Task Group 99
Reference Animal and Plant (RAP) Monographs

A Task Group under Committee 1 and Committee 4

(The Terms of Reference of this Task Group were revised in January 2022)


Initiated under the auspices of the former Committee 5, TG99 was developed from 2017 as a joint task group between Committee 1 and Committee 4, dealing with improvements in the field of radiological protection of the environment.

As originally defined, the goal of this TG is to review and update data and methods to improve the use and practicality of the ICRP Reference Animals and Plants (RAPs) when applying the system of radiological protection of the environment in planned, emergency and existing exposure situations.


  • A methodological report to describe methods used for meta-analysis and data sources (type and quality) for applying these methods to fauna and flora. (NB: The TG agreed that veterinary patients’ issues are out of scope of this report, even though a number of data will surely be useful for tackling this issue). This report will describe the statistical method for deriving Derived Consideration Reference Levels (DCRLs) values for the three exposure situations (planned, emergency and existing), advise on how to implement the method, and discuss the comparison of the outcomes with existing DCRLs.
  • A series of electronic annexes (excel files), one per wildlife group, where all the data used in the document will be made available in a stand-alone manner. The update will comprise the initial 12 RAPs as well as existing data on other non-RAP species supporting the effect data meta-analysis to derive DCRLs at a taxonomic level higher than the family, i.e. the class level. (e.g. data on rat and deer (2 of the current RAPs) will be updated and compile with all other data on mammals).

Evolution of the initial scope

The initial scope of the update of RAP-related data covered dosimetry, transfers and effects, with all relevant knowledge organised in a meaningful manner across the three main components of risk assessment: transfers and dosimetry, effects and risk characterization.

Since the TG99 began its work, two ICRP publications have been issued on dosimetry (Publication 136 and Publication 148) and the IAEA will issue in 2022 an update of Safety Report Series No. 19 “Generic models for use in assessing the impact of discharges of radioactive substances to the environment” (SRS 19). The latter will contain updated data for wildlife dose assessments (i.e. radionuclide transfers and dosimetry with a comprehensive set of modelling methods).

The limitations of the current system of protection were recognised by the application of the approach to real ecosystems, and extrapolation methods have been explored, in particular to fill the gaps in radionuclide transfer parameters for various organisms. However, the development of extrapolation methods to infer interspecies variation in radiosensitivity has been lacking to justify DCRL values with improved underlying datasets and systematic methods that reduce reliance on expert judgement. Therefore, recognizing that datasets on effects on non-human biota exist beyond the twelve RAP families, Task Group 99 has explored broadening the taxonomic representativeness of Reference Animals and Plants (RAP) from the family to the class level (e.g. the current RAP rat and deer would be grouped together under mammals (Class Mammalia); duck as bird (Class Aves)). To this end, the group examined and improved the quality of the Derived Consideration Reference Levels (DCRLs) by conceiving and implementing a systematic, generic, reproducible, and transparent statistical method for their derivation. Statistical extrapolation models to quantify the range of radiosensitivity of population-relevant endpoints within a taxonomic class, named Endpoint Sensitivity Distributions (ESD), were developed, making the best use of existing effects data, so that the scientific evidence is improved and the remaining uncertainties are quantified as far as possible.

The relevance of the DRCL values derived on the basis of the ESD per class is verified by comparison with more recent laboratory data and with data on the effects on flora and fauna in areas affected by the Fukushima Daiichi nuclear accident and the Chernobyl nuclear power plant accident.

The Task Group provided DCRLs by class in the form of ranges, the width of which is justified by the remaining uncertainties. Preliminary tests carried out by Task Group 105 have shown that these new DCRL ranges do not alter the conclusions of the risk assessment for the exposure situations predicted. Additional tests are underway for existing exposure situations.
The draft report will be made available for public consultation and finalisation of the publication process during 2025.



ICRP 2023 Poster

Jacqueline Garnier-Laplace (Chair), OECD Nuclear Energy Agency (NEA), France
Christelle Adam-Guillermin (Co-Chair), IRSN, France
Claire Cailes (Member), Environment Agency, United Kingdom
Frederic Alonzo (Member), French Institute for Radiological Protection and Nuclear Safety (IRSN), France
Karine Beaugelin-Seiller (Member), Institut de Radioprotection et de S�ret� Nucl�aire (IRSN), France
Justin Brown (Member), Norwegian Radiation and Nuclear Safety Authority (DSA), Norway
David Copplestone (Member), University of Stirling, United Kingdom
Kathryn A Higley (Member), Oregon State University, USA
Carl-Magnus Larsson (Member), Norwegian Radiation and Nuclear Safety Authority, Norway
Almudena Real (Member), CIEMAT, Spain
Per Strand (Member), Norwegian Radiation and Nuclear Safety Authority (DSA), Norway
Keiko Tagami (Member), National Institutes for Quantum Scienc and Technology, Japan
Momo Takada (Member), National Institute of Advanced Industrial Science and Technology (AIST), Japan
Claire Della Vedova (Member), French Institute for Radiological Protection and Nuclear Safety (IRSN), France
Jordi Vives Batlle (Member), Belgian Nuclear Research Centre (SCK CEN), Belgium
Tamara Yankovich (Member), Austria
Abdulkadir Alaydarous (Technical Secretary), USA
Diego Telleria (Representative), International Atomic Energy Agency (IAEA), Austria