PNNL

Gemma Clark is a postdoctoral research associate in the Radiological Materials group at Pacific Northwest National Laboratory (PNNL). She joined PNNL in 2024 after earning her PhD in civil and environmental engineering from the University of Illinois Urbana-Champaign. Her research interests at PNNL include the degradation of nuclear waste forms, chemical fate and transport, groundwater remediation, and treatment of nuclear waste.

Before joining PNNL, her research examined chemical and microbiological drinking water quality, biofilm growth and characterization, stormwater reuse and microbial risk assessment, wastewater treatment, and electrochemical recycling of metals in mobile electronics. She has experience with a variety of experimental methods including DNA extraction, qPCR, flow cytometry, culture methods, quantitative microbial risk assessment, colorimetric methods for chemical measurements, total organic carbon, dynamic light scattering, inductively coupled plasma mass spectrometry, liquid–liquid extraction, optical coherence tomography imaging, aerosol measurements (optical particle sizer, scanning mobility particle sizer, cascade impactor), and statistical analyses. She also has experience with coding in R and Python.

• PhD in Civil & Environmental Engineering, University of Illinois Urbana-Champaign
• MS in Civil & Environmental Engineering, University of Illinois Urbana-Champaign
• BS in Civil & Environmental Engineering, University of Utah

• Lister, T.E., Parkman, J.A., Diaz Aldana, L.A., Clark, G.G., Dufek, E.J., Keller, P. “Reactor systems for recovering metals, and related methods.” U.S. Patent #11,035,023, issued June 15, 2021.
• Lister, T.E., Parkman, J.A., Diaz Aldana, L.A., Clark, G.G., Dufek, E.J., Keller, P. “Methods for recovering metals from electronic waste, and related systems.” U.S. Patent #10,378,081, issued August 13, 2019.
• Lister, T.E., Parkman, J.A., Diaz Aldana, L.A., Clark, G.G., Dufek, E.J., Keller, P. “Methods for recovering metals from electronic waste, and related systems.” U.S. Patent #9,777,346, issued October 3, 2017.

2026

• Clark, G.G., Coey, E.J., Loya, A.C., Nguyen, T.H. (2026) “A quantitative microbial risk assessment of activated carbon point-of-use filters and the risk Legionella pneumophila.” Water Res. (under review)
• Lawter, A.R., Clark, G.G., Escobedo, N., Bonnett, J., Canfield, N., Choi, S., Bowden, M.E., Matyas, J., Asmussen, R.M. (2026) “Semi-Dynamic Leach-Testing of Densified Silicon-Based Iodine Waste Forms” RSC Advances. 16(22) 19974-19990.

2025

• Asmussen, R.M., Clark, G.G., Anderson, J., Bourchy, A., Ferrer, J., Hossack, C., Lapeyre, J., Peterson, M., Rahmon, S.A., Reiser, J.T., Riley, B.J., Saslow, S.A., Silva, C. (2025) “A review of the Cast Stone formulation for nuclear waste immobilization” Waste Management. 211, 115277.
• Clark, G.G., Pan, W., Giammar, D.E., Nguyen, T.H. (2025) “Influence of biofilm and calcium on transport of lead phosphate nanoparticles through solid block activated carbon media” ACS ES&T Water. 5(11), 6927-6935.
• Clark, G.G., Zhang, G., Zhao, S., Nguyen, T.H. (2025) “Assessment of Legionella pneumophila in rural homes supplied by private well water” ACS ES&T Water. 5(2), 1041-1054.

2024

• Clark, G.G., Geisler, D., Coey, E.J., Pollitz, L.J., Zaki, F.R., Huang, C., Boppart, S.A., Nguyen, T.H. (2024) “Influence of phosphate on bacterial release from activated carbon point-of-use filters and on biofilm characteristics” Sci Total Environ. 914, 169932.

2023

• Huang, C., Ginn, T., Clark, G.G., Zaki, F.R., Won, J. Boppart, S.A., Nguyen, T.H. (2023) “Phosphate-based corrosion inhibition in drinking water systems and effects on disinfectant decay and biofilm growth” Environmental Engineering and Science. 40(11), 634-644.
• Huang, C., Clark, G.G., Zaki, F.R., Won, J., Ning, R., Boppart, S.A., Elbanna, A.E., Nguyen, T.H. (2023) “Effects of phosphate and silicate on stiffness and viscoelasticity of mature biofilms developed with simulated drinking water.” Biofouling. 1-11.

2022

• Shi, X., Clark, G.G., Huang, C., Nguyen, T.H., Yuan, B. (2022) “Chlorine decay and disinfection by-products formation during chlorination of biofilms formed with simulated drinking water containing corrosion inhibitors.” Sci Total Environ. 815, 152763.
• Clark, G.G., Pan, W., Giammar, D.E., Nguyen, T.H. (2022) “Influence of point-of-use filters and stagnation on water quality at a preschool and under laboratory conditions” Water Res. 211, 118034.

2020

• Oh, C., Araud, E., Puthussery, J.V., Bai, H., Clark, G.G., Wang, L., Verma, V., Nguyen, T.H. (2020) “Dry heat as a decontamination method for N95 respiratory reuse.” Environ Sci Technol Lett. 7, 677-682.

2019

• Clark, G.G., Jamal, R., Weidhaas, J. (2019) “Roofing material and irrigation frequency influence on microbial risk from consuming homegrown lettuce irrigated with harvested rainwater.” Sci Total Environ. 651, 1011-1019.

2018

• Fujita, Y., Reed, D., Walton, M., Clark, G., Vanzin, G., Salmon, O., Munakata-Marr, J. “Interactions of microorganisms and rare earth elements.” Muroran-IT Rare Earths Workshop, Nov. 2018.
• Clark, G.G., Weidhaas, J., Goel, R. “The effects of nanomaterials on E. coli growth.” Utah Conference on Undergraduate Research, Feb. 2018.

2017

• Diaz, L.A., Clark, G.G., Lister, T.E. (2017) “Optimization of the electrochemical extraction and recovery of metals from electronic waste using response surface methodology.” Ind Eng Chem Res. 56, 7516-7524.

2016

• Lister, T.E., Diaz, L.A., Clark, G.G., Keller, P. (2016) “Process development for the recovery of critical materials from electronic waste.” International Mineral Processing Congress, Sep. 11-15, 2016, Quebec City, Canada.
• Diaz, L.A., Lister, T.E., Parkman, J.A., Clark, G.G. (2016) “Comprehensive process for the recovery of value and critical materials from electronic waste.” J Clean Prod. 125, 236-244. Contributions to Presentations at Professional Conferences