Evaluation of Mobility and Sorption of Model Herbicidal Ionic Liquids with Dicamba Anion in Soil Matrix

This study was design to evaluate the mobility and sorption of a popular Dicamba herbicide in OECD and two different agricultural soils. The effect of structure modification by introducing cations of natural origin (betaine and choline) on sorption and migration of the herbicidal anion in the soil profile was also determined. Mobility evaluation of the analyzed compounds by TLC method showed a high potential for compound movement in the soil profile, which was further verified by sorption and leaching tests in glass columns. Sorption studies revealed that the presence of choline or betaine cation did not increased the amount of adsorbed Dicamba anion in the analyzed soils. Leaching studies conducted according to the OECD guide were incorporated in order to mimic the leaching of herbicidal ionic liquids in environmental conditions. Analysis of cation and anion in the leachate enabled to verify the stability and persistence of herbicidal ionic liquids in the soil. Obtained results support the hypothesis that cations and anions forming ionic liquids after introduction to environment perform as independent chemical molecules.