NukSiFutur Young investigator group TecRad: Interactions of technetium with microorganisms, metabolites and at the mineral-water interface – Radioecological considerations.

Project. NukSiFutur Young investigators group TecRad: Interactions of technetium with microorganisms, metabolites and at the mineral-water interface – Radioecological considerations.

Funding source. German Federal Ministry of Education and Research (BMBF).

Duration: From 1.7.2022 to 30.06.2027

Grant number. Ref 02NUK072

Project sponsor: Projektträger Karlsruhe (PTKA).

Dr. Natalia Mayordomo Herranz works in the Surface Processes Department and since July 2022 is the leader of the NukSiFutur young investigators group TecRad.

Our Motivation

Technetium is an element whose all isotopes are radioactive, being technetium-99 (⁹⁹Tc) the most abundant. ⁹⁹Tc is one of the main fission products of uranium-235 and plutonium-239 and it will significantly contribute to radioactivity emitted by any spent nuclear fuel since ⁹⁹Tc has a long half-life (ca. 0.2 million years). Therefore, Tc needs to be considered in the long-term safety assessment of the nuclear waste repository. In addition, ⁹⁹Tc is the daughter isotope of metastable technetium-99 (^99mTc) the most worldwide used radioisotope for cancer diagnosis at hospitals. In this context, ⁹⁹Tc is daily discharged in wastewater although in low concentrations.

Environmental transport of Tc depends on the chemical conditions (e.g., pH, presence of ions, and redox potential), and it can drastically decrease when Tc is immobilized by reactive surfaces such as minerals or microorganisms. Therefore, it is relevant to study the immobilization mechanisms of Tc to develop technologies that help to protect the human being and the entire biosphere against Tc radio- and chemotoxicity.

Our approach

For a sound understanding of Tc biogeochemical behavior, our research will be approached from a multidisciplinary point of view, combining physical as well as radio-, geo- and biochemical methods. In particular, we focus on several advanced microscopic, electrochemical, and spectroscopic techniques to determine thermodynamic data of Tc in water or at the water-biogeochemical interfaces, that is derived on a molecular level. Furthermore, we aim at developing a new methodology for spectro-electrochemical experiments that can be further applied to other redox-active pollutants such as uranium, plutonium, selenium, arsenic, or chromium.

Our goals

Our goal is to study Tc behavior under more complex conditions, which could resemble environmental scenarios. Therefore, we will investigate how Tc interacts with microorganisms, metabolites, and minerals that are potentially present in the nuclear waste repository. First, Tc coordination is investigated in binary systems. Consequently, these data serve as models to study complex ternary or quaternary systems.

We will use the obtained thermodynamic data for development and parametrization of biogeochemical models. Until now, this has hardly been possible for redox-active systems such as plutonium, arsenic or selenium.

Team

Name	Bld./Office	+49 351 260	Email
Caroline Börner			c.boernerhzdr.de
Irene Cardaio	801/P254	2251	i.cardaiohzdr.de
Dr. Natalia Mayordomo Herranz	801/P252	2076	n.mayordomo-herranzhzdr.de
Vijay Kumar Saini	801/P352	3328	v.sainihzdr.de

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Selected Publikations

2023

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2022

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