99Tc in the sub-arctic food chain Lichen-Reindeer-man |
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| Institution: | 1. Department of Mathematics and Physics, University of Campania Luigi Vanvitelli, Caserta, Italy;2. Fukushima Environmental Evaluation Research Division, Japan Atomic Energy Agency (JAEA), Japan;3. Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy;4. Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency (JAEA), Japan;1. Department of Chemistry and Pharmaceutical Sciences, University of Trieste, Via Licio Giorgieri, 1, I-34127, Trieste, Italy;2. Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Unidad Asociada ULPGC-CSIC, Parque Científico Tecnológico Marino de Taliarte S/n, E-35214, Telde, Las Palmas, Spain;3. Department of Life Sciences, University of Trieste, Via Licio Giorgieri, 10, I-34127, Trieste, Italy;4. Geosciences Environment Toulouse (GET), CNRS, UMR 5563, Observatoire Midi-Pyrénées, 14 Avenue Edouard Belin, F-31400, Toulouse, France;5. N. Laverov Federal Center for Arctic Research, URoRAS, 23 Naberezhnaja Sev. Dviny, 163000, Arkhangelsk, Russia;6. BIO-GEO-CLIM Laboratory, Tomsk State University, Lenina Prs 36, Tomsk, Russia;1. Department of Medical Radiation Physics, Lund University, Barngatan 2, SE-22185 Lund, Sweden;2. Norwegian Radiation Protection Authority, PO Box 55, NO-1332 Østerås, Norway;3. Department of Radiation Physics, Sahlgren Academy, University of Gothenburg, SE-41345 Gothenburg, Sweden |
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| Abstract: | The deposition, migration and annual variations of 99Tc fallout in carpets of lichen collected during the period 1956–1981 have been investigated. The transfer of 99Tc to reindeer and man has also been studied. Technetium showed a shorter mean residence time than 137Cs in the lichen carpet. The activity ratio 99Tc/137Cs was generally lower than the theoretical fission ratio of 1·43 × 10−4. The maximum concentration of 99Tc in lichens occurred in 1967 (ca. 60 mBq kg−1) but in 1975 higher values were found than would have been predicted from fallout. The average depth integrated concentration of 99Tc at 62·3°N, 12·4° E in 1972 was 540 ± 100 mBq m−2. The studies of reindeer tissues show that technetium has a short mean residence time in the muscle tissues (ca. 5 days) and is not accumulated like 137Cs. The committed dose equivalent from 99Tc to the local Lapp population engaged in reindeer breeding is negligible. |
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