Villaverde Jaime
Instituto de Recursos Naturales y Agrobiología (CSIC), Apdo 1052, 41080 Sevilla, Spain.
J Hazard Mater. 2007 Apr 2;142(1-2):184-90. doi: 10.1016/j.jhazmat.2006.08.005. Epub 2006 Aug 8.
High pesticide concentrations in soil from spills or discharges can result in point-source contamination of ground and surface waters. Cost-effective technologies are needed for on-site treatment that meet clean-up goals and restore soil function. Remediation is particularly challenging when a mixture of pesticides is present. beta-Cyclodextrins (BCD) solutions are employed to enhance the aqueous solubility of a hydrophobic organic compound. The interaction of norflurazon (NFL) with BCD yielded the formation of inclusion complexes at a 1:1 stoichiometric ratio in solution. The change of the sorption parameter K(d) as affected by the time, and desorption studies of NFL previously adsorbed on four different soils with different characteristics have been performed in the presence of 0.01 M BCD or 0.01 M Ca(NO(3))(2) acting as extractant solutions. NFL sorption increased with the residence time in soil, making it more resistant to be desorbed. Likewise, leaching experiments were performed in packed soil columns eluting initially with distilled water, with the aim to simulate the herbicide drainflow losses because of rainfall, approaching to a more realistic environment, and later with 0.01 M BCD solutions to extract the residual NFL bound. The results showed that removal efficiencies of the different flushing systems were significantly influenced by their affinity and selectivity for the contaminants in the soil matrix as well as BCD adsorption on soils, since this could act like a bridge between pesticide molecule and soil particles increasing the stay of NFL in soil. These results are further information to be in condition to predict the potential effect of the BCD solutions on soil chemical decontamination in the field situation assessing the likelihood for bioremediation of a pesticide contaminated-soil, since the increasing in hydrosolubility of the contaminants means the first step before microorganism uptaken.
来自泄漏或排放的土壤中高浓度农药会导致地下水和地表水的点源污染。需要具有成本效益的现场处理技术，以实现清理目标并恢复土壤功能。当存在多种农药混合物时，修复工作尤其具有挑战性。β-环糊精（BCD）溶液用于提高疏水性有机化合物的水溶性。在溶液中，去甲草净（NFL）与BCD以1:1化学计量比相互作用形成包合物。研究了时间对吸附参数K(d)的影响，并在0.01 M BCD或0.01 M Ca(NO₃)₂作为萃取剂溶液的情况下，对先前吸附在四种不同特性土壤上的NFL进行了解吸研究。NFL的吸附随在土壤中的停留时间增加，使其更难被解吸。同样，在填充土壤柱中进行淋溶实验，最初用蒸馏水洗脱，目的是模拟由于降雨导致的除草剂径流损失，接近更现实的环境，随后用0.01 M BCD溶液萃取残留的结合NFL。结果表明，不同冲洗系统的去除效率受其对土壤基质中污染物的亲和力和选择性以及BCD在土壤上的吸附的显著影响，因为这可以像农药分子和土壤颗粒之间的桥梁一样，增加NFL在土壤中的停留时间。这些结果为预测BCD溶液在田间情况下对土壤化学去污的潜在影响提供了更多信息，评估农药污染土壤生物修复的可能性，因为污染物水溶性的增加意味着微生物吸收之前的第一步。
