Dollinger Jeanne, Dagès Cécile, Voltz Marc
INRA, UMR LISAH, 2 Place Pierre Viala, 34060, Montpellier, France.
Environ Sci Pollut Res Int. 2017 Apr;24(12):11752-11763. doi: 10.1007/s11356-017-8703-4. Epub 2017 Mar 23.
The performance of buffer zones for removing pesticides from runoff water varies greatly according to landscape settings, hydraulic regime, and system design. Evaluating the performance of buffers for a range of pesticides and environmental conditions can be very expensive. Recent studies suggested that the fluorescent dyes uranine and sulforhodamine B could be used as cost-effective surrogates of herbicides to evaluate buffer performance. However, while transformation mechanisms in buffers have been extensively documented, sorption processes of both dyes have rarely been investigated. In this study, we measured the adsorption, desorption, and kinetic sorption coefficients of uranine and sulforhodamine B for a diverse range of buffer zone materials (soils, litters, plants) and compared the adsorption coefficients (Kd) to those of selected herbicides. We also compared the global sorption capacity of 6 ditches, characterized by varying proportions of the aforementioned materials, between both dyes and a set of four herbicides using the sorption-induced pesticide retention indicator (SPRI). We found that both the individual Kd of uranine for the diverse buffer materials and the global sorption capacity of the ditches are equivalent to those of the herbicides diuron, isoproturon, and metolachlor. The Kd of sulforhodamine B on plants and soils are equivalent to those of glyphosate, and the global sorption capacities of the ditches are equivalent for both molecules. Hence, we demonstrate for the first time that uranine can be used as a proxy of moderately hydrophobic herbicides to evaluate the performance of buffer systems, whereas sulforhodamine B can serve as a proxy for more strongly sorbing herbicides.
缓冲带从径流水中去除农药的性能因景观设置、水力状况和系统设计的不同而有很大差异。评估一系列农药和环境条件下缓冲带的性能可能成本非常高。最近的研究表明，荧光染料尿酸和磺基罗丹明B可作为除草剂的经济有效替代物来评估缓冲带性能。然而，虽然缓冲带中的转化机制已有大量文献记载，但两种染料的吸附过程却很少被研究。在本研究中，我们测量了尿酸和磺基罗丹明B对多种缓冲带材料（土壤、凋落物、植物）的吸附、解吸和动力学吸附系数，并将吸附系数（Kd）与选定除草剂的吸附系数进行了比较。我们还使用吸附诱导农药滞留指标（SPRI）比较了6条沟渠（其特征为上述材料比例不同）对两种染料和四种除草剂组合的整体吸附能力。我们发现，尿酸对多种缓冲材料的个体Kd以及沟渠的整体吸附能力与除草剂敌草隆、异丙隆和异丙甲草胺相当。磺基罗丹明B在植物和土壤上的Kd与草甘膦相当，沟渠对这两种分子的整体吸附能力也相当。因此，我们首次证明尿酸可作为中等疏水性除草剂的替代物来评估缓冲系统的性能，而磺基罗丹明B可作为吸附性更强的除草剂的替代物。
