THE INFLUENCE OF REDOX CONDITIONS ON THE ENVIRONMENTAL BEHAVIOUR OF TECHNETIUM
Technetium is a man-made element of atomic number 43, having no stable isotope. Its concentration in the environment is continuously increasing, as a consequence of nuclear weapon testing in the atmosphere and releases from the nuclear fuel cycle. Another potential source of technetium to the environment is represented by nuclear waste disposal operations. On the basis of thermodynamic considerations, the anion pertechnetate (TcO-4**-) is the chemical form of technetium stable under pH and Eh conditions prevailing in terrestrial and aquatic environments: as such, technetium is very mobile and contamination is likely to occur on a global scale. Under anaerobic conditions, such as those found in anoxic soils and sediments, Tc(VII) may undergo reduction to Tc(IV): when in the 4+ oxidation state, technetium forms either insoluble compounds (TcS-2 and TcO-2) or complexes with a large number of organic substances. Therefore, the environmental mobility of technetium is modified under reducing conditions, which could determine the accumulation in anoxic soils and sediments. Further studies are required to evaluate both food chains contamination and toxic effects of relatively high concentrations of technetium on plants and living organisms.
Bibliographic Reference: XVTH MEETING OF THE EUROPEAN SOCIETY OF NUCLEAR METHODS IN AGRICULTURE, PIACENZA (ITALY), SEPT. 3-7, 1984 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31712 ORA
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Record Number: 1989123017300 / Last updated on: 1987-01-01
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