On-site radioactive soil contamination at the Andreeva Bay shore technical base, Northwest Russia

The radioactive waste (RAW) storage site at Andreeva Bay in the Russian Northwest has experienced radioactive contamination both as a result of activities carried out at the site and due to incidents that have occurred there in the past such as accidental releases of radioactive materials. The site is an interesting case study for decommissioning due to the extremely large amounts of radioactivity present at the site and the conditions under which it is stored; very little has been previously published in the scientific literature about this site. This paper complements the paper describing dose rates at Andreeva Bay which is published in this issue of Journal of Environmental Radioactivity by the same authors. This study presents new data related to the activity concentrations of (137)Cs and (90)Sr in surface soils and measurements of alpha- and beta-particle fluxes taken at different areas around the site. Limited data on 60Co is also presented. The results of the study indicate that the main areas of site contamination are associated with the former spent nuclear fuel storage facility at Building 5, due to accidental discharges which began in 1982. Substantial contamination is also observed at the solid radioactive waste storage facilities, probably due to the ingress of water into these facilities. More than 240 samples were measured: maximum contamination levels were 1 x 10(6)Bq/kg (137)Cs (mean value 4.1 x 10(5)Bq/kg) and 4 x 10(6)Bq/kg (90)Sr (mean value 1.2 x1 0(5)Bq/kg). Localised patches of alpha and beta contamination were also observed throughout the site.     

Intraspecific variation in Melandrium album along a radioactive contamination gradient at the Eastern Ural radioactive trace

Specific ecogenetic features of plants and parameters of seed progeny have been studied in Melandrium album cenopopulations from test plots established along the radioactive contamination gradient in the zone of the Eastern Ural Radioactive Trace (EURT), where absorbed radiation doses in buffer and impact plots exceeded the background level by factors of 2–18 and 330–418, respectively. It has been shown that interannual variation in parameters characterizing the viability of seed progeny largely depends on fluctuations of weather conditions. This dependence is more distinct in cenopopulations from the EURT than in control samples, which is indicative of interaction between radiation and other relevant ecological factors. The radioresistance of seed progeny is contingent on its viability, being independent of radiation load at the sites of maternal plant growth. Hermaphrodite plants occur only in irradiated M. album cenopopulations. This character is inherited: all F ₁ descendants of such plants grown in a vegetation experiment had hermaphrodite flowers. The mutability of seed progeny formed in the EURT zone exceeds the background level. The occurrence and frequencies of recorded anomalies has proved to vary by years and, therefore, can be interpreted as nonheritable modifications.     

Radioactive contamination in the Arctic--sources, dose assessment and potential risks

Arctic residents, whose diets comprise a large proportion of traditional terrestrial and freshwater foodstuffs, have received the highest radiation exposures to artificial radionuclides in the Arctic. Doses to members of both the average population and selected indigenous population groups in the Arctic depend on the rates of consumption of locally-derived terrestrial and freshwater foodstuffs, including reindeer/caribou meat, freshwater fish, goat cheese, berries, mushrooms and lamb. The vulnerability of arctic populations, especially indigenous peoples, to radiocaesium deposition is much greater than for temperate populations due to the importance of terrestrial, semi-natural exposure pathways where there is high radiocaesium transfer and a long ecological half-life for this radionuclide. In contrast, arctic residents with diets largely comprising marine foodstuffs have received comparatively low radiation exposures because of the lower levels of contamination of marine organisms. Using arctic-specific information, the predicted collective dose is five times higher than that estimated by UNSCEAR for temperate areas. The greatest threats to human health and the environment posed by human and industrial activities in the Arctic are associated with the potential for accidents in the civilian and military nuclear sectors. Of most concern are the consequences of potential accidents in nuclear power plant reactors, during the handling and storage of nuclear weapons, in the decommissioning of nuclear submarines and in the disposal of spent nuclear fuel from vessels. It is important to foster a close association between risk assessment and practical programmes for the purposes of improving monitoring, formulating response strategies and implementing action plans.     

Genetic consequences of radioactive contamination by the Chernobyl fallout to agricultural crops

The genetic consequences of radioactive contamination by the fallout to agricultural crops after the accident at the Chernobyl NPP in 1986 have been studied. In the first, acute, period of this accident, when the absorbed dose was primarily due to external beta- and gamma-irradiation, the radiation injury of agricultural crops, according to the basic cytogenetic tests, resembled the effect produced by acute gamma-irradiation at comparable doses. The yield of cytogenetic damage in leaf meristem of plants grown in the 10-km zone of the ChNPP in 1987-1989 (the period of chronic, lower level radiation exposure) was shown to be enhanced and dependent on the level of radioactive contamination. The rate of decline with time in cytogenetic damage induced by chronic exposure lagged considerably behind that of the radiation exposure. Analysis of genetic variability in three sequential generations of rye and wheat revealed increased cytogenetic damage in plants exposed to chronic irradiation during the 2nd and 3rd years.     

