Radionuclides in living organisms – Calorimetric determination of the radionuclide toxicity

Quantification of radionuclide transfer within the environment and to the food chain is required for the reliable human risk assessment. The uptake of radionuclides by plants is typically described phenomenologically by transfer factors. However, investigations on a molecular level are necessary to understand the underlying processes. We studied the interaction of U(VI) with canola cells (Brassica napus) focusing on the concentration-dependent impact of U(VI) on the cell metabolism. Isothermal microcalorimetry was used to monitor the metabolic heat flow of the cells, which was compared to the cell viability. The speciation of U(VI) in the medium was determined by time-resolved laser-induced fluorescence spectroscopy and thermodynamic modeling. The data reveal the correlation of U(VI) hydroxo species with metabolic heat release and general oxidoreductase on a quantitative toxicity scale [1].

[1] Sachs, S., Geipel, G., Bok, F., Oertel, J., Fahmy, K., Calorimetrically determined U(VI) toxicity in Brassica napus correlates with oxidoreductase activity and U(VI) speciation. Env. Sci. Technol. 51 (2017) 10843.