• Tuesday, June 16, 2026
• 9:00–10:30 a.m. PDT | 12:00–1:30 p.m. EDT | 17:00–18:30 BST
• Seminar cohosted by RemPlex and SURF
• Registration is open on Zoom

Monitored natural attenuation (MNA) of environmental contaminants in soils and groundwater relies on natural physical, chemical, and biological processes to reduce the risks associated with the contamination. These in situ, passive processes are monitored to track performance for meeting cleanup criteria over an expected timeline. Sometimes the natural processes are estimated (or observed) to not meet remedial objectives in a suitable time, so it may be appropriate to apply enhanced attenuation (EA) approaches to give the natural processes a little boost, for example, by improving degradation rates or facilitating mobility reduction. While the helping hand of EA typically requires a bit more activity than MNA, the approaches are intended to be a lighter, more sustainable approach than fully active remediation approaches, such as pump-and-treat.

“Enhanced Natural Attenuation: Pathways to Sustainable Remediation,” cohosted by the Center for Remediation of Complex Sites (RemPlex) and the Sustainable Remediation Forum (SURF), will explore specific EA technologies and approaches, their associated resource demands and impacts, and methodologies for evaluating and comparing the environmental footprint of different remediation approaches.

Attendees will gain insights into the following topics:

• an overview of approaches for monitoring and enhancing the natural attenuation of different contaminants of concern
• integrating green adsorbents and the need for multitechnology systems, real-time monitoring, and stakeholder engagement to ensure cost-effective, socially accepted solutions for contaminated sites
• the application of phytoremediation and a comparison with other remediation technologies.

Presenters

• Maria de Lurdes Dinis, professor, University of Porto
• Brian Looney, Savannah River National Laboratory
• Chris Gale, president, Applied Natural Sciences

Facilitators

• Evan Starr, U.S. Department of Transportation Volpe Center and at-large member, SURF Board of Trustees
• Katie Muller, RemPlex advisor, Pacific Northwest National Laboratory

About the Speakers

Dr. Maria de Lurdes Dinis is a professor in the Department of Mining Engineering at the University of Porto, Portugal. She holds a PhD and an MSc in environmental engineering from the University of Porto, as well as a five-year degree in mining engineering. With 25 years of experience in environmental issues related to radioactive contamination, her work focuses on the environmental impacts of uranium mining, environmental remediation, and sustainable approaches for the treatment of contaminated water. Currently, her research explores bio-based adsorbent materials, including Moringa oleifera seeds, for the removal of uranium from aqueous solutions, with an emphasis on environmentally responsible and cost-effective strategies for real-world applications. She has also collaborated with NATO and the IAEA for several years on capacity-building projects.

Abstract: Safe and sustainable treatment of uranium-contaminated water remains a pressing environmental challenge. This study explores the potential of green adsorbents as low-impact alternatives to conventional materials, focusing on crushed Moringa oleifera seeds and chitosan. Laboratory tests conducted under acidic conditions and at different uranium concentrations showed that Moringa oleifera seeds achieved removal efficiencies of up to 86%, particularly at higher concentrations and longer contact times, whereas chitosan was less effective under the same conditions. Under optimized conditions, the removal efficiency could be increased to 99%. These results underscore the promise of plant-based materials as cost-effective, environmentally responsible options for water remediation. Wider adoption, however, will require further optimization, pilot-scale validation, and clear communication of benefits to decision-makers, practitioners, and communities. Overall, the study supports the development of greener and more socially acceptable approaches to environmental remediation.

Mr. Chris Gale is president of Applied Natural Sciences, a company that specializes in phytoremediation. Mr. Gale has worked on dozens of phytoremediation systems across the United States and in the European Union. He has over 20 years of experience managing and implementing a wide variety of environmental site investigation, characterization, and remediation projects, including all aspects of building and leading successful teams on large-scale complex projects. Mr. Gale also has expertise with a variety of remedial technologies including in situ bioremediation, in situ chemical oxidation, in situ chemical reduction, in situ thermal treatment, soil vapor extraction, and dual-phase extraction.

Dr. Brian Looney is a research environmental engineer at Savannah River National Laboratory and an adjunct professor at Clemson University. For more than 40 years, he has coordinated applied research, development, and deployment for environmental characterization and clean-up methods. His work encompasses subsurface access techniques, remediation methods, and characterization tools, including horizontal drilling, bioremediation, and tracer testing. Currently, Dr. Looney supports technical activities related to attenuation-based remedies and he serves as a senior technical advisor supporting the DOE Environmental Management Program.