ICRP Publication 136
Dose Coefficients for Non-human Biota Environmentally Exposed to Radiation
Recommended citation
ICRP, 2017. Dose coefficients for nonhuman biota environmentally exposed to radiation. ICRP Publication 136. Ann. ICRP 46(2).
Authors on behalf of ICRP
A. Ulanovsky, D. Copplestone, J. Vives i Batlle
Abstract - The diversity of non-human biota is a specific challenge when developing and applying dosimetric models for assessing exposures of flora and fauna from radioactive sources in the environment. Dosimetric models, adopted in Publication 108, provide dose coefficients (DCs) for a group of reference entities [Reference Animals and Plants (RAPs)]. The DCs can be used to evaluate doses and dose rates, and to compare the latter with derived consideration reference levels (DCRLs), which are bands of dose rate where some sort of detrimental effect in a particular RAP may be expected to occur following chronic, long-term radiation exposure, as outlined in Publication 124. These dosimetric models pragmatically assume simple body shapes with uniform composition and density, homogeneous internal contamination, limited sets of idealised sources of external exposure to ionising radiation for aquatic and terrestrial animals and plants, and truncated radioactive decay chains. This pragmatic methodology is further developed and systematically extended in this publication, which supersedes the DC values of Publication 108. Significant methodological changes since Publication 108 include: implementation of a new approach for external exposure of terrestrial animals with an extended set of environmental radioactive sources in soil and in air; considering an extended range of organisms and locations in contaminated terrain; transition to the contemporary radionuclide database of Publication 107; assessment-specific consideration of the contribution of radioactive progeny to DCs of parent radionuclides; and use of generalised allometric relationships in the estimation of biokinetic or metabolic parameter values. These methodological developments result in changes to previously published tables of DCs for RAPs, and revised values are provided in this publication. This publication is complemented by a new software tool, called BiotaDC, which enables the calculation of DCs for internal and external exposures of organisms with user-defined masses, shapes, and locations in the environment and for all radionuclides in Publication 107.
© 2017 ICRP. Published by SAGE.
Keywords: Non-human biota; Radiological protection of the environment; Dose coefficients; Reference Animals and Plants; Dosimetry.
AUTHORS ON BEHALF OF ICRP A. ULANOVSKY, D. COPPLESTONE, J. VIVES I BATLLE
Key Points
The dosimetric approach adopted by the International Commission on Radiological Protection (ICRP) for use in environmental protection was introduced in Publication 108 (ICRP, 2008b). Since then, further developments have required substantial revisions. The current publication presents the revised and extended ICRP dosimetric framework for non-human biota, and supersedes the dose coefficient (DC) values in Annex C of Publication 108.
The DCs for external exposure of terrestrial biota have been substantially revised and extended. The current DCs are applicable to organisms with body masses in the range from 1 mg to 1000 kg, at heights above the ground surface from 0.1 to 500 m, for five types of environmental sources in soil and in ambient air. The text provides guidance on how to develop DCs via interpolation of the published values for life stages with masses between 1 mg and 1000 kg.
The DC computational framework transitioned from the radionuclide emission data of Publication 38 (ICRP, 1983) to the contemporary dataset of Publication 107 (ICRP, 2008a). The absorbed fractions and DCs for photons and electrons have been extended to maximum energy of 10 MeV to address radionuclide properties in the new database.
This publication is supplemented by tables of DCs for Reference Animals and Plants (RAPs). The data are compatible with those published previously, but have been recalculated with the new radionuclide emission data and presented in a new radionuclide-based layout, which highlights interspecies and intersource variability of DCs, thus facilitating interpolation of DCs for practical dose assessments.
This publication discusses alternative methods of accounting for contributions of radioactive progeny to DCs. A method that uses the ratio of time-integrated activities of the parent radionuclide and its radioactive progeny is shown as ‘fit for purpose’ for practical dose assessment tasks.
This publication introduces the software tool BiotaDC, which is designed to allow assessment of DCs for user-defined types of biota exposed to any radionuclide in the current database. The tool provides various approaches to the inclusion of contributions from radioactive progeny.
