Justin P. Gwynn

210Po, 210Pb, 40K and 137Cs in edible wild berries and mushrooms and ingestion doses to man from high consumption rates of these wild foods.

This paper discusses activity concentrations of (210)Po, (210)Pb, (40)K and (137)Cs in edible wild berries and mushrooms collected from Øvre Dividalen national park, Northern Norway and derives committed effective ingestion doses to man based on high consumption rates of these wild foods. Edible wild berries and mushrooms accumulated similar levels of (210)Pb, but mushrooms accumulated higher levels of (210)Po and (40)K than berries. There appears to be a clear difference in the ability of Leccinum spp. of fungi to accumulate (210)Po and/or translocate (210)Po to mushrooms compared to Russula spp. of fungi. Activity concentrations of (137)Cs in edible wild berries and mushrooms from Øvre Dividalen national park reflected the lower levels of fallout of this radionuclide in Northern Norway compared to more central areas following the Chernobyl accident. For mushrooms, ingestion doses are dominated by (210)Po, while for berries, (40)K is typically the main contributor to dose. Based on high consumption rates, ingestion doses arising from the combination of (210)Po, (210)Pb and (40)K were up to 0.05 mSv/a for berries and 0.50 mSv/a for mushrooms. Consumption of such wild foods may result in a significant contribution to total annual doses when consumed in large quantities, particularly when selecting mushrooms species that accumulate high activity concentrations of (210)Po.

Environmental impact assessment of radionuclide and metal contamination at the former U site at Kadji Sai, Kyrgyzstan

During 1949-1967, a U mine, a coal-fired thermal power plant and a processing plant for the extraction of U from the produced ash were operated at the Kadji Sai U mining site in Tonsk district, Issyk-Kul County, Kyrgyzstan. The Kadji Sai U legacy site represents a source of contamination of the local environment by naturally occurring radionuclides and associated trace elements. To assess the environmental impact of radionuclides and trace metals at the site, field expeditions were performed in 2007 and 2008 by the Joint collaboration between Norway, Kazakhstan, Kyrgyzstan, Tajikistan (JNKKT) project and the NATO SfP RESCA project. In addition to in situ gamma and Rn dose rate measurements, sampling included at site fractionation of water and sampling of water, fish, sediment, soils and vegetation. The concentrations of radionuclides and trace metals in water from Issyk-Kul Lake were in general low, but surprisingly high for As. Uptake of U and As was also observed in fish from the lake with maximum bioconcentration factors for liver of 1.6 and 75, respectively. The concentrations of U in water within the Kadji Sai area varied from 0.01 to 0.05 mg/L, except for downstream from the mining area where U reached a factor of 10 higher, 0.2 mg/L. Uranium concentrations in the drinking water of Kadji Sai village were about the level recommended by the WHO for drinking water. The (234)U/(238)U activity ratio reflected equilibrium conditions in the mining pond, but far from equilibrium outside this area (reaching 2.3 for an artesian well). Uranium, As and Ni were mainly present as low molecular mass (LMM, less than 10 kDa) species in all samples, indicating that these elemental species are mobile and potentially bioavailable. The soils from the mining sites were enriched in U, As and trace metals. Hot spots with elevated radioactivity levels were easily detected in Kadji Sai and radioactive particles were observed. The presence of particles carrying significant amount of radioactivity and toxic trace elements may represent a hazard during strong wind events (wind erosion). Based on sequential extractions, most of the elements were strongly associated with mineral matter, except for U and As having a relatively high remobilization potential. Low Kd was obtained for U (3.5 × 10(2) L/kg d.w.), intermediate Kds (~3 × 10(3) L/kg d.w.) were obtained for (226)Ra, As and Ni, while a high Kd (2.2 × 10(5) L/kg d.w.) were obtained for Pb. The accumulation of metals in fish gills reflected the LMM species in the Issyk-Kul water, and did not show any bioaccumulation. The muscle Hg concentrations in all fish species were low and did not represent any health risk even for groups at risk. Total gamma and Rn dose rate to man amounted to about 12 mSv/y, while the highest calculated dose rate for non-human species based on the ERICA Assessment Tool were obtained in terrestrial plants (164 μGy/h) due to the Ra exposure. The results obtained showed that radiation doses to resident public at all of the investigated sites in the Kadji Sai area were in general relatively low. Low radiological risk and no detrimental health impact on resident public can be expected at these sites. However, exposure to Rn and Tn in the living environment can be further reduced by implementing simple countermeasures such as ventilation of dwelling cellars. More focus in the Kadji Sai area should probably be put on trace elements, especially the As uptake in fish in Lake Issyk-Kul.

