Tritium and stable isotope (deuterium 2H and 18O) concentrations have been determined in natural waters collected from shallow lakes, wells, streams and rivers inside and in the vicinity of the former Semipalatinsk Nuclear Test Site (NE Kazakhstan). The Semipalatinsk Test Site (STS) was one of the main proving grounds for the testing of nuclear weapons by the former Soviet Union. Tritium activity concentrations have been determined by liquid scintillation counting, while hydrogen isotopic composition have been determined using a GV-Isoprime mass spectrometer coupled to an elemental analyzer. Tritium activity concentrations recorded in lake waters (in most cases >10 Bq L-1) were significantly higher than those in well, stream and the Irtysh River waters. In lake waters, enrichments in deuterium and 18O (δD and δ18O varying between –5 and –64 ‰ V-SMOW and –8.4 and +5.5 ‰ V-SMOW, respectively), and high salt concentrations, strongly suggest that significant evaporation has occurred. In contrast, deuterium and tritium signatures of ‘common’ surface and underground waters at the STS were mostly typical of present-day isotope backgrounds of natural waters in NE Kazakhstan. In STS, come salt lakes like Bajansor and Tumatsor with elevated tritium activity from 12 to 15 Bq L-1 lie close to the Global Meteoric Water Line. The potential tritium source for these lakes is residual concentration of tritium after former nuclear test in STS. The study provides evidence to show that export of tritium from underground nuclear test areas and tritium enrichment produced by evaporation are both important determinants of tritium concentrations in standing waters on the Semipalatinsk test site.

Radiocarbon levels were recorded in Fucus vesiculosus samples collected on a monthly basis over a three-year period at a site on the east coast of Ireland. The resulting data was analysed using a numerical model which estimates the transit times from the Sellafield plant to the sampling location, and the mean availability time of 14C in seaweed. With the inclusion of a model parameter allowing for seasonal variability in uptake by the Fucus, good correlation was observed between the predicted and measured concentrations. Future temporal trends of 14C Fucus concentrations along the eastern Irish coastline were modelled with the application of three possible prospective discharge scenarios, predicting 14C Fucus concentrations to reduce to ambient background levels within 2.5-years of discharges being set to zero. Such projections may prove helpful in assessing the consequences of discharge management and policy making in the context of the OSPAR convention.

Surface, intermediate and near-bottom water samples were collected at two of the North East Atlantic radioactive waste dumping sites (47 degrees 14'N, 05 degrees 33'W and 45 degrees 27'N, 06 degrees 16'W) in the course of a sampling campaign in June-July 1998. Analysis of (PU)-P-239,240 concentrations show no significant differences with respect to measured concentrations in waters taken from control (background) stations well removed from the dumping sites.

Time series of 137Cs and 99Tc activity concentrations in the brown seaweed Fucus vesiculosus and seawater, gathered at three locations on the eastern Irish coastline during the period 1988–2008, have been modelled using a novel approach incorporating a variable uptake rate in the seaweed. Seasonal variations in the time series, identified using spectral analysis, were incorporated into the model which was used to determine transfer kinetic parameters and to predict 137Cs and 99Tc concentrations in seaweed, as influenced by levels in ambient seawater. An optimisation method combining evolutionary and grid search minimisation techniques was adopted to determine the best values for the model parameters, from which concentration factors (CF) and biological half-lives (tb1/2) for 137Cs and 99Tc in F. vesiculosus were calculated. CF values of 170–179 and 1.1 × 105 l kg−1 (dry weight) were obtained for 137Cs and 99Tc, respectively, while the corresponding tb1/2 values were 39–47 and 32 days, respectively.

