Unraveling the leaching of pesticide transport through porous media with an experimental and numerical study

The movement of solute or chemical species into the subsurface has been a concern of groundwater quality variation due to its hazardous and severe health-related effects. To understand and reliably predict the migration and fate of contaminants in the subsurface, modeling is necessary. In this study, the experiment is carried out to investigate the contaminant migration through porous media, particularly the solutes emerging through the pesticides. A soil column experiment is setup to trace the particles and their behavior is analyzed, which is validated using the numerical model. This model uses the advection-dispersion equation (ADE), taking the application of effective dispersivity in order to account for the local heterogeneity. The implicit finite difference technique has been incorporated into the numerical model. The implication of macrodispersivity provides a plentiful assay in delineating the transport process and a perspective for large-scale heterogeneities. Results exhibit the concentration profiles of pesticides in the function of depth and time that can be employed to identify the areas with higher contaminant loading in the groundwater, posing a severe threat to groundwater and human health. This necessitates the experimental and numerical model to predict the contaminant migration process and to lay down changes in policy-making, monitoring of harmful chemicals, adoption of good agricultural practices, and execution of water safety regulations which, in turn, can be incorporated in determining the emerging contaminants, PFASs, etc.,  in the groundwater.