Assessment of Elevated Radionuclide Levels in Soils Associated with an Avian Colony in a High Arctic Environment

This article presents the results of an investigation into the occurrence of elevated levels of radionuclides in soils associated with a seabird colony in the Arctic. Soils and other materials were collected from a seabird colony (primarily composed of kittiwakes) in Kongsfjorden, located in the High Arctic archipelago of Svalbard. The samples were analyzed for a suite of gamma emitting natural and anthropogenic radionuclides, including 137Cs and nuclides of the 238U and 232Th series, to establish the level of enrichment and the behavior of the radionuclides in the immediate area. The results indicate that soils near the colony exhibit enrichment factors of 8 for 137Cs, 5 for 238U and 2 for 226Ra compared to the nuclide content of soils from the general area. The spatial patterns of the nuclides in the soil are consistent with enrichment of the soil via run-off draining from a large accumulation of fecal and nesting material that has developed at the base of the colony. 137Cs ingress to the soil appears to have peaked at some point in the past as patterns of enrichment at the colony are different to those exhibited by 238U, which must be assumed to be a steady state contribution. The means of introduction of radionuclides to the colony remains unclear but the transfer of 137Cs from the marine environment to the terrestrial environment via the food chain and deposition of feces is discussed.

Radiological status of the marine environment in the Barents Sea.

This paper presents the results of Norwegian radiological monitoring of the Barents Sea in 2007, 2008 and 2009. Activity concentrations of the anthropogenic radionuclides (137)Cs, (90)Sr, (239,240)Pu and (241)Am in seawater were low and up to an order of magnitude lower than in previous decades. Activity concentrations of (99)Tc in seawater were low but remain elevated compared to levels prior to the increased discharge of this radionuclide from Sellafield in the 1990s. Activity concentrations of the naturally occurring radionuclide (226)Ra in seawater were comparable to expected background values. Activity concentrations of (137)Cs in surface sediments were low, with higher values observed in sediments from coastal areas along the Norwegian mainland than from locations in the open sea. Activity concentrations of (137)Cs and (99)Tc in marine biota were low and up to an order of magnitude lower than in previous decades. Committed effective dose rates to man from anthropogenic radionuclides via the consumption of seafood from the Barents Sea were low and are not a cause for concern. Weighted absorbed dose rates to biota from anthropogenic radionuclides were low and orders of magnitude below a predicted no effect screening level of 10 μGy/h. Dose rates to man from consumption of seafood and dose rates to biota in the marine environment are dominated by the contribution from naturally occurring radionuclides.

Main results of the 2012 joint Norwegian–Russian expedition to the dumping sites of the nuclear submarine K-27 and solid radioactive waste in Stepovogo Fjord, Novaya Zemlya

This paper reports the main results of the 2012 joint Norwegian-Russian expedition to investigate the radioecological situation of the Stepovogo Fjord on the eastern coast of Novaya Zemlya, where the nuclear submarine K-27 and solid radioactive waste was dumped. Based on in situ gamma measurements and the analysis of seawater and sediment samples taken around the submarine, there was no indication of any leakage from the reactor units of K-27. With regard to the radioecological status of Stepovogo Fjord, activity concentrations of all radionuclides in seawater, sediment and biota in 2012 were in general lower than reported from the previous investigations in the 1990s. However in 2012, the activity concentrations of (137)Cs and, to a lesser extent, those of (90)Sr remained elevated in bottom water from the inner part of Stepovogo Fjord compared with surface water and the outer part of Stepovogo Fjord. Deviations from expected (238)Pu/(239,240)Pu activity ratios and (240)Pu/(239)Pu atom ratios in some sediment samples from the inner part of Stepovogo Fjord observed in this study and earlier studies may indicate the possibility of leakages from dumped waste from different nuclear sources. Although the current environmental levels of radionuclides in Stepovogo Fjord are not of immediate cause for concern, further monitoring of the situation is warranted.

