Mao Xinyu, Han Fengxiang X, Shao Xiaohou, Guo Kai, McComb Jacqueline, Arslan Zikri, Zhang Zhanyu
College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098 China.; Department of Chemistry and Biochemistry, Jackson State University, 1400 J. R. Lynch Street, P.O. Box 17910, Jackson, MS 39217, USA.
Department of Chemistry and Biochemistry, Jackson State University, 1400 J. R. Lynch Street, P.O. Box 17910, Jackson, MS 39217, USA.
Ecotoxicol Environ Saf. 2016 Mar;125:16-24. doi: 10.1016/j.ecoenv.2015.11.021. Epub 2015 Nov 30.
The objectives of this study were to investigate distribution and solubility of Pb, Cs and As in soils under electrokinetic field and examine the processes of coupled electrokinetic phytoremediation of polluted soils. The elevated bioavailability and bioaccumulation of Pb, As and Cs in paddy soil under an electro-kinetic field (EKF) were studied. The results show that the EKF treatment is effective on lowering soil pH to around 1.5 near the anode which is beneficial for the dissolution of metal(loid)s, thus increasing their overall solubility. The acidification in the anode soil efficiently increased the water soluble (SOL) and exchangeable (EXC) Pb, As and Cs, implying enhanced solubility and elevated overall potential bioavailability in the anode region while lower solubility in the cathode areas. Bioaccumulations of Pb, As and Cs were largely determined by the nature of elements, loading levels and EKF treatment. The native Pb in soil usually is not bioavailable. However, EKF treatment tends to transfer Pb to the SOL and EXC fractions improving the phytoextraction efficiency. Similarly, EKF transferred more EXC As and Cs to the SOL fraction significantly increasing their bioaccumulation in plant roots and shoots. Pb and As were accumulated more in plant roots than in shoots while Cs was accumulated more in shoots due to its similarity of chemical properties to potassium. Indian mustard, spinach and cabbage are good accumulators for Cs. Translocation of Pb, As and Cs from plant roots to shoots were enhanced by EKF. However, this study indicated the overall low phytoextraction efficiency of these plants.
本研究的目的是调查电动场作用下土壤中铅、铯和砷的分布及溶解度，并研究污染土壤电动强化植物修复的过程。研究了电动场（EKF）作用下稻田土壤中铅、砷和铯生物有效性和生物累积的提高情况。结果表明，EKF处理能有效将阳极附近土壤pH值降低至1.5左右，这有利于金属（类金属）的溶解，从而提高其整体溶解度。阳极土壤的酸化有效增加了水溶性（SOL）和可交换态（EXC）的铅、砷和铯，这意味着阳极区域的溶解度增强且整体潜在生物有效性提高，而阴极区域的溶解度较低。铅、砷和铯的生物累积很大程度上取决于元素性质、负载水平和EKF处理。土壤中的原生铅通常不可生物利用。然而，EKF处理倾向于将铅转移到SOL和EXC组分中，提高植物提取效率。同样，EKF将更多的EXC砷和铯转移到SOL组分中，显著增加了它们在植物根和地上部分的生物累积。由于铅和砷的化学性质，它们在植物根中的累积量比地上部分多，而铯由于其与钾的化学性质相似，在地上部分的累积量更多。印度芥菜、菠菜和卷心菜是铯的良好累积植物。EKF增强了铅、砷和铯从植物根到地上部分的转运。然而，本研究表明这些植物的整体植物提取效率较低。
