Mobility of Aqueous and Colloidal Neptunium Species in Field Lysimeter Experiments

Kathryn M. Peruski, Melody Maloubier, Daniel I. Kaplan, Philip M. Almond, Brian A. Powell

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Due to its radiotoxicity, long half-life, and potentially high environmental mobility, neptunium transport is of paramount importance for risk assessment and safety. Environmental transport of neptunium through field lysimeters at the Savannah River Site was observed from both oxidized (Np(V)) and reduced (Np(IV)) source materials. While transport from oxidized neptunium sources was expected, the unexpected transport from reduced neptunium sources spurred further investigation into transport mechanisms. Partial oxidation of the reduced neptunium source resulted in significant release and transport into the mobile aqueous phase, though a reduced colloidal neptunium species appears to have also been present, enhancing neptunium mobility over shorter distances. These field and laboratory experiments demonstrate the multiple controls on neptunium vadose zone transport and chemical behavior, as well as the need for thorough understanding of radionuclide source terms for long-term risk prediction.

Original languageEnglish
Pages (from-to)1963-1970
Number of pages8
JournalEnvironmental Science and Technology
Volume52
Issue number4
DOIs
StatePublished - Feb 20 2018
Externally publishedYes

Funding

Soil and source analysis along with model development is based upon work supported by the U.S. Department of Energy (DOE) Office of Science, Office of Basic Energy Sciences and Office of Biological and Environmental Research under Award Number DE-SC-00012530. Effluent analysis is based upon work supported by Savannah River Remediation under project SRRA021685SR. SRNL personnel also receive support through contract DE-AC09-08SR22470 with the DOE. XAS experiments were all performed at the Stanford Synchrotron Radiation Lightsource (Beamline 11.2), which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.

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