|The United Kingdom Ministry of Defence (MOD) has reviewed the ICRP proposals in the ICRP foundation document titled “The concept and use of reference animals and plants for the purposes of environmental protection” and has the following comments to make:
The environment around Chernobyl is now flourishing, primarily as a result of the absence of human intervention despite continuing high dose rates. Bio diversity now greatly exceeds the numbers before the 1986 accident. This would suggest that radiation even at the high levels found around Chernobyl is a lower order effect and that if we wish to protect endangered species and maintain a rich biodiversity, resources would be better expended looking at what changes are required to man’s activities e.g. overfishing, reducing the use of insecticides, etc. rather than expending them upon examining the effects of radiation to show that they are not affecting the reproduction of a species or depleting their population.
Radioactivity is but one of many pollutants that non-human species are being subject to and therefore it is questioned why a framework is being developed purely for radioactivity when it would be beneficial to consider the detrimental effects from all sources of pollution that non-human species are exposed to. In this way the most significant pollutants could be identified and the resources available can be directed to where the greatest benefit can be achieved.
The concept for reference plants and animals contained in this report is that a limited number of reference plants and animals should provide sufficient data to enable Derived Consideration Levels (DCLs) to be developed for other plants and animals using limited data and dosimetric models and environmental geometries to protect animals and plants from harmful effects specified in the report. However, it is unclear how this concept will be tested to determine whether the concept will deliver the desired outcome. Within the report there should be criteria developed and stated that can be used to test whether, or not, the concept works. For example, are there sufficient similarities between plant and animal species to use the reference plant and animal logarithmic bands of dose rates and endpoints and be able to apply this to other plants and animals? The achievement of the criteria, or not, should be a decision point as to whether to continue with, modify or cease to use the concept. Until such a point has been reached and practice clearly established, recommendations for non-human species should not be included in the main recommendations of the ICRP currently being produced. By delaying until the next round of ICRP recommendations (circa 2020) this would provide sufficient time to achieve a larger knowledge base and a better understanding of whether the ICRP view that the standards of environmental control needed to protect man to the degree currently thought desirable will ensure that other species are not put at risk is correct. This would be a measured and proportionate response to our current state of knowledge.
Because of the difficulties in extrapolating from high doses to low doses for man we have concerns that this may prove to be as much of a problem for developing risk models for plants and animals. Has any thought been given by ICRP how this will be tackled? If so this should be included in the publication.
Overall the document raises as many questions as it answers and many of these are contained in the specific comments that follow:
Page 8 paragraph 6 and page 14 paragraph 25 bullet 1. This states there are demands upon regulators to comply with the requirements of legislation directly aimed at the protection of wildlife and natural habitats. This statement needs to be expanded to explain what the radiation demands are, given the need for environmental impact assessments and harmonisation with chemical releases.
Page 8 paragraph 6. Is the use of different national approaches necessarily a bad thing as long as environmental protection is achieved? A statement is required to explain the benefits of international harmonisation.
Page 9 paragraph 8. The meaning of the sentence “And because radiation effects…………….developing an assessment framework” is unclear and the argument should be clarified.
Page 9 paragraph 8 last sentence and Page 13 pargraphs 21 and 22. The statement in the report that “The question of whether one should protect individuals or populations from the harmful effects of radiation in any particular circumstance, however, is not an issue of direct concern to the Commission” is questioned. It is difficult to see how ICRP can propose a framework for protection without addressing this issue of whether it is designed to protect individuals or populations.
Pages 9 and 10 section 2.2. The concept of DCLs expressed as concentrations of specific radionuclides does not appear to take account of the ability of a non-human species to uptake the radionuclide. Anthropogenic radionuclides may be released in different chemical forms resulting in a radioactive cocktail with the different forms having different pathways and different uptake coefficients in the same plant or animal. As this may have a significant effect on the potential dose it is difficult to see how the separation between natural and artificial is going to be achieved.
Page 10 paragraph 12. The suggestion that the reference animals and plants would serve as a primary point of comparison for other non-reference animals and plants so that more relevant information could be compiled for any other animal or plant that could be related in some way to the reference types is unclear. This would suggest that the reference plant or animal would not only be the reference plant or animal for its own species but for other species with similar lifecycles and exposure characteristics. This it is assumed to be ICRP’s working assumption. In doing such comparisons there may not only be similarities but also differences both between animals within the reference group and different species and it is unclear how such differences would be resolved to prevent each different species having to be its own reference animal or plant.
Page 13 paragraph 20 last sentence. It should be clarified whether natural background dose rates are referring to just external doserates, or does it include intakes of naturally occurring radionuclides.
Page 14 paragraph 25. An explanation should be provided as to why a separate framework for comparing detriment is required for radioactivity since consistency of approach can only be established by means of comparison with other sources of pollution.
Page 15 paragraph 28. The paper states that there is a need to be pragmatic about gaining information about radiation effects on types of wildlife that are subject to conservation measures etc. Although we can understand the reason for this it is unclear when the concept and models have been developed how it is possible to be sure that derived consideration levels will be applicable to what is considered to be this most critical groups of plants and animals. Some indication should be given how this issue will be addressed.
Page 17 paragraph 37. It is unclear as to why emphasis has been placed on vertebrate animals given the interdependency of species within ecosystems. If the aim is protection of the ecosystem, invertebrates may be of high importance from the assessment point of view.
Page 20 paragraph 44. Salmon and Trout are regarded as biological indicators of good water quality …..” Are there other reference animals and plants of similar significance in other environments, and hence of potential value? If so this would be worth stating in the reference plant or animal description.
Pages 22-26 Section 4.2 Within this section there should be some discussion concerning the source of errors likely to arise in such calculations.
Page 36 paragraph 103. This is repeated with some minor word changes in paragraph 105. It is suggested that one or other paragraph is deleted.