Development and testing of weapons of mass destruction may result in irreversible environmental changes resulting in high social risk and negative effects on human health. The former Semipalatinsk nuclear test site (STS) is a sorrowful monument of the Cold War. Nuclear tests at STS inflicted numerous economic, social and ecological problems on Kazakhstan. In the framework of the NATO "Science for Peace Program," about 1,400 km2 of the STS have been investigated. According to the results of the Semirad project, the most contaminated area of the southeastern part of the STS is two craters, Telkem-1 and Telkem-2, formed by nuclear explosions. These craters are contaminated with the fission products, cesium-137 and strontium-90, and with components of nuclear fuel, plutonium-239 and americium-241, and the activation product, europium-154. The considerable migration of radionuclides in the 40 years since the tests were conducted was not detected. The calculated effective dose for adults from radionuclides at the Telkem craters is approximately 7 mSv. In the northern part of the STS (Semirad 2 project) the most contaminated sites are located close to the area of radiological dispersion device tests. Annual effective doses from plutonium-239 and strontium-90 can reach over 8 mSv. There is no possibility to detect the dose, largely from micron-sized "hot particles" of high radioactivity spread across the STS territory. The STS is a unique scientific preserve where scientists from all over the world are welcome to conduct research. The Republic of Kazakhstan abandoned its nuclear arsenal and opened the path to the international community to a world free of nuclear weapons.

The chronologies and sediment accumulation rates for a lake sediment sequence from Lough Carra (Co. Mayo, western Ireland) were established by applying the constant initial concentration (CIC) and constant rate of supply (CRS) hypotheses to the measured 210Pbexcess profile. The resulting chronologies were validated using the artificial fallout radionuclides 137Cs and 241Am, which provide independent chronostratigraphic markers for the second half of the 20th century. The validity of extrapolating the derived CIC and CRS dates below the 210Pb dating horizon using average sedimentation rates was investigated using supplementary paleolimnological information and historical data. Our data confirm that such an extrapolation is well justified at sites characterised by relatively stable sedimentation conditions.

A nondestructive method based on low-energy, high-resolution photon spectrometry is presented which allows accurate determination of (239)Pu, (240)Pu, and (241)Am (as a daughter of (241)Pu) activities in radioactive particles containing relatively high levels of plutonium isotopes. The proposed method requires only one measurement for the establishment of an absolute efficiency curve. Since the density and composition of the radioactive particles of interest may vary, a self-absorption correction is required for the accurate determination of isotopic activities and ratios. This correction is carried out for each individual particle using the convenient gamma-ray emissions of (241)Am.

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a (137)Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data. The average biodiffusion coefficient, at 1.8 +/- 0.9 cm(2) y(-1), is in good agreement with the values quoted by other workers on the bioturbation effects of this polychaete species. The corresponding value for the biotransport coefficient was found to be 0.9 +/- 0.4 cm y(-1). The effects of non-local mixing were incorporated in a model to describe the temporal evolution of measured (99)Tc and (60)Co radionuclide sediment profiles in the eastern Irish Sea, influenced by radioactive waste discharged from the Sellafield reprocessing plant. Reworking conditions in the sediment column were simulated by considering an upper mixed layer, an exponentially decreasing diffusion coefficient, and appropriate biotransport coefficients to account for non-local mixing. The diffusion coefficients calculated from the (99)Tc and (60)Co cores were in the range 2-14 cm(2) y(-1), which are consistent with the values found by other workers in the same marine area, while the biotransport coefficients were similar to those obtained for a variety of macrobenthic organisms in controlled laboratories and field studies.

A stakeholder needs assessment, carried out under the EU-EURAC and EU-ENEN-II projects, clearly showed that, at the European level, there are a significant and constant need for post-graduates with skills in radiochemistry, radioecology, radiation dosimetry and environmental modelling and a smaller, but still important, demand for radiobiologists and bio-modellers. Most of these needs are from government organizations. If only the nuclear industry is considered, then the largest demand is for radio chemists and radiation protection dosimetry experts. Given this spectrum of need and existing capacity in the areas of radiobiology it was concluded that the needs identified would be most efficiently met by three new degree programs:European MSc Radiation Protection,European MSc Analytical Radiochemistry,European MSc Radioecology.All three master programs would be developed using the framework provided by the Bologna Convention and the lecturing could be shared among specialist Scientists within a network of collaborating universities. Therefore, educational plans have been developed for the above MSc degrees. These plans envisage each degree comprising three modules that are common to all the degrees (3 x 10 ECTS credits), three specialist modules (3 x 10 ECTS credits) and a research project (1 x 60 ECTS credits). The courses should be aimed, not only to fill the identified European post-graduate education gap in radiological sciences, but also to provide a modular structure that is easily accessed by stakeholders for CPD training. It is anticipated that the European Masters will meet the academic training requirements of qualified experts", as defined by the European Commission and the IAEA. At the Norwegian University of Life Sciences (UMB) a pilot MSc in Radioecology has successfully been initiated in collaboration with UK and France. (C) 2010 Elsevier B.V. All rights reserved.

