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Immobilization and interactions of Tc and I in the subsurface and mechanisms controlling their retention

EMSL Project ID


The vadose zone at the Hanford site represents a continuous source of radioactive and other contaminants to groundwater through flux created by recharge from precipitation. This project will utilize Environmental and Molecular Sciences Laboratory (EMSL) capabilities to characterize potential capillary fringe treatment technologies to intercept radionuclides (Tc-99 and I-129) migrating from the vadose zone to the groundwater. Treatment technologies to be tested in batch experiments for their capacity to sequester Tc and I, using stable 127I as iodide (I-) or iodate (IO3-), include zero valent iron (ZVI), sulfur modified iron (SMI), and natural organic matter (NOM). The sequestration capability will also be tested in the presence of simulated natural factors such as calcite forming solutions and microbes. Following these tests the chemical state of the sequestered Tc and I, location of Tc and I and changes to the treatment materials will be investigated using a series of spectroscopic and microscopic techniques. This information will help build a mechanistic understanding of the remediation of Tc and I using these technologies and strengthen their case for deployment at the Hanford site.

Project Details

Start Date
End Date


Principal Investigator

Nikolla Qafoku
Pacific Northwest National Laboratory

Team Members

Robert Asmussen
Pacific Northwest National Laboratory

Amanda Lawter
Pacific Northwest National Laboratory

Related Publications

Lawter AR, N Qafoku, RM Asmussen, RK Kukkadapu, O Qafoku, DH Bacon, and CF Brown. 2018. "Element mobilization and immobilization from carbonate rocks between CO2 storage reservoirs and the overlying aquifers during a potential CO2 leakage." Chemosphere 197:399-410. doi:10.1016/j.chemosphere.2017.12.199