Effects of dissolved organic matter on phenanthrene adsorption by soil
Xiong, W.; Ling, W-ting.; Gao, Y-zheng.; Li, Q-ling.; Dai, J-yu.
Ying Yong Sheng Tai Xue Bao 18(2): 431-435
2007
ISSN/ISBN: 1001-9332 PMID: 17450752 Document Number: 611257
This paper studied the effects of exotic and native dissolved organic matter (DOM) on the phenanthrene adsorption by three soils differed in soil organic carbon content (f(oc)). The exotic DOM came from decayed rice straw, while the native DOM was extracted from the test soils. In all cases, the adsorption of phenanthrene by treated soils could be well described with linear-type model, and there was a positive correlation between adsorption coefficient ( K-d) and f(oc.) Compared with the control, the K-d value of test soils after native DOM removed was increased by 7.08 % -21. 4 %, and the increment (Delta K-d) was positively correlated with f(oc), indicating that the presence of soil native DOM impeded the phenanthrene adsorption by soil. The effects of exotic DOM on phenanthrene adsorption had a close relation with its added concentration in soil-water system. Within the range of 0-106 mg DOC center dot L-1, the K-d value increased first, and then decreased with the increase of added exotic DOM concentration. Lower concentrations of added exotic DOM promoted the phenanthrene adsorption by soil, while higher concentrations ( >= 52 mg DOC center dot L-1) of it obviously im peded this adsorption. These effects of exotic and native DOM on soil phenanthrene adsorption were considered to be related to the association of phenanthrene with DOM in solution, and the ' cumulative adsorption effect' between soil solid and aqueous phases.