carbon, distribution coefficient, fluoranthene, hysteresis, phenanthrene |
| Citation: Yang, X. H., Garnier, P., Wang, S. Z., Bergheaud, V., Huang, X. F. and Qiu, R. L. 2014. PAHs sorption and desorption on soil influenced by pine needle litter-derived dissolved organic matter. Pedosphere. 24(5): 575-584. |
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