Tritium associé à la matière organique de sédiments, végétaux et poissons des principaux cours d'eau français

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Summary

Tritium levels in the organic matter of sediments, vegetation and fish were measured in 350 samples. The Rhône River, for example, is subject to no nuclear plant effluent (zone I), liquid effluents from nuclear power plants (zone II) and a reprocessing plant (zone III). The average concentration in sediment, in Bq · ^-1 of combustion water, is around 4500 in zone I, 2200 in zone II and 1800 in sone III. Average concentrations decrease too for mosses and are constant for emmerging vegetation. On the contrary, average concentrations in fish increase, with 80, 55 and 220 Bq · l^-1 of combustion water, respectively in the three zones. These results in comparison with those for other rivers, pose the questions of what is the tritium source in the environment and how it becomes fixed in organic matter.