Tenax提取预测老化土壤中多环芳烃的生物有效性

利用聚2,6-二苯基对苯醚(poly(2,6-diphenyl-p-phenylene oxide),商品名Tenax-TA)提取来自9个老化农田土壤中的多环芳烃(PAHs),并应用Tenax-TA评价老化土壤中PAHs对赤子爱胜蚓(Eisenia Fetida)的生物有效性.结果表明,多年老化土壤中污染物的主要组成为4环以上的PAHs;蚯蚓较易富集低环PAHs,对高环PAHs富集能力较差;400h Tenax连续提取实验得出快速、慢速和极慢速吸附速率常数数量级分别为:10-1~10-2、10-2~10-3、10-4~10-6;而快速、慢速和极慢速解吸比率分别为0.02~0.27、0.01~0.33和0.40~0.95.Tenax 6h单点提取PAHs的量与蚯蚓体内PAHs富集量显著相关,表明6h Tenax对多年老化土壤中PAHs的提取量可以用来作为其生物有效性的评价方法.

The tenax extraction technique to predict the bioavailability of aged PAHs in soil

Tenax-TA was used to extract polycyclic aromatic hydrocarbons from 9 aged agricultural soils and to assess the PAHs bioavailability to earthworm (Eisenia Fetida). The results showed that the high molecular weight PAHs (≥ 4 rings) contributed the largest proportion to the contaminants in the long-term aged agricultural soils. Moreover, the light molecular weight PAHs could be susceptible to be accumulated in the earthworm, while the high molecular weight PAHs were hard to be accumulated. In the present study, PAHs desorption from the agricultural soils was investigated by Tenax extraction. The results of the Tenax consecutive extraction (400 h) indicated that the rate constants were in the order of 10-1~10-2, 10-2~10-3 and 10-4~10-6 and the corresponding fractions were 0.02~0.27, 0.01~0.33 and 0.40~0.95 for the rapid, slow and very-slow desorption, respectively. The fraction of PAHs extracted by Tenax for 6h correlated well with the amount accumulated in earthworms, indicating that Tenax 6 h-extracted fraction could serve as a good predictor of PAHs bioavailability to earthworm.