Karleuša Romano, Marinić Jelena, Tomić Linšak Dijana, Dubrović Igor, Antunović Domagoj, Broznić Dalibor
Department of Medical Chemistry, Biochemistry and Clinical Chemistry, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia.
Department for Health Ecology, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia.
Toxics. 2025 Mar 17;13(3):219. doi: 10.3390/toxics13030219.
Understanding the dynamics of sorption and desorption is essential for assessing the persistence and mobility of pesticides. These processes continue to influence ecological outcomes even after pesticide use has ended, as demonstrated by our study on dimethoate behavior in distinct soil samples from Croatia, including coastal, lowland, and mountainous regions. This study focuses on the sorption/desorption behavior of dimethoate in soil, explores the relationship between its molecular structure and the properties of soil organic and inorganic matter, and evaluates the mechanisms of the sorption/desorption process. The behavior of dimethoate was analyzed using a batch method, and the results were modeled using nonlinear equilibrium models: Freundlich, Langmuir, and Temkin models. Soils with a higher organic matter content, especially total organic carbon (TOC), showed a better sorption capacity compared to soils with a lower TOC. This is probably due to the less flexible structures in the glassy phase, which, unlike the rubbery phase in high TOC soils, do not allow dynamic and flexible binding of dimethoate within the organic matter. The differences between the H/C and O/C ratios indicate that in high TOC soils, flexible aliphatic compounds, typical of a rubbery phase, retain dimethoate more effectively, whereas a higher content of oxygen-containing functional groups in low TOC soils provides strong association. The lettered soils showed stronger retention of dimethoate through interactions with clay minerals and metal cations such as Mg, suggesting that clay plays a significantly more important role in enhancing dimethoate sorption than organic matter. These results highlight the importance of organic matter, clay, and metal ions in the retention of dimethoate in soil, indicating the need for remediation methods for those pesticides that, although banned, have had a long history of use.
了解吸附和解吸动力学对于评估农药的持久性和迁移性至关重要。正如我们对来自克罗地亚不同土壤样本（包括沿海、低地和山区）中乐果行为的研究所表明的那样，即使在农药使用结束后，这些过程仍会继续影响生态结果。本研究聚焦于乐果在土壤中的吸附/解吸行为，探究其分子结构与土壤有机和无机物质性质之间的关系，并评估吸附/解吸过程的机制。采用批量法分析乐果的行为，并使用非线性平衡模型（弗伦德利希模型、朗缪尔模型和坦金模型）对结果进行建模。与总有机碳（TOC）含量较低的土壤相比，有机物质含量较高的土壤表现出更好的吸附能力。这可能是由于玻璃态相中结构的灵活性较低，与高TOC土壤中的橡胶态相不同，玻璃态相不允许乐果在有机物质内进行动态和灵活的结合。H/C和O/C比率的差异表明，在高TOC土壤中，橡胶态相典型的柔性脂肪族化合物能更有效地保留乐果，而低TOC土壤中较高含量的含氧官能团则提供了更强的缔合作用。字母标记的土壤通过与粘土矿物和Mg等金属阳离子相互作用，对乐果表现出更强的保留作用，这表明粘土在增强乐果吸附方面所起的作用比有机物质显著更重要。这些结果凸显了有机物质、粘土和金属离子在土壤中保留乐果方面的重要性，表明对于那些虽已被禁用但有长期使用历史的农药，需要采用修复方法。
