The Contribution of Rhizosphere to Remediation of Polycyclic Aromatic Hydrocarbons (PAHs) and Their Toxicity in Soil: Evaluating with Sequential Extraction and Toxicity Risk
To investigate the effects of rhizosphere process on PAHs bioavailability, a sequential solvent extraction experiment was implemented to identify extractable and non-extractable PAHs in rhizosphere and bulk soils of horsebean. The results showed that the primary fraction was methylene chloride (DCM)-extracted and crude-humin-bound PAHs among extractable and non-extractable fractions, respectively. The proportions of sum toxicity concentrations of DCM-extracted fraction decreased sharply in rhizosphere. The partial least square regression model indicated that the partition tendency of PAHs to plant tissues was similar with that to organic Cenriched humin. The contribution of absorption of plant to PAHs remediation, however, can be neglected comparing with that of soil. In conclusion, rhizosphere poses a vital contribution to PAHs remediation in soil, especially when evaluating with toxicity risk.
KeywordsNon-extractable PAHs Rhizoremediation Sequential solvent extraction Toxicity equivalence factors (TEFs)
Unable to display preview. Download preview PDF.