Radioecology of terrestrial arctic ecosystems

Publisher Summary This chapter discusses the radioecology of terrestrial Arctic ecosystems. The status of radioactive contamination within the Arctic region remains at focus. Although contamination levels in the terrestrial environment remain quite low, the special status of the region necessitates ongoing monitoring and research to elucidate fully the impacts of current levels of radionuclides on the environment and how future contamination might affect the ecosystem and its inhabitants. The presence of potential sources of future nuclear contamination in locations that can impact the Arctic places further emphasis on the necessity to be able to predict the behavior and radioecology of contaminants within the Arctic environment. In addition, the possible exploitation of the Arctic region by natural resource exploration and extractive industries presents a relatively new threat to the radiological status of the region. Despite the large amount of work in the field of terrestrial radioecology over the past 20 years, the Arctic remains worthy of special consideration as it is subject to conditions that may not have been accounted for during these previous studies. If so, terrestrial Arctic radioecology would appear to warrant further attention, with a view toward a better understanding of Arctic radioecological processes, thereby enabling greater protection of this special environment from future contamination events.

Observations of biota in Stepovogo Fjord, Novaya Zemlya, a former dumping site for radioactive waste

Stepovogo Fjord, located on the eastern coast of Novaya Zemlya, is an important former Soviet Union dumping site for radioactive waste. There is little information available on marine biota in this area. Better knowledge on the structure of marine food webs will allow for more accurate assessments of the consequences of any potential radioactive releases from the dumped waste. This article describes the occurrence, size and age distribution and diet of fish species collected in Stepovogo Fjord in 2012. The occurrence of macroalgae and other benthic species is also described. The fish fauna was dominated by the demersal fishes navaga (Eleginus nawaga) and shorthorn sculpin (Myoxocephalus scorpius). Navaga preyed mainly on benthic invertebrates, while sculpin preyed mainly on other fish species. A single individual of Atlantic cod (Gadus morhua) was also observed. Shorthorn sculpin and Atlantic cod have not previously been reported so far north in the Kara Sea. All taxa of macroalgae and benthic invertebrates observed in Stepovogo Fjord are common to the western coast of Novaya Zemlya and/or other areas in the Arctic. Currently there is no fishing activity in the immediate area in or around Stepovogo Fjord and only little commercial fishing in the Kara Sea due to the low commercial value of the species found in the area. Navaga and shorthorn sculpin do not make extensive migrations. As a result, the potential for the transfer of radioactive contamination to humans from consumption of fish and other seafood from this area is low at present.

The impact of tidal and mesoscale eddy advection on the long term dispersion of 99Tc from Sellafield

In the present work, numerical models are used to study the fate of the 99Tc discharges from Sellafield with a specific focus on the role of mesoscale eddy and tidal advection on the transport and dispersion of this radionuclide. Transport estimates are made with an ocean model that resolves a large part of the ocean mesoscale eddy field and also includes tides. Equivalent estimates are also computed with another model in which these processes are either absent or parametrized. Comparison with field observations shows that the coarse-resolution model can reproduce the general features of the observed time-space 99Tc distribution if the diffusivity in its eddy parametrization scheme is suitably chosen. However, the eddy-permitting simulations capture regional details better and show an overall higher prediction skill, with the model predictions agreeing with the observations within a factor of two to four. The importance of tidal advection is investigated by comparing transport in the eddy-permitting model when this is run either with tides included or with tides filtered out. The results point to systematic Lagrangian tidal drift in the Irish Sea and the North Sea that eventually impacts the 99Tc activity concentration levels also far downstream.