Plant Science Center, Department of Agronomic and Forestry Sciences, Universidade Federal Rural do Semi-Árido (UFERSA), Av. Francisco Mota, 572, Costa e Silva, Mailbox: 137, Mossoró, Rio Grande do Norte, CEP 59625-900, Brazil.
Environ Sci Pollut Res Int. 2022 Feb;29(10):15127-15143. doi: 10.1007/s11356-021-16644-x. Epub 2021 Oct 9.
Herbicide mixtures have often been used to control weeds in crops worldwide, but the behavior of these mixtures in the environment is still poorly understood. Laboratory and greenhouse tests have been conducted to study the interaction of the herbicides diuron, hexazinone, and sulfometuron-methyl which have been applied alone and in binary and ternary mixtures in the processes of sorption, desorption, half-life, and leaching in the soil. A new index of the risk of leaching of these herbicides has also been proposed. The sorption and desorption study has been carried out by the batch equilibrium method. The dissipation of the herbicides has been evaluated for 180 days to determine the half-life (t). The leaching tests have been carried out on soil columns. The herbicides isolated and in mixtures have been quantified using ultra-high performance liquid chromatography coupled to the mass spectrometer. Diuron, hexazinone, and sulfometuron-methyl in binary and ternary mixtures have less sorption capacity and greater desorption when compared to these isolated herbicides. Dissipation of diuron alone is slower, with a half-life (t) = 101 days compared to mixtures (t between 44 and 66 days). For hexazinone and sulfometuron-methyl, the dissipation rate is lower in mixtures (t over 26 and 16 days), with a more pronounced effect in mixtures with the presence of diuron (t = 47 and 56 and 17 and 22 days). The binary and ternary mixtures of diuron, hexazinone, and sulfometuron-methyl promoted more significant transport in depth (with the three herbicides quantified to depth P4, P7, and P7, respectively) compared to the application of these isolated herbicides (quantified to depth P2, P4, and P5). Considering the herbicides' desorption and solubility, the new index proposed to estimate the leaching potential allowed a more rigorous assessment concerning the risk of leaching these pesticides, with hexazinone and sulfometuron-methyl presenting a higher risk of contamination of groundwater.
除草剂混合物在全球范围内常用于控制作物杂草，但这些混合物在环境中的行为仍知之甚少。已进行实验室和温室测试，以研究在单独以及二元和三元混合物形式下应用的除草剂敌草隆、六嗪酮和甲磺隆的相互作用，这些除草剂在土壤中的吸附、解吸、半衰期和淋滤过程中进行了研究。还提出了一种新的这些除草剂淋滤风险指数。通过批量平衡法进行吸附和解吸研究。评估了 180 天内除草剂的消解，以确定半衰期（t）。在土壤柱上进行了淋滤测试。使用超高效液相色谱-质谱联用仪对分离和混合的除草剂进行了定量。与单独的这些除草剂相比，敌草隆、六嗪酮和甲磺隆在二元和三元混合物中的吸附能力较低，解吸能力较强。敌草隆单独消解较慢，半衰期（t）=101 天，而混合物（t 在 44 至 66 天之间）。对于六嗪酮和甲磺隆，混合物中的消解速率较低（t 超过 26 和 16 天），在存在敌草隆的混合物中表现出更明显的效果（t = 47 和 56 以及 17 和 22 天）。与单独施用这些除草剂相比（分别定量到 P2、P4 和 P5 深度），敌草隆、六嗪酮和甲磺隆的二元和三元混合物更促进了更深的深度运输（分别定量到 P4、P7 和 P7 深度）。考虑到除草剂的解吸和溶解度，所提出的新指数用于估计这些农药淋滤潜力，可更严格地评估这些农药淋滤的风险，六嗪酮和甲磺隆具有更高的地下水污染风险。
