Quantifying Particulate and Colloidal Release of Radionuclides in Waste‐Weathered Hanford Sediments

Abstract

At the Hanford Site in the state of Washington, leakage of hyperalkaline, high ionic strength wastewater from underground storage tanks into the vadose zone has induced mineral transformations and changes in radionuclide speciation. Remediation of this wastewater will decrease the ionic strength of water infiltrating to the vadose zone and could affect the fate of the radionuclides. Although it was shown that radionuclide host phases are thermodynamically stable in the presence of waste fluids, a decrease in solution ionic strength and pH could alter aggregate stability and remobilize radionuclide-bearing colloids and particulate matter. We quantified the release of particulate, colloidal, and truly dissolved Sr, Cs, and I from hyperalkaline-weathered Hanford sediments during a low ionic strength pore water leach and characterized the released particles and colloids using electron microscopy and X-ray diffraction. Although most of the Sr, Cs, and I was released in dissolved form, between 3 and 30% of the Sr and 4 to 18% of the Cs was associated with a dominantly zeolitic mobile particulate fraction. Thus, the removal of hyperalkaline wastewater will likely induce Sr and Cs mobilization that will be augmented by particulate- and colloid-facilitated transport.

Tropical river suspended sediment and solute dynamics in storms during an extreme drought

“…Suspended sediment obtained on the filter membranes was analyzed by X-ray diffraction (XRD) and quantified using the Rietveld technique [Rietveld, 1967[Rietveld, , 1969 using the Rietveld module included in the Highscore Plus software following a previously published method [Perdrial et al, 2014[Perdrial et al, , 2015. Diffractograms were acquired on a Panalytical X'Pert equipped with a Cu K a X-ray tube and recorded between 5 and 7582H at a resolution of 0.00882H with a counting time of 179.705 s/step at the University of Pennsylvania.…”

Microbial cells can cooperate to resist high-level chronic ionizing radiation

“…Understanding CIR effects on biological systems is important for dealing with the consequences of occupational/medical exposures (nuclear industry workers, astronauts, radiotherapy patients), terrorist attacks involving radioactive materials, nuclear power plant accidents (Chernobyl, Fukushima), and often overlooked, the hazards of Cold War radioactive waste sites, including the Hanford facility [ 1 , 2 ]. Moreover, after decades of advances in space technology and propulsion, CIR in space has remained the most intractable, most severe, obstacle to planning manned Mars missions [ 3 , 4 ].…”