An evidence of chemically and physically mediated migration of 238U and its daughter isotopes in the vicinity of a former uranium mine
| Autor: | Pascale Blanchart, Marie-Odile Gallerand, Arnaud Mangeret, Xavier Amet, Charlotte Cazala, Gilles Alcalde |
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| Přispěvatelé: | Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut de Radioprotection et de SÃreté Nucléaire, IRSN |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
geography
geography.geographical_feature_category 010504 meteorology & atmospheric sciences Isotope Activity ratios Health Toxicology and Mutagenesis food and beverages Wetland General Medicine 010501 environmental sciences Contamination 01 natural sciences Pollution Uranium mine 13. Climate action Environmental chemistry Radioactive contamination [SDE]Environmental Sciences Environmental Chemistry Environmental science Nuclide Dose rate Waste Management and Disposal 0105 earth and related environmental sciences |
| Zdroj: | Journal of Environmental Radioactivity Journal of Environmental Radioactivity, Elsevier, 2018, 195, pp.67-71. ⟨10.1016/j.jenvrad.2018.08.018⟩ |
| ISSN: | 0265-931X 1879-1700 |
| Popis: | International audience; The present study reports the evidence of a radioactive contamination in a wetland located downstream from a former French U mine in Brittany. This situation is demonstrated according to the measurements of gamma dose rates and activity ratios of 238U and 232Th-decay series nuclides, which give the justification regarding the accumulation of significant amounts of 238U, 230Th and 226Ra in this wetland. The dose rate map highlights an increase of radiation level along the former mine water pathway compared to the background value, with a maximum value of 1500 nSv.h−1 reached in the wetland. Activities of 238U, 230Th and 226Ra and 232Th/238U ratios measured in surface wetland soils are significantly higher than the geochemical background. 230Th/238U ratios less than unity suggest a preferential accumulation of U in the wetland, compared to its daughter isotopes. Moreover, the loss of 226Ra compared to 230Th raises its higher mobility compared to its parent isotope. In far-field sediments, 226Ra/238U ratio of 1.76 implies a different geochemical behavior of U, which could be explained by the occurrence of mobile U species. The results suggest that contamination of wetland soils and far-field sediments could result from discharges of underground mine waters. © 2018 Elsevier Ltd |
| Databáze: | OpenAIRE |
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