Use of AMS in the marine environment

In recent years, the field of AMS has expanded into many areas of science. This paper reviews a variety of applications of AMS in the marine environment, focusing particularly on recent developments and applications. Following a brief summary of the three main isotope techniques used in environmental studies: dating, tracing and source identification, a number of applications are considered. Traditional (14)C-dating is no longer the dominant application of AMS measurements, and together with measurements of (10)Be, (26)Al and (36)Cl, much of the research is now directed towards an understanding of global climate change via studies of oceanic circulation, atmospheric processes and past climates by cosmic ray exposure dating. Profiles of long-lived cosmogenic radionuclides in sediments and ice cores, as a function of depth and, thus, age, provide key information on past solar variability, production rate changes and atmospheric transport and deposition mechanisms. Useful paleoclimatic information may be derived from these archives both because deposition is influenced by climate and because solar activity (which influences production) and solar radiance (which influences climate) are correlated. In recent years, emphasis has been put on the development and application of AMS techniques for the measurement of heavier long-lived isotopes, including (99)Tc, (129)I, (236)U and other actinide isotopes. AMS combines ultra low detection limits and the possibility to analyse isotope ratios that can be difficult with traditional instruments and has been used in a number of applications on the consequences and uses of releases from nuclear energy. Finally, the use AMS in environmental sciences is expected to expand further in the foreseeable future with long-lived cosmogenic radionuclides contributing to a large body of knowledge on processes involving atmosphere, oceans, ice sheets, biosphere, soils and sediments.     

Mesoscale modelling of radioactive contamination formation in Ukraine caused by the Chernobyl accident

This work is devoted to the reconstruction of time-dependent radioactive contamination fields in the territory of Ukraine in the initial period of the Chernobyl accident using the model of atmospheric transport LEDI (Lagrangian-Eulerian DIffusion model). The modelling results were compared with available 137Cs air and ground contamination measurement data. The 137Cs atmospheric transport over the territory of Ukraine was simulated during the first 12 days after the accident (from 26 April to 7 May 1986) using real aerological information and rain measurement network data. The detailed scenario of the release from the accidental unit of the Chernobyl nuclear plant has been built (including time-dependent radioactivity release intensity and time-varied height of the release). The calculations have enabled to explain the main features of spatial and temporal variations of radioactive contamination fields over the territory of Ukraine on the regional scale, including the formation of the major large-scale spots of radioactive contamination caused by dry and wet deposition.     

On radiocarbon and plutonium leakage to groundwater in the vicinity of a shallow-land radioactive waste repository

A shallow-land radioactive waste repository operated in boggy forest environment from 1963 to 1989. During the operation period, a considerable amount of technogenic radionuclides, in solidified state, was disposed into the vault established in the geological structure at the depth of up to 3 m. Environmental monitoring activities started after the closure of the repository in 1989. Recent investigations revealed transfer of radiocarbon and plutonium to the groundwater in the prevailing flow direction. Activity concentration of ^239,240Pu in non-filtered fraction of the groundwater from observation well no. 4 determined by alpha-spectrometry was 6.4 × 10⁻⁵ Bq l⁻¹ in 2005, and 3.2 × 10⁻⁴ Bq l⁻¹ in 2006. Further analysis of colloid-facilitated transport of plutonium is planned. Variation of ¹⁴C activity concentration in the same well was monitored in 2006. It varied from 0.2 ± 0.1 Bq l⁻¹ in October to 2.8 ± 0.6 Bq l⁻¹ in June and July. Results imply further research into radiocarbon transfer to atmosphere and selected plant species.     

A new approach to assessment and management of the impact from medical liquid radioactive waste

The Swedish regulations concerning disposal of clinical radioactive waste are currently under revision and a graded approach is proposed for risk limitation purposes. To assist the revision procedures, a screening study was performed to estimate public exposures from liquid releases from hospitals to public sewers. The results showed that doses to sewage workers were above the dose constraint of 100muSva(-1) especially for (131)I and (99m)Tc. Hence, a dynamic model, LUCIA, was developed for realistic assessments in which radionuclide transportation in sewers was modelled. Probabilistic simulations were performed to obtain probability distributions of radionuclide concentrations in sludge. Concurrently, estimates of the effective doses to sewage workers decreased significantly and were below 10muSva(-1) except for (111)In and (131)I. However, the Kd-coefficients representing the partition of radioactivity between water and sludge in sewers are highly uncertain for (111)In. As shown by sensitivity studies, these values are the major determinant of the exposures in sewers.     

