The Impact of Different Root Exudate Components on Phenanthrene Availability in Soil

摘要

This study investigated the impact of different root exudate components (RECs) on the availability of phenanthrene as a representative of polycyclic aromatic hydrocarbons (PAHs) in soil (TypicPaleudalfs) using laboratory batch assays.Six typical RECs were compared including citric acid,oxalic acid,malic acid,alanine,serine,and fructose.An n-butanol extraction procedure and a sorption experiment were used to predict the availability of phenanthrene in soil.We found that both the n-butanol extraction and sorption process increased the availability of phenanthrene with increasing REC concentrations.The availability of phenanthrene in soil with various treatments decreased in the following order:organic acids (citric acid＞oxalic acid＞malic acid) ＞amino acids (alanine ＞serine)＞fructose treatments.The mechanism of REC-influenced availability of PAH in soil is discussed based on the observed metal dissolution,soil organic matter reduction,and dissolved organic matter release from soil solids.