The 129I content in precipitation, lake and river waters sampled in Ireland in 2005–2006 has been determined by accelerator mass spectrometry. In the case of lake and river waters, the data reveal little if any geographic dispersion with a mean (n=14) concentration of 4.6±1.2(1σ)×108 atoms L−1. In contrast, concentrations of 129I in precipitation show significant variations both in time and space, with concentrations ranging from a low of 1.9×108 atoms L−1 to a high of 303×108 atoms L−1. These variations in precipitation are attributed to temporal changes in on-going discharges of 129I from west European reprocessing plants in conjunction with the trajectories of airstreams prevailing over Ireland at the time of sampling.

New data are reported on the concentrations, isotopic composition and speciation of americium, plutonium and uranium in surface and ground waters in the Sarzhal region of the Semipalatinsk Test Site, and an adjacent area including the settlement of Sarzhal. The data relate to filtered water and suspended particulate from (a) streams originating in the Degelen Mountains, (b) the Tel′kem 1 and Tel′kem 2 atomic craters, and (c) wells on farms located within the study area and at Sarzhal. The measurements show that 241Am, 239,240Pu and 238U concentrations in well waters within the study area are in the range 0.04–87 mBq dm−3, 0.7–99 mBq dm−3, and 74–213 mBq dm−3, respectively, and for 241Am and 239,240Pu are elevated above the levels expected solely on the basis of global fallout. Concentrations in streams sourced in the Degelen Mountains are similar, while concentrations in the two water-filled atomic craters are somewhat higher. Suspended particulate concentrations in well waters vary considerably, though median values are very low, at 0.01 mBq dm−3, 0.08 mBq dm−3 and 0.32 mBq dm−3 for 241Am, 239,240Pu and 238U, respectively. The 235U/238U isotopic ratio in almost all well and stream waters is slightly elevated above the 'best estimate' value for natural uranium worldwide, suggesting that some of the uranium in these waters is of test-site provenance. Redox analysis shows that on average most of the plutonium present in the microfiltered fraction of these waters is in a chemically reduced form (mean 69%; 95% confidence interval 53–85%). In the case of the atomic craters, the proportion is even higher. As expected, all of the americium present appears to be in a reduced form. Calculations suggest that annual committed effective doses to individual adults arising from the daily ingestion of these well waters are in the range 11–42 μSv (mean 21 μSv). Presently, the ground water feeding these wells would not appear to be contaminated with radioactivity from past underground testing in the Degelen Mountains or from the Tel′kem explosions.

In-vitro leaching of radioactive 'hot' particles isolated from soils sampled at the Semipalatinsk Nuclear Test Site has been carried out in order to evaluate the fraction of plutonium activity released into simulated human stomach and small intestine fluids during digestion. Characterisation of the particles (10-100 Bq(239,240)Pu) and investigation of their dissolution kinetics in simulated fluids has been accomplished using a combination of high-resolution alpha-spectrometry, gamma-spectrometry and liquid scintillation counting. The results of these analyses indicate that plutonium transfer across the human gut following the ingestion of 'hot' particles can be up to two orders of magnitude lower than that expected for plutonium in a more soluble form, and show that for areas affected by local fallout, use of published ingestion dose coefficients, together with bulk radionuclide concentrations in soil, may lead to a considerable overestimation of systemic uptake via the ingestion pathway.

