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Updated: Jun 18, 2026

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Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films
Published on: November 9, 2015
Radionuclides in mono lake, california
Summary
Mono Lake
Area of Science:
- Environmental chemistry
- Radiochemistry
- Geochemistry
Background:
- Naturally occurring uranium and thorium decay series radioisotopes and fallout plutonium exhibit elevated concentrations in Mono Lake's water column.
- Mono Lake is characterized as a natural alkaline and saline environment.
Purpose of the Study:
- To investigate the factors controlling the solubility and distribution of radioisotopes in Mono Lake.
- To understand the complexation behavior of actinide elements in alkaline, saline waters.
- To determine the removal and release rates of thorium from the water column to sediments.
Main Methods:
- Analysis of radioisotope concentrations in the water column.
- Assessment of actinide element complexation with carbonate ions.
- Evaluation of daughter/parent activity ratios for thorium, radium, and uranium isotopes.
Main Results:
- Unusually high concentrations of uranium, thorium, and plutonium radioisotopes were observed in Mono Lake water.
- Carbonate complexation enhances the solubility of actinide elements (oxidation states IV-VI).
- Strontium-90 was largely removed from the water column, likely via coprecipitation with calcium carbonate.
- Thorium removal to sediments occurs on timescales longer than one month, with desorption to water requiring less than a few years.
Conclusions:
- Carbonate complexation is a key factor in the high solubility of actinides in Mono Lake.
- Differential removal mechanisms affect various radioisotopes, with strontium-90 being efficiently removed.
- Thorium exhibits significant residence time in the sediments, with relatively rapid desorption kinetics.
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