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N. A. Beresford,
C. L. Barnett,
J. E. Brown,
J. J. Cheng,
D. Copplestone,
V. Filistovic,
A. Hosseini,
B. J. Howard,
S. R. Jones,
S. Kamboj,
A. Kryshev,
T. Nedveckaite,
G. Olyslaegers, R. Saxén,
T. Sazykina,
J. Vives i Batlle,
S. Vives-Lynch,
T. Yankovich,
C. Yu
[show abstract]
[hide abstract]
ABSTRACT: A number of models have recently been, or are currently being, developed to enable the assessment of radiation doses from
ionising radiation to non-human species. A key component of these models is the ability to predict whole-organism activity
concentrations in a wide range of wildlife. In this paper, we compare the whole-organism activity concentrations predicted
by eight models participating within the IAEA Environmental Modelling for Radiation Safety programme for a range of radionuclides
to terrestrial and freshwater organisms. In many instances, there was considerable variation, ranging over orders of magnitude,
between the predictions of the different models. Reasons for this variability (including methodology, data source and data
availability) are identified and discussed. The active participation of groups responsible for the development of key models
within this exercise is a useful step forward in providing the transparency in methodology and data provenance required for
models which are either currently being used for regulatory purposes or which may be used in the future. The work reported
in this paper, and supported by other findings, demonstrates that the largest contribution to variability between model predictions
is the parameterisation of their transfer components. There is a clear need to focus efforts and provide authoritative compilations
of those data which are available.
Biophysik 04/2012; 47(4):491-514. · 1.70 Impact Factor
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[show abstract]
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ABSTRACT: In Publication 103 (ICRP, 2007), the Commission included a section on the protection of the environment, and indicated that it would be further developing its approach to this difficult subject by way of a set of Reference Animals and Plants (RAPs) as the basis for relating exposure to dose, and dose to radiation effects, for different types of animals and plants. Subsequently, a set of 12 RAPs has been described in some detail (ICRP, 2008), particularly with regard to estimation of the doses received by them, at a whole-body level, in relation to internal and external radionuclide concentrations; and what is known about the effects of radiation on such types of animals and plants. A set of dose conversion factors for all of the RAPs has been derived, and the resultant dose rates can be compared with evaluations of the effects of dose rates using derived consideration reference levels (DCRLs). Each DCRL constitutes a band of dose rates for each RAP within which there is likely to be some chance of the occurrence of deleterious effects. Site-specific data on Representative Organisms (i.e. organisms of specific interest for an assessment) can then be compared with such values and used as a basis for decision making. It is intended that the Commission's approach to protection of the environment be applied to all exposure situations. In some situations, the relevant radionuclide concentrations can be measured directly, but this is not always possible or feasible. In such cases, modelling techniques are used to estimate the radionuclide concentrations. This report is an initial step in addressing the needs of such modelling techniques. After briefly reviewing the basic factors relating to the accumulation of radionuclides by different types of biota, in different habitats, and at different stages in the life cycle, this report focuses on the approaches used to model the transfer of radionuclides through the environment. It concludes that equilibrium concentration ratios (CRs) are most commonly used to model such transfers, and that they currently offer the most comprehensive data coverage. The report also reviews the methods used to derive CRs, and describes a means of summarising statistical information from empirical data sets. Emphasis has been placed on using data from field studies, although some data from laboratory experiments have been included for some RAPs. There are, inevitably, many data gaps for each RAP, and other data have been used to help fill these gaps. CRs specific to each RAP were extracted from a larger database, structured in terms of generic wildlife groups. In cases where data were lacking, values from taxonomically-related organisms were used to derive suitable surrogate values. The full set of rules which have been applied for filling gaps in RAP-specific CRs is described. Statistical summaries of the data sets are provided, and CR values for 39 elements and 12 RAP combinations are given. The data coverage, reliance on derived values, and applicability of the CR approach for each of the RAPs is discussed. Finally, some consideration is given to approaches where RAPs and their life stages could be measured for the elements of interest under more rigorously controlled conditions to help fill the current data gaps.