This publication introduces some allometric equations for mammals, formulated using a generalised approach that takes into account curvatures in the observed allometric relationships as well as quantifying their uncertainties.
Executive Summary: Not included in this publication
Concise Summary
Radiation dose assessment for the purposes of environmental radiological protection is challenged by diversity of living non-human organisms and variety of irradiation conditions. In 2007, ICRP, in its Publication 108, specified the concept of Reference Animals and Plants (RAPs) and introduced the dosimetric methodology for biota, including a dataset of the dose coefficients (DCs) for main radionuclides and exposure situations. In 2017, this methodology was further advanced and presented in Publication 136. Notably, the DCs for terrestrial organisms were revised and extended; the contemporary radionuclide database was used; alternative techniques to account for effect of radioactive progeny were added; and the printed DC tables were complemented by an online software to calculate user-defined DCs for arbitrary organisms, radionuclides and exposure conditions.
General Summary
For almost a century, the International Commission on Radiological Protection (ICRP) has been developing a scientific framework for the system of human radiation protection. Radiological protection of the environment was recognized as a required component of a comprehensive protection framework in the end of 20th century, resulting in appearance of the ICRP Publication 91 in 2003, followed by a series of publications addressing the principles of the environmental protection, the dose assessment methodology and relevant data. Assessing radiation doses for environmental species is challenged by extreme variability of different kinds of non-human biota and the environmental conditions they are exposed in. Unlike dosimetry for human beings, the dosimetry for animals and plants should be capable of addressing a wider range of body sizes, shapes and masses, organisms’ morphology and biokinetic, irradiation conditions and exposure pathways.
ICRP framework for non-human biota dose assessment was first introduced in the Publication 108 (2008), where the system of the Reference Animals and Plants (RAP) was specified, accompanied by a set of the dose coefficients (DC) for these entities in different exposure conditions. Although well received and widely used (e.g., the approach was implemented in the ERICA Tool in 2008), the Publication 108 approach had limitations with regard to the number of considered radionuclides, masses of the terrestrial organisms, radiation sources and consideration of decay chains under non-equilibrium conditions. These limitations were addressed in the ICRP Publication 136 (2017), which delivered significant methodological improvements, provided an extended DC dataset and a new online tool for DC calculation.
The dosimetry methodology underlying the DC data in the Publication 136 benefits from improved and extended set of the external DCs for terrestrial organisms with body masses varying from 1 mg to 1 ton exposed to radiation sources in soil or air at any heights up to 500 m above the ground interface. The DCs in the Publication 136 were computed using radionuclide emission data from the contemporary and comprehensive ICRP radionuclide database (ICRP, 2007), allowing to account for contributions of the parent and daughter radionuclides under various conditions in the decay chain. The printed tables of the new improved DCs were presented for the same RAPs (ICRP 2008) but with a new layout which facilitated easy interpolation of the DC between various RAPs, thus addressing many comments and questions being raised in the research community. The Publication 136 was complemented by an online software tool BiotaDC, which allowed calculation of DCs for user-defined organisms different from RAPs, for any radionuclides from the comprehensive database, accounting for an effect of radioactive progeny under different conditions of secular or transient equilibriums or a simple pragmatic approach from Publication 108. This online tool is freely available (http://biotadc.icrp.org/) at the ICRP webpage. From 2021, the dose calculation engine in the ERICA Tool version 2 became fully coherent to the ICRP approach and numerically compatible with the BiotaDC tool.
Technical Summary
The International Commission on Radiological Protection (ICRP) recognised the need in a comprehensive and coherent radiation protection framework, common for human and the environmental non-human species. In 2003, ICRP Publication 91 (ICRP, 2003) proposed the concept and identified main components of a framework for assessment of radiation impact on non-human species and was followed by a series of other publications specifying dose assessment techniques, radiation effects and practical application in different exposure situations (ICRP, 2008; 2009; 2014; 2017; 2020; 2021). Current ICRP activities on development of the new revised recommendations by 2030s develop towards establishing of a holistic comprehensive approach for human and environmental radiological protection. The ICRP framework for assessment of radiation doses for non-human organisms exposed in the environment was introduced in Publication 108 (ICRP, 2008), where the concept of the reference organisms was specified and presented. However, this publication did not consider situations of radiation exposure of pets, livestock and other animals and plants due to veterinary practices or other anthropogenic activities. Publication 136 (ICRP, 2017) further developed the framework and presented the updated dose coefficients (DC), data, and tools.