Recent studies have shown that accumulation of 99Tc in seabed sediments labelled by authorised radioactive liquid discharges into the NE Irish Sea from the Sellafield reprocessing complex is greater than previously thought. In this paper, new data on 99Tc concentration profiles in subtidal and intertidal sediments from the eastern and western Irish Sea are provided with a view to elucidating the processes responsible for the incorporation and retention of 99Tc in the seabed. The data show that substantial amounts of 99Tc have accumulated in the fine-grained subtidal sediments off the Cumbrian coast, particularly after increased releases from Sellafield following the commissioning of the Enhanced Actinide Removal Plant (EARP) in 1994. In all the cores taken in this area, 99Tc has been found to be present to depths in excess of 30cm. Analysis of 137Cs and 241Am profiles, together with other supporting geochemical data, show a high degree of homogenisation of the sediments down to these depths as a result of physical and biological processes, and confirm that incorporation of 99Tc into the sediment compartment is actually the result of mixing and reworking, rather than active sediment accumulation. In contrast, active deposition of material transported from this mixed pool of sediment appears to be the dominant mechanism controlling 99Tc profiles in intertidal areas close to the Sellafield discharge outfall.Data obtained from the analysis of subtidal sediment cores from the western Irish Sea mud basin suggest that similar mixing processes to those occurring in the subtidal sediments of the eastern Irish Sea are also active in this area. Time-series data on 99Tc concentrations in surficial sediments from this basin, gathered in the period 1988–2004, inclusive, show a clear increase in concentrations, by a factor of ∼2, between samples collected pre-EARP and post-EARP. The constancy of 99Tc concentrations in surface sediments throughout the 1980s and the early-1990s suggests that little redissolution and export of 99Tc occurred over this extended period. A similar observation applies to the post-EARP period, when concentrations remained relatively constant despite the reported steady decrease in 99Tc concentrations in the overlying waters.This apparent lack of remobilisation is consistent with data from sequential extraction analyses, which indicate that the bulk of the 99Tc is strongly bound to non-labile geochemical phases, with only a small proportion associated with exchangeable and acido-soluble phases. Further, these analyses show that 99Tc is not associated with oxygen-sensitive and highly-reactive acid-volatile sulphides (AVS) to any significant extent.

The solid speciation of some radiologically important radioelements has been examined in soils sampled at the former Semipalatinsk (Nuclear) Test Site (STS) and at Kurdai, the site of a former major uranium mining operation − both situated in Kazakhstan. Specifically, the partitioning of radiostrontium, radiocaesium and plutonium has been examined using sequential extraction on selected soils from the test site, while the partitioning of radium and uranium has been evaluated in soils at Kurdai. The data show that at the STS, in general, little (if any) of the radiostrontium, radiocaesium and plutonium is in an exchangeable form, withthe great bulk of the radiostrontium and radiocaesium in a strongly bound or refractory form. In the case of plutonium, the proportion in a strongly bound or refractory form varies from 40% to 95% depending on site and appears to be a function of the explosive yield involved. At the Kurdai ore deposit, less than 5% of the uranium and radium is in an exchangeable form, with some 35-60% of the uranium and the bulk of the radium in a strongly bound or residual form.

Proton- and neutron-induced activation products in the components of a high-pressure [(18)O]H(2)O target vessel used for the production of (18)F(-) in a medical cyclotron have been identified using high resolution gamma spectrometry. The activities leached from the target vessel into the [(18)O]H(2)O during irradiation, and the distribution of the identified radionuclide impurities in the various cartridges and solutions used in the [(18)F]FDG synthesis process have been measured and are discussed from the perspective of waste disposal. The results indicate that, at the energies and beam currents employed, only a few, relatively short-lived radionuclides are present in the irradiated [(18)O]H(2)O, and that the activities involved (<10 kBq in each case) are well below typical exemption limits. Activities of beta-emitting (3)H in irradiated [(18)O]H(2)O, produced via the (18)O(p,(3)H)(16)O reaction, have also been determined using liquid scintillation spectrometry. Measured activity concentrations, in the range 150-180 kBq g(-1), are consistent with those reported by other workers. Analyses of the synthesised [(18)F]FDG confirm the radiochemical purity of the product, both for (3)H and for gamma-emitting radionuclides in the energy range 25-1650 keV.

The database on tritium concentrations in streams, atomic lakes, ground waters and well waters at the Semipalatinsk Nuclear Test Site (STS) is by no means extensive, given the scale of nuclear testing undertaken at the site in the past. Here, we highlight the extent of the present database by summarising all of the readily accessible (published) data on tritium levels in the various waters of interest. In addition, we present new data on tritium gathered in the course of fieldwork in 2004 and 2005, by participants in the SEMIRAD 2 Project. We also review the status of present knowledge in regard to the mobility of tritium within and off the STS, by focussing on specific case studies, and offer suggestions as to the shape future research endeavours might take that, in our opinion, would be most cost effective.

