ICRP Publication 114
Environmental Protection: Transfer Parameters for Reference Animals and Plants
Recommended citation
ICRP, 2009. Environmental Protection: Transfer Parameters for Reference Animals and Plants. ICRP Publication 114, Ann. ICRP 39(6)
Authors on behalf of ICRP
P. Strand, N. Beresford, D. Copplestone, J. Godoy, L. Jianguo, R. Saxén, T. Yankovich, J. Brown
Abstract - In Publication 103, 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, 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.
© 2011 ICRP Published by Elsevier Ltd. All rights reserved.
Keywords: Environmental protection; Reference Animals and Plants; Concentration ratios.
AUTHORS ON BEHALF OF EHALF OF ICRP P. STRAND, N. BERESFORD, D. COPPLESTONE OPPLESTONE, J. GODOY, L. JIANGUO, R. SAXEN , T. YANKOVICH, J. BROWN
References
ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP 37 (2–4).
ICRP, 2008. Environmental protection: the concept and use of reference animals and plants. ICRP Publication 108. Ann. ICRP 38 (4–6).
Key Points: Not included in this publication
Executive Summary
The Commission has based its approach to environmental protection on the use 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 in an internally consistent manner. The results of this approach have, to date, resulted in the derivation of a set of dose conversion factors for the RAPs. These dose conversion factors allow dose rates to be calculated when the concentrations of radionuclides within the RAPs and the surrounding media have been established. The resultant dose rates can then be compared with evaluations of the effects of dose rates on the different RAP types using the derived consideration reference levels outlined previously in Publication 108 (ICRP, 2008). Each derived consideration reference level constitutes a band of dose rates for each RAP within which there is likely to be some chance of deleterious effects occurring in individuals of that type of animal or plant. 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.
In many cases, however, direct measurements of the radionuclide concentrations in animals, plants, and the surrounding media are not available. As such, modelling techniques are often used to estimate radionuclide concentrations. Various databases have been compiled, over many years, relating to the transfer of radionuclides from environmental media to a wide range of biota, but these have been compiled primarily in order to estimate exposures to humans from their consumption. Such data therefore only usually apply to the edible parts of the relevant organisms, and to organisms that are edible. They do not, therefore, always relate to the type of organism, the life stage, or the tissue that is of interest with regard to the estimation of radiation effects. However, some data sets have been specifically derived to understand the metabolism of individual elements or radionuclides within different types of organisms; these are particularly useful but are rare.
Within this report, a number of methods that have traditionally been used to model environmental radionuclide transfer to organisms are described, and a method for deriving internal body activity concentrations in RAPs has been identified that uses empirically based concentration ratios (CRs) to relate activity concentrations in the organism to those in its environment. Equilibrium CRs are commonly used to model such transfers, and they currently offer the most comprehensive data coverage. This report describes the formulation of a database that has allowed the collation of data on whole-body CRs and, where applicable, data entry in relation to activity concentrations in organisms and habitat media independently. For use with the RAPs, emphasis has been placed on collating data from field studies, although data from laboratory experiments have also been included for some RAPs. The database is structured in terms of generic wildlife groups, but the data have also been attributed to the RAPs where possible. In this way, CRs specifically for RAPs were extracted and, in cases where transfer data were lacking, a data-gap-filling methodology (e.g. adopting values from taxonomically-related organisms) was used to derive suitable surrogate values. The full set of rules that 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 have been reported. The data coverage, reliance on derived values, and applicability of the CR approach for each of the RAPs is discussed. The results are, as to be expected, somewhat variable.
It is recognised that for radionuclides emitting relatively short-range radiations (such as alpha particles and low-energy beta radiations), and for organisms above a certain size and complexity, doses to radiosensitive tissues are likely to dictate the resultant radiation effect compared with the more commonly modelled whole body exposure. However, few studies have been published on the internal distributions of radionuclides for many of the RAPs, and there is a lack of data on transfer for the various RAP life stages. Suggested approaches for deriving surrogate transfer data for life stages are therefore outlined. 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.
Reference
ICRP, 2008. Environmental protection: the concept and use of reference animals and plants. ICRP Publication 108. Ann. ICRP 38 (4–6).