Dosimetry for non-human biota exposed to radiation sources in the environment is challenged by extreme variability of living forms, their morphology, biology, living conditions and exposure situations. Therefore, it was suggested (ICRP, 2003) for practical assessment tasks to establish a set of reference models, called Reference Animals and Plants (RAP), for which the DCs can be calculated for a number of generic irradiation geometries, pragmatically approximating the RAPs by simple geometrical shapes, conservatively neglecting radionuclide biokinetic inside the organism and using simplified truncated decay chains to account for the effect of radioactive progeny (ICRP, 2008). The DCs were developed (ICRP, 2008) for aquatic and terrestrial RAPs, for internal and external exposure and published for most relevant radionuclides. The DC values were complemented by fractions created by various types of radiation emitted in radioactive decay, thus providing possibility to easily apply different radiation weighting factors for weakly and densely ionising radiations (low- and high energy electrons and photons, alpha particles, fission fragments and recoil nuclei) to calculate radiation-weighted absorbed doses in practical assessment tasks.
The dataset in Publication 108 was well received and became integrated into the de-facto world standard ERICA Tool (Brown et al, 2008). However, these datasets were found insufficient or limited for some studies, requesting for DCs for organisms, radionuclides or irradiation situations not represented in Publication 108. Correspondingly, the improvement of the dosimetry framework continued, resulting in Publication 136 (ICRP, 2017), which closed several methodological gaps, extended the range of the irradiation situations for terrestrial organisms and provided the software tool for user-specific goals.
In Publication 136, the pragmatic methodology of the preceding publication was retained, further developed, and systematically extended, resulting in a new set of the DCs, superseding those in Publication 108. Significant methodological changes since Publication 108 included:
• Implementation of a new approach for external exposure of terrestrial animals with an extended set of environmental radioactive sources in soil and in air. The current external DCs for terrestrial organisms became compatible to the internal DCs and applicable to organisms with body masses in the range from 1 mg to 1000 kg, at heights above the ground surface from 0.1 to 500 m, for five types of environmental sources in soil and in ambient air.
• A guidance was given on how to develop external and internal DCs via interpolation of the published values for aquatic life stages with masses below 1 mg and above 1000 kg.
• Peculiarities of application of the DCs in practical dose assessment tasks were discussed. The simplified methods of accounting for redistribution and retention of radionuclides in the organism body were outlined and the generalised allometric relationships were introduced and suggested.
• The DC computational framework transitioned from the radionuclide emission data of Publication 38 (ICRP, 1983) to the comprehensive dataset for 1252 radionuclides of 97 elements in Publication 107 (ICRP, 2008a). The absorbed fractions and DCs for photons and electrons have been recalculated and extended to maximum energy of 10 MeV to address radionuclide properties in the new database.
• Alternative methods of accounting for contributions of radioactive progeny to DCs, including ratios of time-integrated or transient activities of the parent and daughter radionuclides. The old method of truncated decay chains retained for backward compatibility with Publication 108. The method that uses the ratio of time-integrated activities of the parent radionuclide and its radioactive progeny was shown as ‘fit for purpose’ for practical dose assessment tasks for non-human biota.
• Tables of DCs for Reference Animals and Plants (RAPs) were presented in the form compatible with those published previously in Publication 108, but the DC values were recalculated with the new radionuclide emission data and presented in a new radionuclide-based layout, which highlights interspecies and inter-source variability of DCs, thus facilitating interpolation of DCs for practical dose assessments.
• The online software tool BiotaDC was developed and runs at the ICRP webpage, providing open access to assessment of DCs for user-defined types of biota exposed to radiations from any of 1252 radionuclides in the current database. The tool allows for use of various approaches to the inclusion of contributions from radioactive progeny. Since 2021, the new ERICA Tool 2.0 incorporated the dose computation engine of the BiotaDC tool and became digitally compatible to Publication 136.
