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The Impact of Different Root Exudate Components on Phenanthrene Availability in Soil
Author(s) -
Sun Bingqing,
Gao Yanzheng,
Liu Juan,
Sun Yandi
Publication year - 2012
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2011.0417
Subject(s) - phenanthrene , chemistry , malic acid , sorption , desorption , environmental chemistry , organic matter , soil organic matter , soil water , organic chemistry , citric acid , soil science , adsorption , environmental science
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. Four typical RECs were compared including malic acid, alanine, serine, and fructose. An n ‐butanol extraction procedure and a sorption–desorption experiment were used to predict the availability of phenanthrene in soil. We found that the n ‐butanol extractable amounts of phenanthrene in soil increased with increasing REC concentrations. The extractability of phenanthrene in soil with various treatments decreased in the following order: malic acid > alanine > serine > fructose treatments. Organic acid (malic acid) resulted in the most significant increase in PAH extractability by soil. Phenanthrene sorption by soil could be described using a linear model regardless of the presence of RECs. The simulated distribution constants ( K d ) and carbon‐normalized distribution constants ( K oc ) for phenanthrene sorption decreased significantly with the addition of all test RECs. Malic acid enhanced desorption of phenanthrene from soils. In contrast, lower concentrations of test amino acids promoted phenanthrene desorption, while higher concentrations inhibited desorption. Fructose had a minimal effect on PAH desorption. 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.