This session focuses on recent advances in understanding and predicting the transport and treatment of contaminants in the vadose, critical, and saturated zones. We invite studies on physicochemical and biological processes that govern a range of contaminants and amendments, including organics, metals, radionuclides, pathogens, and nanoparticles. Of particular interest are studies that focus on the challenges posed by NAPL, PFAS, and heavy-metals or other conditions that complicate the application of traditional remediation approaches. This session focuses on:

• laboratory investigations focusing on governing processes of transport and transformation.
• enhancement of our ability to predict and control subsurface contaminant fate and transport.
• demonstration of the design, optimization, and evaluation of remediation methods.
• field investigations at complex sites.
• challenges related to treatment of emerging contaminants.

This session fosters interactions across the contaminant hydrogeology community by integrating knowledge across investigation scales and highlights the state of the contaminant hydrogeology field and future directions.