Short-Term Iodine Dynamics in Soil Solution

Humphrey, Olivier S.; Young, Scott D.; Crout, Neil M.J.; Bailey, Elizabeth H.; Ander, E. Louise; Watts, Michael J.

Abstract

Assessing the reactions of iodine (I) in soil is critical to evaluate radioiodine exposure and understand soil-to-crop transfer rates. Our mechanistic understanding has been constrained by method limitations in assessing the dynamic interactions of iodine between soil solution and soil solid phase over short periods (hours). We use microdialysis to passively extract soil solution spiked with radioiodine (129I- and 129IO3-) to monitor short-term (≤40 h) in situ fixation and speciation changes. We observed greater instantaneous adsorption of 129IO3- compared to 129I- in all soils and the complete reduction of 129IO3- to 129I- within 5 h of addition. Loss of 129I from solution was extremely rapid; the average half-lives of 129I- and 129IO3- in soil solution were 4.06 and 10.03 h, respectively. We detected the presence of soluble organically bound iodine (org-129I) with a low molecular weight (MW) range (0.5-5 kDa) in all soils and a slower (20-40 h) time-dependent formation of larger MW org-I compounds (12-18 kDa) in some samples. This study highlights the very short window of immediate availability in which I from rainfall or irrigation remains in soil solution and available to crops, thus presenting significant challenges to phytofortification strategies in soil-based production systems.

Citation

Humphrey, O. S., Young, S. D., Crout, N. M., Bailey, E. H., Ander, E. L., & Watts, M. J. (2020). Short-Term Iodine Dynamics in Soil Solution. Environmental Science and Technology, 54(3), 1443-1450. https://doi.org/10.1021/acs.est.9b02296

• Journal Article Type: Article
• Acceptance Date: Jan 10, 2020
• Online Publication Date: Jan 10, 2020
• Publication Date: Feb 4, 2020
• Deposit Date: Feb 3, 2020
• Publicly Available Date: Jan 11, 2021
• Journal: Environmental science & technology
• Print ISSN: 0013-936X
• Electronic ISSN: 1520-5851
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 54
• Issue: 3
• Pages: 1443-1450
• DOI: https://doi.org/10.1021/acs.est.9b02296
• Keywords: General chemistry; Environmental chemistry
• Public URL: https://nottingham-repository.worktribe.com/output/3868082
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.est.9b02296
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science and Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.est.9b02296, see http://pubs.acs.org/page/policy/articlesonrequest/index.html].