1 Institut de Radioprotection et de Sûreté Nucléaire, BP3 Cadarache 13108 Saint-Paul-lez Durance, France 2 School of Physics, University College Dublin, Belf i ld, Dublin 4, Ireland 3 Department of Inorganic Chemistry, Al-Farabi Kazak h National University, Almaty, Kazakhstan 4 Institute of Radiation Safety and Ecology, Nationa l Nuclear Center of Kazakhstan, Kazakhstan 5 AECL Chalk River Laboratory, Plant Road, Chalk River, Ontario K0J 1P0, Canada

Analysis of strontium-90 in soils showed that most of the SEMIRAD1 and SEMIRAD2 project areas were little contaminated with this radionuclide indicating that the extensive testing of nuclear devices at the STS (including more than 100 groundlevel, aerial and crater-producing explosions) resulted in little dispersed local contamination by fission products, including strontium-90. However, local strontium-90 contamination produced by the Telkem, crater-producing explosions within the SEMIRAD1 study area was evident at distances less that about 3 km from the explosion sites. Within the craters soil strontium-90 concentrations reached 1 kBq kg–1. Around the craters strontium-90 was more widely dispersed than fuel-associated radionuclides and evidence exists to suggest that it is much more mobile within the environment. Within the SEMIRAD1 study area strontium-90 levels were also elevated below the path of the fallout plume produced by the testing of the Soviet Union’s first H-bomb in 1953. Radiation doses to residents of the SEMIRAD1 study area were calculated using a modified ECOSYS model. These indicated that strontium-90 was a major contributor to dose in the more contaminated regions around Telkem and close to the village of Sarzhal. Annual doses to adult males living close to Telkem were assessed to currently be about 7 mSv, but these were predicted to fall in line with the physical half-life (28.64 years) of strontium- 90. Localised hotspots that are significantly contaminated with strontium-90 are to be found within Technical Area 4a, which straddles the southern boundary of the SEMIRAD2 study area. About 35 areas of contamination produced by the testing of radiation dispersion devices have been identified. They are considered hazardous since they are unmarked and have been grazed by animals from local farms. They may also present a terrorism hazard. Calculations made using the ICRP biokinetic model for strontium suggest that, under conditions of chronic ingestion, radiation doses to farmers and their families could reach about 4 mSvy–1.

Spatial and temporal trends in 129I and 99Tc concentrations around the Irish coastline have been evaluated using Fucus vesiculosus as a bio-indicator. 129I concentrations in a recent set of seawater samples have also been recorded and reveal an identical spatial pattern. Concentrations of 129I in Fucus from the northeast coast of Ireland proved to be at least two orders of magnitude higher than concentrations in Fucus from the west coast. The 129I content of Fucus increased significantly between 1985 and 2003, in line with increases in discharges of 129I from the Sellafield nuclear reprocessing plant. Similar trends were observed in the case of 99Tc. 129I/99Tc ratios in Irish seawater were deduced from the Fucus data, and compared to ratios in discharges from Sellafield and from the French reprocessing plant at Cap de la Hague. Levels of 129I and 99Tc in Fucus from the west coast were found to be enhanced with respect to levels in seaweeds from other regions in the Northern Hemisphere unaffected by discharges from nuclear installations such as those referred to.

Sequential extraction has been used extensively to study the solid partitioning of radionuclides in soils and sediments. A difficulty with sequential extraction is that radionuclides released by a particular extractant can be resorbed and artificially redistributed amongst the remaining solid phases. Here, we describe experiments (on selected model phase and natural materials), which were designed to determine whether the inclusion of a chelating agent (sodium citrate) in an established sequential extraction protocol (a) inhibits post-extraction resorption of plutonium, (b) increases non-targeted dissolution of sediment phases, and (c) gives rise to unwanted ligand competition for plutonium. The results clearly demonstrate the capacity of citrate to inhibit the resorption of plutonium from the various extractants, and confirm that there is no discernible increase in non-targeted phase dissolution, but indicate significant ligand competition with the carbonate phase. The merits of using citrate are discussed and an optimised sequential extraction protocol that includes citrate is proposed. Finally, the protocol is applied to oxic and anoxic sediments sampled in the NE Irish Sea and the Roads of Cherbourg, and it is shown that the bulk of the plutonium on these sediments is associated with the more labile geochemical fractions.