Annals of the ICRP 12/2009; 39(6):1-111.
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ABSTRACT: The process of assessing risk to the environment following a given release of radioactivity requires the quantification of activity concentrations in environmental media and reference organisms. The methodology adopted by the ERICA Integrated Approach involves the application of concentration ratios (CR values) and distribution coefficients (K(d) values) for aquatic systems. Within this paper the methodologies applied to derive default transfer parameters, collated within the ERICA Tool databases, are described to provide transparency and traceability in the documentation process. Detailed information is provided for the CR values used for marine and freshwater systems. Of the total 372 CR values derived for the marine ecosystem, 195 were identified by literature review. For the freshwater system, the number of values based on review was less, but still constituted 129 from a total of 372 values. In both types of aquatic systems, 70-80% of the data gaps have been filled by employing "preferable" approaches such as those based on substituting values from taxonomically similar organisms or biogeochemically similar elements.
Journal of Environmental Radioactivity 04/2008; 99(9):1408-29. · 1.34 Impact Factor
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[show abstract]
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ABSTRACT: A framework for protection of the environment is likely to require a methodology for assessing dose rates arising from naturally occurring radionuclides. This paper addresses this issue for European aquatic environments through a process of (a) data collation, mainly with respect to levels of radioactivity in water sediments and aquatic flora and fauna, (b) the use of suitable distribution coefficients, concentration factors and global data where data gaps are present and (c) the utilisation of a reference organism approach whereby a finite number of suitable geometries are selected to allow dose per unit concentration factors to be derived and subsequent absorbed dose calculations (weighted or unweighted) to be made. The majority of the calculated absorbed dose, for both marine and freshwater organisms, arises from internally incorporated alpha emitters, with 210Po and 226Ra being the major contributors. Calculated doses are somewhat higher for freshwater compared to marine organisms, and the range of doses is also much greater. This reflects both the much greater variability of radionuclide concentrations in freshwater as compared to seawater, and also variability or uncertainty in concentration factor values. This work has revealed a number of substantial gaps in published empirical data especially for European aquatic environments.
Journal of Radiological Protection 01/2005; 24(4A):A63-77. · 1.39 Impact Factor
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[show abstract]
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ABSTRACT: The content of 137Cs in fallout, fish, and water was measured with the aim to study the role of site-specific parameters on the transfer of 137Cs into fishes. The temporal changes of 137Cs and 90Sr in various types of fishes were studied at two sites of Lake Saimaa. The 137Cs content in fishes in the Ukonvesi area, which is the north-western part of the lake, was clearly lower than that in the southern parts of the lake, in Ala-Saimaa, although the fallout of 137Cs to the Ukonvesi area was somewhat higher than that to Ala-Saimaa. The fallout in 1986 was about 6 kBq m-
2 to the Ukonvesi area and about 3 kBq m-
2 to the southern parts of the lake. The 137Cs content in fishes was the highest in 1988-1989 in Ala-Saimaa, approximately 700 Bq kg-
1, while that in the Ukonvesi area was only about 300 Bq kg-
1, where the values were the highest in 1987. In Ukonvesi the 137Cs content in fishes decreased rapidly, being already in 1990 almost at the same level as in 2000. In the southern parts of the lake the decrease in the 137Cs content in fishes was much slower. Also the 90Sr content in fishes in Ukonvesi was lower than that in Ala-Saimaa. The 137Cs content of the water in the Ukonvesi area decreased rapidly, being about 7 Bq m-
3 in 1998, while that in the lower areas of the lake was still 15 Bq m-
3 in 2000. The 90Sr content in water was approximately the same at the both sampling sites (7-8 Bq m-
3). The water chemical parameters, such as potassium, total phosphorus, total nitrogen, chlorophyll a, and electrical conductivity were significantly higher in Ukonvesi than in Ala-Saimaa.
Radiochemistry 08/2001; 43(5):487-491.
