Leone P, Nègre M, Gennari M, Boero V, Celis R, Cornejo J
Università degli Studi di Torino, Dipartimento di Valorizzazione e Protezione delle Risorse Agroforestali, Chimica Agraria, Italy, Grugliasco.
J Environ Sci Health B. 2001 Mar;36(2):127-42. doi: 10.1081/PFC-100103739.
Adsorption of the imidazolinone herbicides imazapyr, imazethapyr and imazaquin was studied on two binary systems (ferrihydrite-humic acid) prepared by treating ferrihydrite (Fh) immediately after its precipitation with a soil humic acid (HA) at different loadings (4% and 8% HA content), and on a blank ferrihydrite sample prepared in the same way, but without HA addition. Imidazolinone adsorption on pure Fh and on the 4% Fh-HA decreased with increasing of the herbicide hydrophobicity (imazaquin<imazethapyr<imazapyr), whereas on the 8% Fh-HA system the order of adsorption was nearly the same, indicating that higher amounts of HA on Fh increase the hydrophobicity of the surface and thus increases its affinity for the herbicides, specially for imazaquin. Adsorption was also enhanced by low pH values and slight changes in pH enhanced the contribution of each component in adsorption. Both the nature of the surface exposed and its ability to interact with herbicides are greatly altered by the mutual interaction of Fh and HA. The results show that albeit artificial polyphasic associations are more representative of the real situation than single model components and are thus better indicators of the behaviour of a given herbicide in the soil.
研究了咪唑啉酮类除草剂咪草烟、灭草烟和咪唑喹啉酸在两种二元体系（水铁矿-腐殖酸）上的吸附情况。这两种二元体系是通过在水铁矿（Fh）沉淀后立即用不同负载量（腐殖酸含量为4%和8%）的土壤腐殖酸（HA）处理制备而成，同时还研究了以相同方式制备但未添加HA的空白水铁矿样品上的吸附情况。咪唑啉酮类除草剂在纯Fh和4% Fh-HA体系上的吸附量随除草剂疏水性增强（咪唑喹啉酸<灭草烟<咪草烟）而降低，而在8% Fh-HA体系上吸附顺序几乎相同，这表明Fh上更高含量的HA增加了表面疏水性，从而提高了其对除草剂的亲和力，特别是对咪唑喹啉酸的亲和力。低pH值也增强了吸附，pH值的轻微变化增强了各组分在吸附中的贡献。Fh和HA的相互作用极大地改变了暴露表面的性质及其与除草剂相互作用的能力。结果表明，尽管人工多相组合比单一模型组分更能代表实际情况，因此是给定除草剂在土壤中行为的更好指标。
