Dissipation, adsorption, and transport of cinmethylin in four types of soil

To study the dissipation, adsorption, and mobility characteristics of cinmethylin in soil, the soils from four representative crop-cultivation regions, characterized by fluvo-aquic soil, brown soil, black soil, and red loam, were selected for investigation. The dissipation, adsorption and mobility behaviors of cinmethylin in soils were systematically investigated by using shock equilibrium and soil thin-layer chromatography. The results showed that the dissipation of cinmethylin in four soil types followed a first-order kinetic equation, with half-lives ranging from 47.2 to 443.2 d, in which anaerobic microorganisms, organic matter content, and soil pH value were the most important factors regulating the dissipation of cinmethylin. The Elovich and Freundlich models were used to fit the data for adsorption and isothermal adsorption of cinmethylin, and the R² values were above 0.979. The Freundlich adsorption coefficients of cinmethylin in soils ranged from 0.30 to 3.76 (mg^1–n/(L·mg)). R_f ranged from 0.10 to 0.35 for red loam and brown soils and from 0.35 to 0.65 for fluvo-aquic soil and black soils, indicated that the mobility of cinmethylin in the four soils ranged from weak to moderately mobile. In summary, cinmethylin is a medium dissipation pesticide in all four soils, with highly adsorption and weak mobility in red loam and brown soils; in contrast, cinmethylin is weak adsorbed, moderate mobility, and the potential for contamination of groundwater systems is high in fluvo–aquic soil and black soil.