The Hydrogeology Group examines the quality and quantity of water resources in the world today with emphasis on solving the environmental problems caused by ever-increasing human stress on hydrolic systems.

Dr. Shangping Xu
Specializing in colloid filtration in both saturated and unsaturated soil; transport and fate of colloid-bound emerging contaminants on a watershed scale; as well as behavior and toxicity of nanoparticles in the environment.
Research: My primary research interest lies in the protection of water resources and the supply of safe drinking water. Anthropogenic activities have profoundly altered the hydrological cycle and water qualities on local, regional and global scales. My research group aims at improving our understanding of the transport and fate of colloid-sized particles (mineral particles, particulate organic matter, bacteria and protozoa) as well as colloid-bound contaminants in both natural subsurface environments and engineered systems (i.e. drinking water treatment facility). Our current research projects include:
- Steric trapping of colloid-sized particles in physically and chemically heterogeneous porous media.
- Filtration behavior of pathogenic bacteria in both saturated and unsaturated porous media.
- Transport and fate of colloid-bound emerging contaminants on a watershed scale.
- Roles of wetland systems in flood control and water quality improvement.
- Behavior and toxicity of nanoparticles in the environment.
- Innovative techniques for drinking water purification and wastewater treatment.
- Shangping Xu’s Faculty Profile

Dr. Charles Paradis
Specializing in fate, transport, and remediation of contaminants in the environment; mobility of redox-sensitive radionuclides and metals in groundwater; field-based tracer experiments for characterization of hydraulic parameters and processes; method development for conducting and interpreting data from single-well push-pull tests.
Research: My research is typically experimental, field based, and focused on water quality. However, since joining the faculty at UWM in 2019, I have focused on experimental research that is lab based and includes batch sorption and one-dimensional flow through column tests with groundwater tracers in various types of natural and engineered granular and fractured media. I have recently gained a strong interest in virus transport in groundwater due to the often mysterious occurrences of human and animal enteric viruses in deep and confined aquifers; how did they get there? I have in the past and will likely continue to conduct research on the mobility of uranium in groundwater by working with the United States Department of Energy’s Office of Legacy Management, Los Alamos National Lab, and Oak Ridge National Lab. One of the biggest challenges with uranium-contaminated groundwater is understanding and predicting the mobility of uranium as a function of geochemical parameters such as: pH, alkalinity, organic carbon, and mineralogy. I encourage potential graduate students and post-docs to contact me directly via e-mail or phone if they are interested in joining my research group at UWM.