土壤中多环芳烃生物有效性及其评价方法(英文)

Bioavailability of polycyclic aromatic hydrocarbons in soils and its evaluation method

多环芳烃(PAHs)是中国土壤中广泛存在的一类具有致癌、致畸、致突变等危害的持久性有机污染物,其在环境中降解缓慢,具有生物累积性,并可通过食物链传递、放大,对人体健康构成很大威胁,因此迫切需要开展其生物有效性及生态风险相关研究.本文研究了农田污染土壤中14种中到高疏水性PAHs在植物体内的吸收、累积及从根部向茎叶部分的传输.结果表明中到高疏水性的有机污染物如PAHs可在植物体内发生从根向茎叶的传输,向茎叶传输的量与化合物的疏水性之间存在显著的线性定量关系;同时,一种新型半渗透膜采样装置——三油酸甘油酯-醋酸纤维素复合膜(TECAM)被成功地应用于土壤中PAHs的采集及其对植物(Triticum aestivumL.)和蚯蚓(Eisenia andrei)的生物有效性,结果表明:TECAM对土壤中PAHs的采样可在48h内达到表观平衡,大大缩短了土壤中有机污染物的采样时间;TECAM可反映PAHs在土壤中的残留时间、土壤有机质及溶解有机碳含量对PAHs生物有效性的影响;TECAM内PAHs浓度与蚯蚓体内浓度存在显著的线性相关关系;与化学提取方法相比,TECAM采集的PAHs不仅在浓度上与小麦根中浓度存在显著线性相关关系,而且TECAM采集的PAHs量也与小麦根富集的量相当;进一步提出了"土壤-孔隙水-TECAM"三室模型,并成功地描述了TECAM采集土壤中PAHs的三相平衡过程;此外,TECAM采样对土壤扰动小,操作简单,因此是采集土壤中有机污染物以及评价土壤中有机污染物生物有效性的有效方法.

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 fieldcontaminated 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 process 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.