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ABSTRACT: The total amounts of 137Cs and 90Sr transported from Finland by rivers into the Gulf of Finland, Gulf of Bothnia and Archipelago Sea since 1986 were estimated. The estimates were based on long-term monitoring of 137Cs and 90Sr in river and other surface waters and on the statistics of water discharges from Finnish rivers to the above sub-areas of the Baltic Sea. The total amounts of 137Cs and 90Sr removed from Finland into the Baltic Sea during 1986-1996 were estimated to be 65 and 10 TBq, respectively. The results show that, although the deposition of 137Cs was much higher than that of 90Sr after the Chernobyl accident, the amount of 137Cs removed from Finland is only six times as high as that of 90Sr. This emphasizes the importance of 90Sr while considering radiation doses from surface waters and 137Cs while estimating doses via pathways from catchment soil, lake sediments and biota after a fallout situation.
Journal of Environmental Radioactivity 02/2001; 54(2):275-91. · 1.34 Impact Factor
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http://dx.doi.org/10.1051/radiopro/2002176.
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ABSTRACT: The deposition from Chernobyl in spring 1986 was most unevenly distributed in Finland and elevated the $^{137}$Cs contents of fishes in Finnish lakes significantly. High activity concentrations of $^{137}$Cs still occur in fish from certain lakes in the areas of the highest deposition. Activity concentrations of $^{137}$Cs in perch varied from 20 to 7 800 and those in lake water from 4 to 330 Bq/m$^{3}$ in 1998 and 2002. Concentration factors (Bq/kg in perch / Bq/kg in lake water) ranged from 1 300 to 30 000 in the lakes studied. Ecological halftimes of $^{137}$Cs in perch in certain lakes, monitored regularly since 1986, and representing different types in terms of environmental transfer, were estimated as examples. The longest halftimes of $^{137}$Cs in perch were approximately 8 years and the shortest approximately 3 years determined for the time period of 1988-2002. Except for estimation of radiation doses to people eating fish, data on changes of activity concentrations in various parts of the aquatic system are also needed when estimating radiation doses to fish and other biota. Slow recovery of the habitat and feed from $^{137}$Cs results in higher exposure of biota than in case of rapid activity decrease.
http://dx.doi.org/10.1051/radiopro:2005s1-095.
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R. Saxén
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ABSTRACT: STUK-A77 Changes over time in the activity concentrations of radionuclides in surface water were monitored as in the previous year. Monitoring of the radioactivity transported by the largest rivers to the Baltic Sea was also continued. All samples were analysed gammaspectrometrically and for 90Sr. Some water samples were analysed for tritium. The dominant gamma-emitting radionuclides were 137Cs and 134Cs. The uneven distribution of Chernobyl deposition is still seen in the results. The activity concentrations of 137Cs have decreased significantly. The study on areal and temporal changes in the activity concentrations of 137Cs in fish was expanded in 1987. In all about 1550 samples were analysed gammaspectrometrically, and a few samples were also analysed radiochemically for 90Sr. Fifteen different fish species were included in the study. The highest activity concentrations of 137Cs were detected in small oligotrophic lakes in the area of highest deposition. The level of 137Cs in non-predatory fish had clearly decreased, while that in predatory fish was almost double what it had been in 1986. Activity concentrations of 137Cs in semi-predatory fish were also slightly higher than in 1986.
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N A Beresford,
C L Barnett,
J E Brown,
J-J Cheng,
D Copplestone,
V Filistovic,
A Hosseini,
B J Howard,
S R Jones,
S Kamboj,
A. Kryshev,
T Nedveckaite,
Geert Olyslaegers, R Saxén,
T Sazykina,
J Vives I Batlle,
S Vives-Lynch,
T Yankovich,
C Yu
[show abstract]
[hide abstract]
ABSTRACT: A number of models have recently been, or are currently being, developed to enable the assessment of radiation doses from ionising radiation to non-human species. A key component of these models is the ability to predict whole-organism activity concentrations in a wide range of wildlife. In this paper, we compare the wholeorganism activity concentrations predicted by eight models participating within the IAEA Environmental Modelling for Radiation Safety programme for a range of radionuclides to terrestrial and freshwater organisms.