ICRP, 2017. Dose coefficients for nonhuman biota environmentally exposed to radiation. ICRP Publication 136. Ann. ICRP 46(2).
Authors on behalf of ICRP
A. Ulanovsky, D. Copplestone, J. Vives i Batlle
Abstract - The diversity of non-human biota is a specific challenge when developing and applying dosimetric models for assessing exposures of flora and fauna from radioactive sources in the environment. Dosimetric models, adopted in Publication 108, provide dose coefficients (DCs) for a group of reference entities [Reference Animals and Plants (RAPs)]. The DCs can be used to evaluate doses and dose rates, and to compare the latter with derived consideration reference levels (DCRLs), which are bands of dose rate where some sort of detrimental effect in a particular RAP may be expected to occur following chronic, long-term radiation exposure, as outlined in Publication 124. These dosimetric models pragmatically assume simple body shapes with uniform composition and density, homogeneous internal contamination, limited sets of idealised sources of external exposure to ionising radiation for aquatic and terrestrial animals and plants, and truncated radioactive decay chains. This pragmatic methodology is further developed and systematically extended in this publication, which supersedes the DC values of Publication 108. Significant methodological changes since Publication 108 include: implementation of a new approach for external exposure of terrestrial animals with an extended set of environmental radioactive sources in soil and in air; considering an extended range of organisms and locations in contaminated terrain; transition to the contemporary radionuclide database of Publication 107; assessment-specific consideration of the contribution of radioactive progeny to DCs of parent radionuclides; and use of generalised allometric relationships in the estimation of biokinetic or metabolic parameter values. These methodological developments result in changes to previously published tables of DCs for RAPs, and revised values are provided in this publication. This publication is complemented by a new software tool, called BiotaDC, which enables the calculation of DCs for internal and external exposures of organisms with user-defined masses, shapes, and locations in the environment and for all radionuclides in Publication 107.
© 2017 ICRP. Published by SAGE.
Keywords: Non-human biota; Radiological protection of the environment; Dose coefficients; Reference Animals and Plants; Dosimetry.
AUTHORS ON BEHALF OF ICRP A. ULANOVSKY, D. COPPLESTONE, J. VIVES I BATLLE
Key Points
The dosimetric approach adopted by the International Commission on Radiological Protection (ICRP) for use in environmental protection was introduced in Publication 108 (ICRP, 2008b). Since then, further developments have required substantial revisions. The current publication presents the revised and extended ICRP dosimetric framework for non-human biota, and supersedes the dose coefficient (DC) values in Annex C of Publication 108.
The DCs for external exposure of terrestrial biota have been substantially revised and extended. The current DCs are applicable to organisms with body masses in the range from 1 mg to 1000 kg, at heights above the ground surface from 0.1 to 500 m, for five types of environmental sources in soil and in ambient air. The text provides guidance on how to develop DCs via interpolation of the published values for life stages with masses between 1 mg and 1000 kg.
The DC computational framework transitioned from the radionuclide emission data of Publication 38 (ICRP, 1983) to the contemporary dataset of Publication 107 (ICRP, 2008a). The absorbed fractions and DCs for photons and electrons have been extended to maximum energy of 10 MeV to address radionuclide properties in the new database.
This publication is supplemented by tables of DCs for Reference Animals and Plants (RAPs). The data are compatible with those published previously, but have been recalculated with the new radionuclide emission data and presented in a new radionuclide-based layout, which highlights interspecies and intersource variability of DCs, thus facilitating interpolation of DCs for practical dose assessments.
This publication discusses alternative methods of accounting for contributions of radioactive progeny to DCs. A method that uses the ratio of time-integrated activities of the parent radionuclide and its radioactive progeny is shown as ‘fit for purpose’ for practical dose assessment tasks.
This publication introduces the software tool BiotaDC, which is designed to allow assessment of DCs for user-defined types of biota exposed to any radionuclide in the current database. The tool provides various approaches to the inclusion of contributions from radioactive progeny.
This publication introduces some allometric equations for mammals, formulated using a generalised approach that takes into account curvatures in the observed allometric relationships as well as quantifying their uncertainties.
