Uranium(VI) speciation in natural occurring water samples at pH 3 – 4, determined by TRLFS


Uranium(VI) speciation in natural occurring water samples at pH 3 – 4, determined by TRLFS

Baumann, N.; Arnold, T.

Knowledge in speciation is a requirement in investigations about migration paths of heavy metal con-taminations in the natural environment. A very helpful tool with an extremely low detection limit for analyzing speciation of certain radioactive heavy metal ions like uranium (VI) is the Time-resolved Laser-induced Fluores-cence Spectroscopy (TRLFS). This technique is particularly useful for detection of speciation from those ions in very low, but environmental relevant concentrations. So TRLFS can be useful in safety assessment concerning migration behaviour of fluorescent and radioactive elements.
In this study, TRLFS was applied to determine the uranium speciation in natural occurring seepage water sam-ples, and in soil water samples, all samples collected from test site “Gessenwiese” close to Ronneburg in Eastern Thuringia (Germany), were analyzed by TRLFS. This test site was installed as part of a research program of the Friedrich Schiller University Jena for investigations within the area of recultivated former uranium mining heaps.
The TRLFS measurements on water samples collected within test site Gessenwiese revealed that the uranium speciation in these seepage waters and soil waters is dominated by the hydrolyzed and monomer uranium (VI) sulfate species UO2SO4(aq). The analysis were based on the position of the peak maxima from the fluorescence signal, and their mono-exponential decay curve. Despite of the presence of high amounts of well-known fluores-cence quenchers like iron (up to 18.3 ppm) and manganese (up to extend of 97.4 ppm), the obtained uranium (VI) fluorescence signals from the natural surface and soil water samples showed sufficiently high intensity and thus could be analysed.
The here presented results are a convincing example for the suitability of TRFLS in analyzing the speciation of uranium from natural occurring water samples with pH values between 3.2 and 4.0. They were published in [1] and via Open Access.

Reference:

[1] N. Baumann, T. Arnold and M. Longschinski, J Radioanal Nucl Chem, accepted Aug. 2011

  • Contribution to proceedings
    10. Jenaer Sanierungkolloquium, 04.-06.10.2011, Dornburg, Deutschland
    Konferenzband zum 10. Jenaer Sanierungskolloquim

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Publ.-Id: 16044