Mark Goltz is a well-known authority in the field of hydrogeology and subsurface contaminant transport and remediation. He is Distinguished Professor Emeritus of Engineering and Environmental Management at the Air Force Institute of Technology, where he conducted research into the fate and transport of groundwater contaminants and contaminated groundwater remediation technologies. He has published numerous works in these areas. Junqi Huang is a hydrologist in the Ground Water and Ecosystems Restoration Division, National Risk Management Research Laboratory, US EPA. He is an experienced hydrogeological modeler, with expertise developing models for groundwater flow and transport, groundwater management, and contaminated groundwater remediation strategies.