Effect of low-molecular-weight organic acids and amino acids on the sorption of phenanthrene in Typic Paleudalfs
几种低分子量有机酸和氨基酸对黄棕壤吸附菲的影响

The sorption of phenanthrene by TypicPaleudalfs with the addition of low-molecular-weight organic acid (LMWOA) and amino acid as representatives of typical root exudates was investigated using a batch experimental method. Phenanthrene sorption isotherms by TypicPaleudalfs could be well described by a linear sorption model irrespective of the addition of organic and amino acids. The addition of organic and amino acids significantly inhibited the sorption of phenanthrene by soil, and the larger amounts of these root exudates added in soil resulted in the stronger inhibition of phenanthrene sorption. Comparing with amino acids, LMWOAs displayed stronger inhibition ability of phenanthrene sorption in soil. The inhibitory ability of test five organic and amino acids for phenanthrene sorption was in the order of oxalic acid > citric acid > malic acid >> alanin > serine. The concentrations of dissolved organic matter (DOM) in equilibrium solution of phenanthrene sorption were detected, and were observed to be higher with the addition of organic and amino acids, while the soil organic carbon (foc) content was observed to be little lower with the root exudate addition. The partition of phenanthrene into DOM in solution was proposed to be the main cause for the decrease of phenanthrene sorption in soil with the addition of test root exudates.