Executive Summary: Not included in this publication
Concise Summary
Radiation dose assessment for the purposes of environmental radiological protection is challenged by diversity of living non-human organisms and variety of irradiation conditions. In 2007, ICRP, in its Publication 108, specified the concept of Reference Animals and Plants (RAPs) and introduced the dosimetric methodology for biota, including a dataset of the dose coefficients (DCs) for main radionuclides and exposure situations. In 2017, this methodology was further advanced and presented in Publication 136. Notably, the DCs for terrestrial organisms were revised and extended; the contemporary radionuclide database was used; alternative techniques to account for effect of radioactive progeny were added; and the printed DC tables were complemented by an online software to calculate user-defined DCs for arbitrary organisms, radionuclides and exposure conditions.
General Summary
For almost a century, the International Commission on Radiological Protection (ICRP) has been developing a scientific framework for the system of human radiation protection. Radiological protection of the environment was recognized as a required component of a comprehensive protection framework in the end of 20th century, resulting in appearance of the ICRP Publication 91 in 2003, followed by a series of publications addressing the principles of the environmental protection, the dose assessment methodology and relevant data. Assessing radiation doses for environmental species is challenged by extreme variability of different kinds of non-human biota and the environmental conditions they are exposed in. Unlike dosimetry for human beings, the dosimetry for animals and plants should be capable of addressing a wider range of body sizes, shapes and masses, organisms’ morphology and biokinetic, irradiation conditions and exposure pathways.
ICRP framework for non-human biota dose assessment was first introduced in the Publication 108 (2008), where the system of the Reference Animals and Plants (RAP) was specified, accompanied by a set of the dose coefficients (DC) for these entities in different exposure conditions. Although well received and widely used (e.g., the approach was implemented in the ERICA Tool in 2008), the Publication 108 approach had limitations with regard to the number of considered radionuclides, masses of the terrestrial organisms, radiation sources and consideration of decay chains under non-equilibrium conditions. These limitations were addressed in the ICRP Publication 136 (2017), which delivered significant methodological improvements, provided an extended DC dataset and a new online tool for DC calculation.
The dosimetry methodology underlying the DC data in the Publication 136 benefits from improved and extended set of the external DCs for terrestrial organisms with body masses varying from 1 mg to 1 ton exposed to radiation sources in soil or air at any heights up to 500 m above the ground interface. The DCs in the Publication 136 were computed using radionuclide emission data from the contemporary and comprehensive ICRP radionuclide database (ICRP, 2007), allowing to account for contributions of the parent and daughter radionuclides under various conditions in the decay chain. The printed tables of the new improved DCs were presented for the same RAPs (ICRP 2008) but with a new layout which facilitated easy interpolation of the DC between various RAPs, thus addressing many comments and questions being raised in the research community. The Publication 136 was complemented by an online software tool BiotaDC, which allowed calculation of DCs for user-defined organisms different from RAPs, for any radionuclides from the comprehensive database, accounting for an effect of radioactive progeny under different conditions of secular or transient equilibriums or a simple pragmatic approach from Publication 108. This online tool is freely available (http://biotadc.icrp.org/) at the ICRP webpage. From 2021, the dose calculation engine in the ERICA Tool version 2 became fully coherent to the ICRP approach and numerically compatible with the BiotaDC tool.
Technical Summary
The International Commission on Radiological Protection (ICRP) recognised the need in a comprehensive and coherent radiation protection framework, common for human and the environmental non-human species. In 2003, ICRP Publication 91 (ICRP, 2003) proposed the concept and identified main components of a framework for assessment of radiation impact on non-human species and was followed by a series of other publications specifying dose assessment techniques, radiation effects and practical application in different exposure situations (ICRP, 2008; 2009; 2014; 2017; 2020; 2021). Current ICRP activities on development of the new revised recommendations by 2030s develop towards establishing of a holistic comprehensive approach for human and environmental radiological protection. The ICRP framework for assessment of radiation doses for non-human organisms exposed in the environment was introduced in Publication 108 (ICRP, 2008), where the concept of the reference organisms was specified and presented. However, this publication did not consider situations of radiation exposure of pets, livestock and other animals and plants due to veterinary practices or other anthropogenic activities. Publication 136 (ICRP, 2017) further developed the framework and presented the updated dose coefficients (DC), data, and tools.