Tritium concentrations in the atmospheric environment at Rokkasho, Japan before the final testing of the spent nuclear fuel reprocessing plant

This study aimed at obtaining background tritium concentrations in precipitation and air at Rokkasho where the first commercial spent nuclear fuel reprocessing plant in Japan has been under construction. Tritium concentration in monthly precipitation during fiscal years 2001-2005 had a seasonal variation pattern which was high in spring and low in summer. The tritium concentration was higher than that observed at Chiba City as a whole. The seasonal peak concentration at Rokkasho was generally higher than that at Chiba City, while the baseline concentrations of both were similar. The reason for the difference may be the effect of air mass from the Asian continent which is considered to have high tritium concentration. Atmospheric tritium was operationally separated into HTO, HT and hydrocarbon (CH₃T) fractions, and the samples collected every 3 d-14 d during fiscal year 2005 were analyzed for these fractions. The HTO concentration as radioactivity in water correlated well with that in the precipitation samples. The HT concentration was the highest among the chemical forms analyzed, followed by the HTO and CH₃T concentrations. The HT and CH₃T concentrations did not have clear seasonal variation patterns. The HT concentration followed the decline previously reported by Mason and Östlund with an apparent half-life of 4.8 y. The apparent and environmental half-lives of CH₃T were estimated as 9.2 y and 36.5 y, respectively, by combining the present data with literature data. The Intergovernmental Panel on Climate Change used the atmospheric lifetime of 12 y for CH₄ to estimate global warming in its 2007 report. The longer environmental half-life of CH₃T suggested its supply from other sources than past nuclear weapon testing in the atmosphere.     

Customisation of the decision support system MOIRA-PLUS for applications to the marine environment

The present short communication describes a technique to customise the decision system MOIRA-PLUS for applications to the marine environment. MOIRA-PLUS was originally designed to predict the behaviour of ¹³⁷Cs and ⁹⁰Sr in fresh water ecosystems and to evaluate the environmental, social and economic impacts of selected countermeasures aimed at restoring the polluted environment and at reducing the doses to man. An example of application for predicting the concentration of radiocaesium of Chernobyl origin in the Mediterranean Sea is described and discussed. The technique allows the user to easily integrate existing state-of-the-art box models of sea water circulation into the MOIRA-PLUS decision system.     

Movement of a tritium plume in shallow groundwater at a legacy low-level radioactive waste disposal site in eastern Australia

Between 1960 and 1968 low-level radioactive waste was buried in a series of shallow trenches near the Lucas Heights facility, south of Sydney, Australia. Groundwater monitoring carried out since the mid 1970s indicates that with the exception of tritium, no radioactivity above typical background levels has been detected outside the immediate vicinity of the trenches. The maximum tritium level detected in groundwater was 390 kBq/L and the median value was 5400 Bq/L, decay corrected to the time of disposal. Since 1968, a plume of tritiated water has migrated from the disposal trenches and extends at least 100 m from the source area. Tritium in rainfall is negligible, however leachate from an adjacent landfill represents a significant additional tritium source. Study data indicate variation in concentration levels and plume distribution in response to wet and dry climatic periods and have been used to determine pathways for tritium migration through the subsurface.     

Bioindication of the anthropogenic effects on micropopulations of Pinus sylvestris,L. in the vicinity of a plant for the storage and processing of radioactive waste and in the Chernobyl NPP zone

Results of a comparative analysis of the frequency and spectrum of cytogenetic anomalies are presented for reproductive (seeds) and vegetative (needles) samples taken from Scotch pine (Pinus sylvestris, L.) micropopulations growing at sites with differing levels of radioactive contamination in the Chernobyl NPP 30 km zone, and at the location of a facility for the processing and storage of radioactive wastes (the 'Radon' LWPE, near the town of Sosnovy Bor in the Leningrad Region). The data obtained indicate the presence of genotoxic contaminants in the environment of the tree micropopulations. Chemical toxins make the main contribution to the environmental contamination in the Sosnovy Bor area as compared with the influence of ionising radiation in the Chernobyl 30 km zone. The higher radioresistance of seeds of Scotch pine growing on the area of the 'Radon' LWPE and in the centre of Sosnovy Bor town was revealed with acute gamma-radiation.     

