12 October 2012
Christopher Clement, CHP Email: email@example.com
International Commission on Radiological Protection (ICRP)
280 Slater Street, Ottawa
K1P 5S9 CANADA
Re: SENES’ Comments on the ICRP Draft Report: Protection of the Environment under Different Exposure Situations
We are pleased to submit SENES’ comments on the subject ICRP draft document.
Overall, the approach outlined in the draft document for the protection of the environment is presented in a concise manner that is relatively easy to understand. The approach should be helpful in providing broad guidance for the assessment of potential impacts on populations of non-human biota (NHB) arising from exposure to ionizing radiation. Among countries with modern environmental impact assessments, some have established comparable assessment approaches and others have not moved forward in this field of specialization. At present, only few countries seem to have incorporated the use of such approaches into their regulatory regimes. For obvious reasons, regulations tend to be more general and free from detailing a given approach. Given the complexity of this relatively new and still evolving area, there are still many opportunities for confusion and perhaps improper use of the approach and data. The ICRP’s document can perhaps provide a framework for broad discussion of such issues but regulations and regulatory control is a significantly different matter.
One apparent shortcoming is that the proposed protection approach lacks some of the components that are essential for regulatory purposes and for those who wish to implement the guidance. One example is the dual absence of limits (as upper bound values) for planned exposure situations and of the key notions of exclusion and exemption (as lower bound values). Moreover, the ambiguities around the notion of limits for planned exposure situations that the concepts of Derived Concentration Reference Levels (DCRL) and Environment Reference Levels (ERL) entail, has the potential to result in regulatory confusion and potential disharmony between countries in this emerging field of radiological protection of the environment. For example, it is difficult to imagine how DCRL - which ICRP considers equivalent to ‘Points of Reference for Environmental Exposure’- can replace the notion of limit in regulations. One reason that may explain the above two omissions is possibly that the proposed protection approach and its output are insufficiently mature for rigorous implementation as part of current regulatory regimes. The reality is that a notion of levels that would differ from limits – while being analogous to it – seems rather incompatible with current regulations, especially in the case of planned exposure situations or normal operations. Given this, the scope and intended applicability of the proposed protection approach may not be sufficiently clear at present.
Regarding the two sectors of (1) major nuclear installations as well as (2) of mining and milling of radioactive ores, it is unclear if there is a compelling case to substantiate a “blanket” inclusion of these two sectors under normal operations or planned exposure situations. In fact, very conservatively calculated exposure levels to NHB (at the individual level) that may approach DCRL could only be possible in rare exceptions: e.g., very localized environmental areas which may be subject to regularly higher radioactive releases and to high bioaccumulation phenomena. However, such exceptions significantly differ from the norm under normal operations or planned exposure situations. Considerable issues can also result from varying - and often very conservative - ways of calculating exposures of individual NHB (as opposed to populations of NHB) and then to directly comparing them to the DCRL. It is recognized that the proposed protection approach can be viewed as a useful tool to assess (and provide perspectives on) the potential impact from significant accidental radioactive releases into the environment – which are of relevance for emergency and existing exposure situations associated with the above-mentioned two sectors. However, it does not seem that extending the approach to planned exposure situations – irrespectively of the tiny exposure levels that characterize these two sectors under normal operations - is appropriate.
Overall, the proposed NHB approach is presented as simple and easy; however, it is not clear that the basic notion of NHB protection has been fully thought through in terms of regulatory application and efficiency. Moreover, the approach has a built-in tendency to address radiological protection of NHB in a detailed manner seemingly in isolation from the many other factors which regularly impact on the health of NHB. Finally, there is some potential for an imbalance at the practical level, for example, in managing effects which are small compared to the variability in natural populations arising from natural stressors such as climate change effects, variable water levels and the like which can result in large variations in local populations.
In complement, some more elaborated comments are provided in the Annex.
We thank ICRP for this opportunity to provide an input on the subject draft report. We look forward to the outcome of the current consultation process.
Yours very truly,
SENES Consultants Limited
Sylvain Saint-Pierre, P. Eng.
Vice-President, Marketing, Energy and Nuclear
c.c. Dr Douglas Chambers
SENES Comment on the ICRP Draft Report:
Protection of the Environment under Different Exposure Situations
The document translates the ICRP general approach of radiological protection (justification, dose limits/reference levels, and optimization) for humans, which applies to three different types of exposure situations (planned, emergency and existing), to the protection of the environment by introducing the notion of ‘Points of reference for environmental exposures’ or ‘Derived Consideration Reference Levels’ (DCRL). The DCRL are provided for each ‘Reference Animals and Plants’ (RAP), the RAPs being grouped according to their terrestrial, freshwater, or marine habitat (see Fig. 1). The document states (para.29) that ‘The Commission does not, however, recommend any generally applied form of dose limitation for biota.’ For planned exposures, Environmental Reference Levels (ERL) - for single source - which are more restrictive than the DCRL, are presumably added with a view to assure an adequate protection level for situations that involve multiple sources (see Fig. 2).
Main Comments: Regulatory Scope and Applicability
For regulatory purposes, it seems that the scope and applicability of the approach for the radiological protection of the environment is not sufficiently clear and that it would therefore likely pose significant difficulties for regulatory implementation. This key issue is amplified for planned exposure situations. This issue is detailed below.
This issue of NHB protection at the individual level should also be put in further perspectives for practical application. For example, let’s simply consider three fishes within 10 m from a discharge point for radioactive liquid effluents. What would it mean if the calculated exposure levels for only one of the three fishes is getting closer to the DCRL and that the exposure levels for the fish population further away from the discharge point are clearly much lower? Should such a situation de facto trigger a more in-depth assessment (tiered approach) and would this be efficient? What about if a fishmonger catches one of the three fishes? Clearly, although the proposed NHB approach is presented as simple and easy; it is not clear that the basic notion of NHB protection has been fully thought through in terms of regulatory application and efficiency. Moreover, the approach has a built-in tendency to address radiological protection of NHB in a detailed manner seemingly in isolation from the many other factors which regularly impact on the health of NHB.
The ICRP (at ll:176 – 189, ll:) discuss the use of DCRL and amongst other items, comment on cumulative effects. The ICRP suggest that the potential for multiple exposures can be considered through the use of “Environmental Reference Level (ERL), be established for a specific source at a level below the relevant DCRL”. Our experience suggests that the possibility of multiple exposures should be addressed specifically on a site by site basis rather than through arbitrarily set lower ERL. For existing exposure situations, the ICRP (at ll213-219) suggest that for existing exposure situations, that “if the dose rates are above the relevant DCRLbands, the Commission recommends that the level of ambition for optimization would be to reduce exposures to levels that are within the relevant DCRL bands, fully considering the radiological and non-radiological costs and benefits of so doing.” This seems intuitively reasonable; however, we are not convinced of the merit of spending much effort at optimizing below the lower boundary of the relevant DCRL band as suggested for planned exposure situations (e.g., ll 676, 677).
Comments on the End of the Report Conclusion:
 It is worth noting that the ICRP focus on dose-rate, which while important, is only one of the factors important in assessing the effects of ionizing radiation on NHB.