Protection of the Environment under Different Exposure Situations

Draft document: Protection of the Environment under Different Exposure Situations
Submitted by Karla Petrová, State Office for Nuclear Safety, Czech Republic
Commenting on behalf of the organisation

Comments – the Czech Republic

The draft of the ICRP publication on „Protection od the environment under different exposure situation“  intends to shift the developments in this sector of protection forward and tries to include the radiation protection of non-human biota into the existing system of radiation protection of humans and proceed to definite regulatory system also in this area. The inclusion of this agenda into the system of radiation protection of humans in not fully justified. A new category of exposure is namely declared in addition to the existing occupational, public and medical exposures (of humans) whereas the environmental exposure is another modality of exposure not referred to the exposure of humans. Another difficulty is to find identical features in the application of “reference person” and “reference animals and plants.”

Two domains of questions should be clarified first:  what is the actual objective of the inclusion of the protection of biota into the established system of radiation protection of humans and further by what kind of approaches (methods, indicators) could be useful and effective as quantitative tools for setting the acceptability of  exposure of biota in the context of the preset objective of the protection.

What is the objective of the protection of biota in given context?  Clearly it is not the protection of an exposed individual (not considering possible exclusions based on different arguments)  but the preservation of species,  their habitats  and other conditions  related to the preservation of ecologic balance ( in the view of possible effect of the hurt of one species to other components of chains) and the preservation of the genetic diversity worldwide. This difference in the final  objective should have some restrained  impact on the tendency to construct the protection of biota similarly as the protection of humans.

As far as the choice of an approach for assessment  the acceptability of the exposure of biota is concerned, due to the inspiration from the good experience with the application  of the model of a “reference person” in  humans, the similar approach has been selected for biota. The regulation of doses or dose rates is guided using appropriate quantities calculated on the models of 9 species of the reference animals and 3 species of the reference plants. In the part 4 of the Annex of the draft the specific issues of the dosimetry,  biology, exposure situations etc. are discussed hinting to the high diversity and changeable features of radiosensitivity also between species not far from each other in the taxonomic system. The selection of a representative species and the assessment of their exposure and its relevance is connected with numerous pitfalls. The use of the daily dose rates, as the main quantity featuring the exposures seems to be rather impractical and inconsistent.  Moreover the values of dose rates  for particular species presented in the tables of the Appendix 1 put the question of where and under what conditions these figures might occur. In could be useful to quote some observations illustrating that the boxes in the tables indicating  “No  information”  have a chance to be later completed with data so far lacking. 

The draft claims correctly that three main principles of radiation protection should be applied in the protection of biota similarly as in protection of humans namely: justification, setting limits, optimisation. The draft shows rather in detail, how these principles are dealt with in protection of humans and less space is devoted to their specific application for the environment.  The “derived consideration levels”  fulfil for biota the task of the second point, i.e. regulation  using numerical standards.  Specified guidelines how apply the principle of optimisation in the protection of biota are, however, lacking. It is almost limited only to the general statement of the need of permanent alertness towards decreasing the doses where possible.  

The draft does not submit any broader analysis of other possible ways for the assessment of the acceptability of biota exposure. It could be started possibly from the experience gained when handling severe contamination of the environment, typically after major radiation accidents, what have occurred. A series of findings and quantitative data were collected  after Chernobyl accident a and now after Fukushima. Though these scenarios cover only part of the problem, the results of their analysis could be also focused on how to extrapolate lessons from these for the more general application in the environmental protection . It would be more contributive  if the concept of environmental radiation protection would be specifically oriented to the really occurring situation, where an actual environmental problems could be expected. There were not presented (and it is also not referred to) any really existing situations where as a result of low doses some ecological loss appeared, or where really the biota were hurt,  and also what remedial measures might be adopted in such situations.  Another approach could be possibly based on continuing investigations in the regions with higher levels of radiation background, and it could be tried again to derive therefrom some values of benchmarks for the protection of biota.

It is then not surprising that in the text of the draft a notice appears at several places, that the issue of radiation protection of biota is still immature and deserves to be subject to further development. The risks should be considered what might result from the premature  introduction of the new principles of biota protection into the existing  system of radiation       protection. The inevitable financial costs of such a step and the increase of new commitments for regulatory authorities and operators should be kept in mind before a final version of this draft is adopted. 

The Czech Republic recommends to consider the postponement of the adoption and publication of the report. The time available should be utilized for detailed analysis of the feasibility to utilize some of another possible ways how to assess the acceptability of the exposure of biots besides the RAP models. This should include the review for this purpose the data about ecological consequences in Chernobyl area and the demonstration of the concievable harm to biota in other areas affected with contamination of radionuclides or experienced excessive levels of natural radiation background.