Iodine-129, Iodine-127 and Cesium-137 in seawater from the North Sea and the Baltic Sea

In this study, new data are presented for the iodine isotopes (¹²⁷I, ¹²⁹I and their isotopic ratios) and Cesium (¹³⁷Cs) 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. ¹³⁷Cs in seawater was determined after cesium ion exchange procedure enrichment by gamma-spectrometry. The concentrations of ¹²⁷I 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 ¹²⁹I concentrations in these areas were detected, which decreased along the French, Belgian, Dutch, German, and Danish shores. ¹²⁹I/¹²⁷I 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 ¹²⁹I 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 ¹²⁹I. In 2009, the activity concentration of ¹³⁷Cs 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 ¹³⁷Cs 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 ¹²⁹I/¹²⁷I atomic ratio in the environmental compartments.

Retrospective dosimetry of Iodine-131 exposures using Iodine-129 and Caesium-137 inventories in soils--A critical evaluation of the consequences of the Chernobyl accident in parts of Northern Ukraine

The radiation exposure of thyroid glands due to (131)I as a consequence of the Chernobyl accident was investigated retrospectively based on (129)I and (137)Cs inventories in soils in Northern Ukraine. To this end, soil samples from 60 settlements were investigated for (129)I, (127)I, and (137)Cs by AMS, ICP-MS and gamma-spectrometry, respectively. Sampling was performed between 2004 und 2007. In those parts of Northern Ukraine investigated here the (129)I and (137)Cs inventories are well correlated, the variability of the individual (129)I/(137)Cs ratios being, however, high. Both the (129)I and (137)Cs inventories in the individual 5 samples for each settlement allowed estimating the uncertainties of the inventories due to the variability of the radionuclide deposition and consequently of the retrospective dosimetry. Thyroid equivalent doses were calculated from the (129)I and the (137)Cs inventories using aggregated dose coefficients for 5-year old and 10-year-old children as well as for adults. The highest thyroid equivalent doses (calculated from (129)I inventories) were calculated for Wladimirowka with 30 Gy for 5-years-old children and 7 Gy for adults. In 35 settlements of contamination zone II the geometric mean of the thyroid equivalent doses was 2.0 Gy for 5-years-old children with a geometric standard deviation (GSD) of 3.0. For adults the geometric mean was 0.47 Gy also with a GSD of 3.0. In more than 25 settlements of contamination zone III the geometric means were 0.82 Gy for 5-years old children with a GSD of 1.8 and 0.21 Gy for adults (GSD 1.8). For 45 settlements, the results of the retrospective dosimetry could be compared with thyroid equivalent doses calculated using time-integrated (131)I activities of thyroids which were measured in 1986. Thus, a critical evaluation of the results was possible which demonstrated the general feasibility of the method, but also the associated uncertainties and limitations.

Iodine-129, iodine-127 and caesium-137 in the environment: soils from Germany and Chile

Soil profiles from Bavaria in southern Germany and from Chile were analysed for (129)I by accelerator mass spectrometry (AMS), for (127)I by inductively coupled plasma mass spectrometry (ICP-MS), and for (137)Cs by gamma-spectrometry. The mean deposition density of (137)Cs in soils from Bavaria was (41×1.5(±1)) kBq m(-2) (geometric mean and geometric standard deviation), originating mostly from the Chernobyl fall-out. The deposition density of (129)I in these soils was (109×1.5(±1)) mBq m(-2). The dominant sources of (129)I in Bavaria are, however, the reprocessing plants La Hague and Sellafield and not the Chernobyl fall-out. The (129)I/(127)I isotopic ratios of the Bavarian soils were between 10(-7) and 10(-10), i.e. 10(2)-10(5) times higher than the ratios observed for the samples from Chile. The (129)I integral deposition densities in Chile, Easter Island and Antarctica were between 0.3 mBq m(-2) and 2 mBq m(-2). In these soils, the observed (129)I/(127)I ratios were about 10(-12). The soils from Chile allow the determination of the (129)I fall-out from the atmospheric nuclear weapons explosions undisturbed from contaminations due to releases from reprocessing plants. An upper limit of the integral (129)I deposition density of the atmospheric nuclear weapons explosions on the Southern Hemisphere (27°S) is about 1 mBq m(-2). Finally, the dependence of the migration behaviour of (137)Cs, (127)I and of (129)I on the soil properties is discussed. It turns out that there is a distinctly different behaviour of (127)I, (129)I, and (137)Cs in the soils exhibiting different sorption mechanisms for old and recent iodine as well as for (137)Cs.