Hazardous waste, impact on health and environment for development of better waste management strategies in future in India

Industry has become an essential part of modern society, and waste production is an inevitable outcome of the developmental activities. A material becomes waste when it is discarded without expecting to be compensated for its inherent value. These wastes may pose a potential hazard to the human health or the environment (soil, air, water) when improperly treated, stored, transported or disposed off or managed. Currently in India even though hazardous wastes, emanations and effluents are regulated, solid wastes often are disposed off indiscriminately posing health and environmental risk. In view of this, management of hazardous wastes including their disposal in environment friendly and economically viable way is very important and therefore suggestions are made for developing better strategies. Out of the various categories of the wastes, solid waste contributes a major share towards environmental degradation. The present paper outlines the nature of the wastes, waste generating industries, waste characterization, health and environmental implications of wastes management practices, steps towards planning, design and development of models for effective hazardous waste management, treatment, approaches and regulations for disposal of hazardous waste. Appraisal of the whole situation with reference to Indian scenario is attempted so that a better cost-effective strategies for waste management be evolved in future.     

Intrapopulation variation in the quality of dandelion seed progeny in zones of chemical and radioactive contamination

Interfamilial variation in metal tolerance and radioresistance of seed progeny from F ₁ plants was studied in the dandelion from cenopopulations growing over several decades in gradients of radioactive or chemical contamination. The progeny from the impact zone of the Eastern Ural Radioactive Trace (EURT) proved to be highly viable but had latent injuries that accounted for a high sensitivity to additional technogenic impact. In the F ₁ generation from the zone of chemical contamination, high seed viability was combined with increased tolerance to additional impact of radiation and heavy metals. No significant differences between responses to challenge with habitual and new factors were revealed in samples from either zone.     

Lead contamination and isotope signatures in the urban environment of Hong Kong

The source and the extent of Pb pollution in the urban environment of Hong Kong were investigated at five different urban settings selected on the basis of their annual average daily traffic (AADT) varying from less than 100 to 61,700. In addition, a small distant island without any traffic was selected to establish the possible baseline values. The surface environmental samples studied consisted of street and tunnel dusts, gully sediments, and a limited number of roadside topsoils. The analytical results clearly indicated variable degrees of Pb contamination in these urban settings. However, the level of contamination varied significantly among different types of samples collected at the same location. Pb concentrations of roadside topsoils (79+/-22 micrograms/g) and gully sediments (278+/-88 micrograms/g) were lower than those of the corresponding road dusts (327+/-54 micrograms/g). The Pb isotope compositions in different urban settings varied considerably. The bedrock in the small island had the lowest Pb concentration (12 micrograms/g) but with the highest 206Pb/207Pb ratio (1.2206), whereas the tunnel ceiling dusts with the highest level of Pb (1410 micrograms/g) had the lowest 206Pb/207Pb ratio (1.1062). Despite the significant differences in vehicle types and traffic volumes, and the presence of several different petroleum retailers in Hong Kong, the Pb isotope ratios of road dusts (206Pb/207Pb: 1.1553+/-0.0043, 208Pb/207Pb: 2.4408+/-0.0084) varied within a relatively narrow range among all the five urban sampling sites. On the other hand, the Pb isotopic compositions of gully sediments (206Pb/207Pb: 1.1515+/-0.0145, 208Pb/207Pb: 2.4322+/-0.0198) varied noticeably within the same setting, but were reasonably comparable across the different study sites. In general, the 206Pb/207Pb ratios of road dusts can be used to estimate the direct contribution from automobile emissions, whereas those of gully sediments might reflect the effects of the mixing of different anthropogenic sources. The Pb isotope signatures in the urban environment of Hong Kong clearly suggested that anthropogenic Pb in the environment originated from Pb ore with a low 206Pb/207Pb ratio (such as the Australian Pb ore and similar sources in Southeast Asia) were significantly different from those of the anthropogenic Pb present in the neighboring Pearl River Delta (PRD) region.     

Dose assessment for marine biota and humans from discharge of (131)I to the marine environment and uptake by algae in Sydney, Australia

Iodine-131 reaches the marine environment through its excretion to the sewer by nuclear medicine patients followed by discharge through coastal and deepwater outfalls. ¹³¹I has been detected in macroalgae, which bio-accumulate iodine, growing near the coastal outfall of Cronulla sewage treatment plant (STP) since 1995. During this study, ¹³¹I levels in liquid effluent and sludge from three Sydney STPs as well as in macroalgae (Ulva sp. and Ecklonia radiata) growing near their shoreline outfalls were measured. Concentration factors of 176 for Ulva sp. and 526 for E. radiata were derived. Radiation dose rates to marine biota from ¹³¹I discharged to coastal waters calculated using the ERICA dose assessment tool were below the ERICA screening level of 10 μGy/hr. Radiation dose rates to humans from immersion in seawater or consumption of Ulva sp. containing ¹³¹I were three and two orders of magnitude below the IAEA screening level of 10 μSv/year, respectively.