Simulation of 2,4-d herbicide transport through the unsaturated zone using an analytical model

Abstract

Pesticide movement through the unsaturated zone of the subsurface environment is a complex process. Agricultural practices, soil properties, and climatic conditions among others, constitute the most important aspects to be considered. To simulate the transport and fate of the herbicide 2,4-D under real agricultural conditions, the Hantush–Mariño (1996) model has been applied. The model is a physically based analytical model that simulates pesticide transport in soils and groundwater. In the unsaturated zone, the model simulates one-dimensional pesticide movement based on the concept of complete mixing, adsorption, volatilization, and degradation. Linear equilibrium liquid–vapor partition is considered based on Henry's law and linear equilibrium adsorption is assumed for sorption and desorption in soil. The simulation model is applied to a study area located in a newly built golf course (Baix Emporda-Gerona, Spain), where 2,4-D is currently applied. Results show that with current agricultural practices, 2,4-D can be still detected at a depth of 2 m at concentrations greater than 0.1 µg/L.

Keywords:

• 2,4-D herbicide
• Simulation
• Herbicide transport
• Analytical model