Conceptual Model of Iodine Behavior in the Subsurface at the Hanford Site

Abstract

DOC Dissolved organic carbon DOE U.S. Department of Energy DPMAS Direct-polarization magic-angle spinning DWS Drinking water standard EXAFS Extended X-ray absorption fine structure spectra Eh Oxidation/reduction potential Stored in single-shell and double-shell tanks Discharged to liquid disposal sites (e.g., cribs and trenches) Released to the atmosphere during fuel reprocessing operations Captured by off-gas absorbent devices (silver reactors) at chemical separations facilities (PUREX, B-Plant, T-Plant, and REDOX)

Contaminant Attenuation and Transport Characterization of 200-DV-1 Operable Unit Sediment Samples from Boreholes C9497, C9498, C9603, C9488, and C9513

“…Note that for the purpose of evaluating iodine attenuation and transport behavior, this project used total iodine data because its concentration is above the method detection limit. The samples were also analyzed to determine the iodide and iodate concentrations in the sample because the transport properties of iodide and iodate are different (e.g., Zhang et al 2013;Truex et al 2016). Unfortunately, matrix interferences rendered determination of the speciation difficult, with results only reportable for two of the samples.…”

Identification of Promising Remediation Technologies for Iodine in the UP-1 Operable Unit

“…However, there are a few recently recorded groundwater concentrations that exceed 10 pCi/L (DOE 2017). Future plume behavior depends on fate and transport factors, including natural attenuation (Truex et al 2016). 129 I plume depictions over a 20-year period for the 200-UP-1 OU.…”

“…Iodine behavior in the subsurface is described by Truex et al (2016). This section summarizes this information to provide context for the assessment of remediation technologies.…”

“…Information on subsurface flow and transport parameters has also been compiled in a number of documents (e.g., DOE 2005DOE , 2012aFayer and Keller 2007;Last et al 2006Last et al , 2009. However, iodine transport is also potentially influenced by reactive facies related to reactions (e.g., few observed oxidation/reduction transformations, Truex et al 2016) and minimal iodide and iodate sorption (Xu et al 2015). The general facies of importance are redox minerals, organic material, carbonate, and microorganisms.…”

“…As shown in Figures 2 and 3, adsorption, transformations between species, associations with organic compounds, and precipitation are all important for iodine fate and transport. The processes shown in these figures are described in more detail by Truex et al (2016). Conceptual overview of subsurface biogeochemical processes that affect the fate and transport of iodine.…”