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Title: Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

Technical Report ·
DOI:https://doi.org/10.2172/1054161· OSTI ID:1054161
 [1];  [1];  [2];  [2];  [3];  [3];  [4];  [4];  [5];  [6]
  1. Univ. of Arizona, Tucson, AZ (United States)
  2. Pennsylvania State Univ., University Park, PA (United States)
  3. Univ. of California, Merced, CA (United States)
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  6. Univ. of Georgia, Athens, GA (United States)

Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.

Research Organization:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
DOE Contract Number:
FG02-08ER64615
OSTI ID:
1054161
Report Number(s):
DOE/ER/64615
Country of Publication:
United States
Language:
English