Iodine-129, Iodine-127 and Cesium-137 in seawater from the North Sea and the Baltic Sea. (October 2016)

• Record Type: Journal Article
• Authors: Daraoui, A.; Tosch, L.; Gorny, M.; Michel, R.; Goroncy, I.; Herrmann, J.; Nies, H.; Synal, H.-A.; Alfimov, V.; Walther, C.
• Is Part Of: Journal of environmental radioactivity. Volume 162/163(2016:Oct.)
• Page Start: 289
• Page End: 299
• Publication Date: 2016-10
• Subjects: Iodine-129 -- Isotopic ratios -- Environmental pathways -- Cesium-137 -- North Sea -- Baltic Sea -- AMS; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2016.06.006
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: In this study, new data are presented for the iodine isotopes ( 127 I, 129 I and their isotopic ratios) and Cesium ( 137 Cs) in water samples of the North Sea and the Baltic Sea in 2005 and 2009. This study supplements and extends the study of Michel et al. (2012). Iodine isotopes were separated from their matrix by using an anion exchange method and were determined by applying ICP-MS and AMS. 137 Cs in seawater was determined after cesium ion exchange procedure enrichment by gamma-spectrometry. The concentrations of 127 I in seawater of the North and Baltic Sea are fairly constant in each Sea with averages of (44 ± 2) and (21 ± 1) ng g −1, respectively, depending on the salinity. However, large variations of 129 I concentrations in these areas were detected, which decreased along the French, Belgian, Dutch, German, and Danish shores. 129 I/ 127 I isotope ratios in the Baltic Sea are about 10 times lower than in the North Sea in 2009. The highest isotopic ratios (2.7 × 10 −6 ) was detected in the English Channel east of the nuclear reprocessing plant at Cap de la Hague. The results confirm the result of our early study that the sources of 129 I in the North Sea are primarily the nuclear reprocessing facilities at Sellafield (UK) and La Hague (F), and that in the Baltic Sea the inflow of water from North Sea through the Danish Straits dominates the occurrence of 129 I. In 2009, the activity concentration of 137 Cs was at least 6 times higher in the Baltic Sea (37 Bq m −3 ) than in the North Sea (5.9 Bq m −3 ), due to release of 137 Cs from sediments in the Baltic Sea, which were contaminated by the Chernobyl accident and – to a minor degree – the atmospheric explosions of atomic bombs. The results are discussed by comparing the results of our previous work and the current study demonstrating the continuing disequilibrium of 129 I/ 127 I atomic ratio in the environmental compartments. Highlights: I-129 from European reprocessing plants drastically changed its natural abundances. The dominant sources of I-129 in the North Sea are the European reprocessing plants. The dominant sources of Cs-137 in the Baltic Sea are the Chernobyl accident in 1986. I-129 serves as radioactive tracer of the environmental iodine.