Event


Effects of Soil Heterogeneity and Time-Variable Hydrologic Systems on the Fate and Transport of Contaminants – The Critical Role of the Vadose Zone Processes

Christophe Darnault; Clemson University

Jan 27, 2017 at | 358 Hayden Hall

Geoscience Colloquium

 

 

Understanding the behavior of contaminants in the vadose zone, the area between the soil surface and the groundwater table, is critical for the protection of the environment and public health, the mitigation of their impacts, and the development of effective remediation procedures. The release of emerging contaminants, such as engineered nanomaterials, into the environment, the prevalence of microbial pathogens due to wildlife and agricultural activities in rural and agricultural watersheds, and the discharge of radionuclide wastes during storage, handling, and disposal of nuclear materials in groundwater systems are inevitable. To study the fate and transport of these contaminants in the vadose zone, we have investigated their mobility under different hydrodynamic and biogeochemical conditions found in the natural environment. We have demonstrated the critical role that preferential flow (macropore flow and fingered flow), transient in water content and velocity, transient in solution chemistry, gas-water interfaces, solid interfaces, system heterogeneities, and their interactions and feedback have in the transport and retention of contaminants in the vadose zone. The results of our research will contribute to the development and validation of fate and transport models of contaminants from pore scale to watershed scale for management and protection of groundwater resources, public health, ecosystem sustainability, risk assessment, and life-cycle analysis.