ICRP, 2009. Environmental Protection: Transfer Parameters for Reference Animals and Plants. ICRP Publication 114, Ann. ICRP 39(6)
Authors on behalf of ICRP
P. Strand, N. Beresford, D. Copplestone, J. Godoy, L. Jianguo, R. Saxén, T. Yankovich, J. Brown
Abstract - In Publication 103, 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, 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.
© 2011 ICRP Published by Elsevier Ltd. All rights reserved.
Keywords: Environmental protection; Reference Animals and Plants; Concentration ratios.
AUTHORS ON BEHALF OF EHALF OF ICRP P. STRAND, N. BERESFORD, D. COPPLESTONE OPPLESTONE, J. GODOY, L. JIANGUO, R. SAXEN , T. YANKOVICH, J. BROWN
References
ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP 37 (2–4).
ICRP, 2008. Environmental protection: the concept and use of reference animals and plants. ICRP Publication 108. Ann. ICRP 38 (4–6).
Key Points: Not included in this publication
Executive Summary
The Commission has based its approach to environmental protection on the use 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 in an internally consistent manner. The results of this approach have, to date, resulted in the derivation of a set of dose conversion factors for the RAPs. These dose conversion factors allow dose rates to be calculated when the concentrations of radionuclides within the RAPs and the surrounding media have been established. The resultant dose rates can then be compared with evaluations of the effects of dose rates on the different RAP types using the derived consideration reference levels outlined previously in Publication 108 (ICRP, 2008). Each derived consideration reference level constitutes a band of dose rates for each RAP within which there is likely to be some chance of deleterious effects occurring in individuals of that type of animal or plant. 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.
In many cases, however, direct measurements of the radionuclide concentrations in animals, plants, and the surrounding media are not available. As such, modelling techniques are often used to estimate radionuclide concentrations. Various databases have been compiled, over many years, relating to the transfer of radionuclides from environmental media to a wide range of biota, but these have been compiled primarily in order to estimate exposures to humans from their consumption. Such data therefore only usually apply to the edible parts of the relevant organisms, and to organisms that are edible. They do not, therefore, always relate to the type of organism, the life stage, or the tissue that is of interest with regard to the estimation of radiation effects. However, some data sets have been specifically derived to understand the metabolism of individual elements or radionuclides within different types of organisms; these are particularly useful but are rare.
Within this report, a number of methods that have traditionally been used to model environmental radionuclide transfer to organisms are described, and a method for deriving internal body activity concentrations in RAPs has been identified that uses empirically based concentration ratios (CRs) to relate activity concentrations in the organism to those in its environment. Equilibrium CRs are commonly used to model such transfers, and they currently offer the most comprehensive data coverage. This report describes the formulation of a database that has allowed the collation of data on whole-body CRs and, where applicable, data entry in relation to activity concentrations in organisms and habitat media independently. For use with the RAPs, emphasis has been placed on collating data from field studies, although data from laboratory experiments have also been included for some RAPs. The database is structured in terms of generic wildlife groups, but the data have also been attributed to the RAPs where possible. In this way, CRs specifically for RAPs were extracted and, in cases where transfer data were lacking, a data-gap-filling methodology (e.g. adopting values from taxonomically-related organisms) was used to derive suitable surrogate values. The full set of rules that 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 have been reported. The data coverage, reliance on derived values, and applicability of the CR approach for each of the RAPs is discussed. The results are, as to be expected, somewhat variable.
It is recognised that for radionuclides emitting relatively short-range radiations (such as alpha particles and low-energy beta radiations), and for organisms above a certain size and complexity, doses to radiosensitive tissues are likely to dictate the resultant radiation effect compared with the more commonly modelled whole body exposure. However, few studies have been published on the internal distributions of radionuclides for many of the RAPs, and there is a lack of data on transfer for the various RAP life stages. Suggested approaches for deriving surrogate transfer data for life stages are therefore outlined. 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.
Reference
ICRP, 2008. Environmental protection: the concept and use of reference animals and plants. ICRP Publication 108. Ann. ICRP 38 (4–6).
