Bioavailability of polycyclic aromatic hydrocarbons in soils and its evaluation method
土壤中多环芳烃生物有效性及其评价方法

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistant pollutants which are difficult to degrade and metabolize in the environment and exist widely around the world. They can accumulate in organisms and subsequently translocate, transform and be concentrated in food chain due to their lipophilicity. Some PAHs are carcinogenic and pose great risk to human health. In order to predict their potential risk, it is essential to explore the bioavailability of PAHs in soil. The uptake and acropetal translocation of 14 priority PAHs by wheat (Triticum aestivum L.) from field-contaminated soils has been investigated. The results indicate that compounds with intermediate to high hydrophobicity such as PAHs can acropetally translocate in plants. The amount of PAHs translocated from roots to aerial tissues has been quantified. Furthermore, a new type of semipermeable membrane-based passive sampler,triolein embedded cellulose acetate membrane (TECAM), was successfully applied to sample PAHs in soils. PAHs in soil sampled by TECAMs reached apparent equilibrium within 48h, significantly saving time for sampling PAHs in soil. The content of PAHs sampled by TECAMs was related to soil organic matter, dissolved organic carbon and the aging time of PAHs in soil. TECAM-accumulated PAHs correlated well with PAHs accumulated in earthworms (Eisenia andrei) and wheat roots (Triticum aestivum L.). Soil-pore water-TECAM three-compartment model was successfully used to describe the overall pro cess of PAH sampling by TECAM from field-contaminated soils. Additionally, TECAM caused minimal disturbance to soil and was easy to deploy. Therefore, TECAM is believed to be a useful tool to sampling hydrophobic organic carbons in soil and predict their bioavailability to earthworms and plants.