Iodine-129 and iodine-127 in European seawaters and in precipitation from Northern Germany

In order to obtain a comprehensive survey on the consequences of the marine (129)I discharges from the European reprocessing plants La Hague and Sellafield, the distribution of (129)I and (127)I in surface waters of the North Sea, the English Channel, the Irish Sea, and the Northeast Atlantic was studied using accelerator mass spectrometry for (129)I and ICP-MS for (127)I. Samples of seawater were taken in the German Bight in May, September, and November 2005 and in the entire North Sea and the English Channel in August 2005. Further samples were obtained from the Irish Sea in June and August 2006 and from Arctic waters between Spitsbergen and Southern Norway in September 2005. (129)I is a conservative tracer in seawater. The concentrations of (127)I are relatively constant with exceptions of coastal areas with high biological activity and of areas influenced by influx from rivers and the Baltic Sea. The variability of the (129)I/(127)I isotopic ratios is exclusively determined by admixture of (129)I released from the reprocessing facilities Sellafield and La Hague to the seawater. The (129)I/(127)I ratios were between 4 × 10(-9)and 3 × 10(-6): at least 3 orders of magnitude higher than the natural equilibrium isotopic ratio 1.5 × 10(-12). (129)I/(127)I ratios of a few times 10(-10) were only found in seawater from the Indian Ocean and from the Pacific at Hawaii. Comparison of the results obtained for seawater with those of a measurement of airborne iodine species and with iodine isotopes in precipitation in Northern Germany demonstrates the transfer of (129)I and (127)I from the sea into the atmosphere and the dominating role of the marine discharges for the atmospheric fallout of (129)I in Western Europe. The results are discussed with the goal to estimate the relevance of the marine discharges for the contamination of the continental areas.

Continuous subcutaneous insulin infusion leads to immediate, stable and long-term changes in metabolic control

BACKGROUND

Evaluations of continuous subcutaneous insulin infusion (CSII) usually focus on one pre- and one post-CSII measurement to assess metabolic therapy outcome.

AIM

Extending this research, the aim of the present study was to provide a more fine-grained analysis of achieved glycaemic control.

METHODS

In 52 patients with type 1 diabetes (mean age of 37.85 years at CSII begin; s.d. +/- 12.41), haemoglobin A(1c) (HbA(1c)) levels were assessed every 3 months over a period of 5 years (1 year before and 4 years after the introduction of CSII). Mixed models were utilized to describe changes in glycaemic control.

RESULTS

The pre-post course showed that already in the first quarter, a statistically significant lower HbA(1c) level was obtained [7.30%, in contrast to 8.21% at the last quarter with intensified conventional therapy (ICT)]. In the following 15 quarters, the mean HbA(1c) levels remained constantly lower than that with ICT. Overall, the aggregated mean HbA(1c) level of patients with CSII therapy was 7.19%, in contrast to 8.08% with ICT; thus, an overall decrease by 11% was achieved. In addition, individual differences in blood glucose level and age of diabetes onset as a predictor for therapy success were analysed.

CONCLUSIONS

The data show an immediate, stable and long-term effect of CSII on HbA(1c). In addition, a significant relationship between metabolic control and age of diabetes onset was found, as well as a reduction of variance in HbA(1c) levels between subjects after change to CSII.