Dosimetry for non-human biota exposed to radiation sources in the environment is challenged by extreme variability of living forms, their morphology, biology, living conditions and exposure situations. Therefore, it was suggested (ICRP, 2003) for practical assessment tasks to establish a set of reference models, called Reference Animals and Plants (RAP), for which the DCs can be calculated for a number of generic irradiation geometries, pragmatically approximating the RAPs by simple geometrical shapes, conservatively neglecting radionuclide biokinetic inside the organism and using simplified truncated decay chains to account for the effect of radioactive progeny (ICRP, 2008). The DCs were developed (ICRP, 2008) for aquatic and terrestrial RAPs, for internal and external exposure and published for most relevant radionuclides. The DC values were complemented by fractions created by various types of radiation emitted in radioactive decay, thus providing possibility to easily apply different radiation weighting factors for weakly and densely ionising radiations (low- and high energy electrons and photons, alpha particles, fission fragments and recoil nuclei) to calculate radiation-weighted absorbed doses in practical assessment tasks.
The dataset in Publication 108 was well received and became integrated into the de-facto world standard ERICA Tool (Brown et al, 2008). However, these datasets were found insufficient or limited for some studies, requesting for DCs for organisms, radionuclides or irradiation situations not represented in Publication 108. Correspondingly, the improvement of the dosimetry framework continued, resulting in Publication 136 (ICRP, 2017), which closed several methodological gaps, extended the range of the irradiation situations for terrestrial organisms and provided the software tool for user-specific goals.
In Publication 136, the pragmatic methodology of the preceding publication was retained, further developed, and systematically extended, resulting in a new set of the DCs, superseding those in Publication 108. Significant methodological changes since Publication 108 included:
• Implementation of a new approach for external exposure of terrestrial animals with an extended set of environmental radioactive sources in soil and in air. The current external DCs for terrestrial organisms became compatible to the internal DCs and applicable to organisms with body masses in the range from 1 mg to 1000 kg, at heights above the ground surface from 0.1 to 500 m, for five types of environmental sources in soil and in ambient air.
• A guidance was given on how to develop external and internal DCs via interpolation of the published values for aquatic life stages with masses below 1 mg and above 1000 kg.
• Peculiarities of application of the DCs in practical dose assessment tasks were discussed. The simplified methods of accounting for redistribution and retention of radionuclides in the organism body were outlined and the generalised allometric relationships were introduced and suggested.
• The DC computational framework transitioned from the radionuclide emission data of Publication 38 (ICRP, 1983) to the comprehensive dataset for 1252 radionuclides of 97 elements in Publication 107 (ICRP, 2008a). The absorbed fractions and DCs for photons and electrons have been recalculated and extended to maximum energy of 10 MeV to address radionuclide properties in the new database.
• Alternative methods of accounting for contributions of radioactive progeny to DCs, including ratios of time-integrated or transient activities of the parent and daughter radionuclides. The old method of truncated decay chains retained for backward compatibility with Publication 108. The method that uses the ratio of time-integrated activities of the parent radionuclide and its radioactive progeny was shown as ‘fit for purpose’ for practical dose assessment tasks for non-human biota.
• Tables of DCs for Reference Animals and Plants (RAPs) were presented in the form compatible with those published previously in Publication 108, but the DC values were recalculated with the new radionuclide emission data and presented in a new radionuclide-based layout, which highlights interspecies and inter-source variability of DCs, thus facilitating interpolation of DCs for practical dose assessments.
• The online software tool BiotaDC was developed and runs at the ICRP webpage, providing open access to assessment of DCs for user-defined types of biota exposed to radiations from any of 1252 radionuclides in the current database. The tool allows for use of various approaches to the inclusion of contributions from radioactive progeny. Since 2021, the new ERICA Tool 2.0 incorporated the dose computation engine of the BiotaDC tool and became digitally compatible to Publication 136.
