Protection of the Environment under Different Exposure Situations

12 October 2012

Christopher Clement, CHP                                                                 Email: sci.sec@icrp.org

Scientific Secretary

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

Dear Chris,

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[1]) 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

ANNEX

SENES Comment on the ICRP Draft Report:

Protection of the Environment under Different Exposure Situations

Brief Description

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.    

• Limits      (planned exposure situations) and/or DCRL-ERL:      Regarding the upper bound levels of the approach (DCRL), the reality is      that a notion of levels that would differ from limits – while be analogous      to it – is rather incompatible with current regulations, especially in the      case of planned exposure situations or normal operations. We noted that the definitions of DCRL (Glossary, lines 277-284) and of ERL      (Glossary, lines 295-300) include language that is analogous to limits. The      language used at the end of the conclusion (lines 935-938: “…one should stop…”) concerning DCRL is      also very similar to the notion of limits. At the international level,      such ambiguities around the notion of limits for planned exposure would      likely result in regulatory confusion and in significant disharmony      between countries in this emerging field of radiological protection.

• Limits      (emergency and existing exposure situations) and/or DCRL: The notion of DCRL – which differs from limits – may be less      problematic for these two types of exposure situations. However, it      remains to be seen if a priori      setting numerical DCRL at the international level is useful or not in case      of a major accident. For example, if after great effort post-emergency      levels would be a factor 10 or more higher than a DCRL, then what? The      on-going post-Fukushima experience is a case in point in terms of showing some      of the limitations of internationally recommended post-accidental levels for      human exposure (1 and 20 mSv/y).   

• ERL      (per sources): In principle, the introduction      of conservative margins with a view to maintain exposures lower than the      DCRL can be understood for planned exposures. A challenge that      is overlooked is that the normal focus of protection of NHB is on      populations whereas the effects data (e.g., DCRLs) are generally based on      effects to individuals. As noted by the ICRP, DCRL serve as “points of      reference” but need to be considered in the context of other factors      management objectives, the biota at risk and numbers of biota affected.      Our experience has been that such considerations will vary from situation      to situation and from regulator to regulator. Hence, applying the approach      at the individual level (para A.22) likely      introduces a considerable level of extra conservativeness on top of the      concept of DCRL and ERL. For example, even if a single NHB individual      would be exposed to a given level (at a given time and location) approaching      a DCRL, it would be very unlikely that this would cause a significant      effect at the population level of NHB. This issue would be even more valid      for levels that are approaching the ERL. There is a concern that by inherently      integrating a few layers of conservativeness, the approach may just become      unnecessarily restrictive for regulatory purposes at the lower end of      exposure levels.

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.

• Optimization      (planned exposure situations): In the same      line that what was just mentioned for ERL, imposing Optimisation at levels      that are lower than the ERL would most likely also be too restrictive (see      Fig. 3). The issue is not the applicability of Optimisation but rather the      fact that the range of application would be set at a too low level of      exposure, that it would be set too narrowly, and that it would most      probably overlap with the key notions of Exclusion and Exemption which      have been overlooked in the report (see the next item).

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).

• Exclusion/Exemption: At the start of Section 5 (Regulatory Framework and      Compliance, para. 40), the document refers to these two important “distinct concepts which delineate the      extent of radiological protection control” which are essential to the      efficiency of regulatory regimes. However, the concepts of Exclusion and      Exemption are virtually left unaddressed throughout the document. It is      therefore unclear if the proposed approach includes any lower bounds that      are necessary for regulatory efficiency. An approach that would consider that      any presence of radioactivity in the environment (regardless of the significance      of exposure levels) could not be efficient for regulatory purposes. By      analogy, for human protection, the level of 0.01 mSv/y (and even higher      doses) commonly relates to the notion of Exclusion and Exemption (e.g.      consider IAEA RS-G-1.7) (see Fig. 1).

• Major      Nuclear Installations, and Mining and Milling of Radioactive Ores (normal      operations): Under normal operations or      planned exposure situations, it is unclear if there is a compelling case      for a “blanket” inclusion of these two sectors. Considering current      experience, exposure levels that would approach DCRL are very unlikely in      these two sectors. 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      Approach for Planned Exposure Situation (planned exposure situations): Without clearer upper bound levels and lower bound levels, it      is hard to see how the approach can be fit for regulatory purposes.      Moreover, the combination of DCRL, ERL and optimization, suggests that the      margins between ERL and the notions of Exclusion/Exemption are probably      too small. If not better addressed, this issue may parallel the similar      problem of insufficient margins for protection of human exposure under      planned situations (e.g. 0.01 to about 0.1 or 1 mSv/y). Extending such a      problem to the RP of the environment is not desirable especially given      that the approach is currently under development. The ICRP affirmation      that “the protection of the      environment from a source should complement controls to protect the public      and not add unnecessarily to its complexity” does not seem supported.      The same applies for the affirmation which states that “the demonstration of protection of both      humans and non-human species as a result of planned (normal) exposure      situations might well in the future be integrated in a relatively simple      way”.

Comments on the End of the Report Conclusion:           

• The last      paragraph (para. 57) of the Conclusion is puzzling (“…the present state of knowledge, and of ignorance,…”). It may      be that the source of the problem derives from text editing, but as it is,      the text tends to give an impression that the report’s authors are extremely      knowledgeable in DCRL whereas everybody else aren’t, thus suggesting to      apply the DCRL in the way indicated in the document. However, as shown      earlier, it does not seem that the approach laid out is appropriate for      regulatory purposes. May be a part of the problem is related to some      misunderstanding between the scope of regulatory matters and the one of an      assessment tool. 

[1] 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.