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Updated: Feb 20, 2026

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films
Published on: November 9, 2015
Detailed effects of particle size and surface area on 222Rn emanation of a phosphate rock
Gustavo Haquin1, Zohar Yungrais2, Danielle Ilzycer2
1Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev (BGU), Sede Boqer, Israel; Radiation Safety Department, Soreq Nuclear Research Center, Yavne, Israel.
Abstract:
The dependency of radon emanation on soil texture was investigated using the closed chamber method. Ground phosphate rock with a large specific surface area was analyzed, and the presence of inner pores, as well as a high degree of roughness and heterogeneity in the phosphate particles, was found. The average radon emanation of the dry phosphate was 0.145 ± 0.016. The emanation coefficient was highest (0.169 ± 0.019) for the smallest particles (<25 μm), decreasing to a constant value (0.091 ± 0.014) for the larger particles (>210 μm). The reduction rate followed an inverse power law. As expected, a linear dependence between the emanation coefficient and the specific surface area was found, being lower than predicted for the large specific surface area. This was most likely due to an increase in the embedding effect of radon atoms in adjacent grains separated by micropores. Results indicate that knowledge of grain radium distribution is crucial to making accurate emanation predictions.
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