Protection of the Environment under Different Exposure Situations

Draft document: Protection of the Environment under Different Exposure Situations
Submitted by Graham Smith and Karen Smith, BIOPROTA Technical Secretariat
Commenting as an individual

The following observations are made from the perspective of solid radioactive waste disposal. They are provided by Graham Smith and Karen Smith, BIOPROTA Technical Secretariat, an international collaborative forum designed to support resolution of key issues in biosphere aspects of assessments of the long-term impact of contaminant releases associated with radioactive waste management, see

The observations do not represent the opinions of member organisations of BIOPROTA, nor do they represent a consensus developed by them. They are made by the Technical Secretariat, taking into account a range of technical work produced without and beyond BIOPROTA activities.

  • The document is intended to apply to different Exposure Situations, and that explicitly includes waste disposal.
  • In relation to solid radioactive waste disposal and protection of humans, ICRP 81 recognises the additional uncertainties in assessment of exposures arising in the very long term. Thus, ICRP 101 recommends generally, assessment of exposures of adults children and infants, but in relation to solid waste disposal and possible releases from repositories in the far future, consideration only of adults was suggested (ICRP 81). The curret document could usefully recognise that there can be additional uncertainties concerning the ecosystems and their make up at a particular site in the far future, as has already been noted in the draft update of ICRP 81.

    2. Data gaps

    The ICRP may like to note that consideration has been given to protection of the environment and releases from solid waste disposal facilities, both in terms of data quality and compliance with protection objectives in the following references which have received wide input and review from the international community.

    • Smith K, Robinson C, Jackson D, De Laz Cruz I, Zinger I and Avila R (2010). Non-human Biota Dose Assessment: Sensitivity Analysis and Knowledge Quality Assessment (September 2010). Report prepared under the BIOPROTA international programme. Published as Posiva Working Report 2010-69 by Posiva, Olkiluoto, Finland.
    • Smith K, Jackson D and Wood M D (2012). Demonstrating Compliance with Protection Objectives for Non-Human Biota within Post-closure Safety Cases for Radioactive Waste Repositories. Report prepared under the BIOPROTA international collaboration programme.


    3. The stated protection objective is prevention or reduction of “the frequency of deleterious radiation effects to a level where they would have a negligible impact on the maintenance of biological diversity, the conservation of species, or the health and status of natural habitats, communities and ecosystems”.

    The objective of negligible impact appears to offer a higher level of protection than that provided by the system of protection humans. For humans, by comparison, the level of protection afforded is high, but dose limits and constraints are not set at the level of negligible risk. This difference may appear to introduce bias towards protection of the environment in the proposed environmental protection system.

    4. The DCRLs are defined as, ‘A band of dose rate within which there is likely to be some chance of deleterious effects of ionising radiation occurring to individuals of that type of reference animal or plant.”.

    There appears to be a substantial disconnect between the stated protection objective (protection at the, species, diversity, habitat and system level) and the quantity used to indicate compliance with that objective (which is individual protection based). For practical purposes this may be necessary at this stage.  It may be useful to recognise this, and to indicate that further work is needed to provide more definitive indicators at the eco-system level, to more directly address the protection objectives and explain the relationship between likely to be some chance of deleterious effects at the individual level, and negligible impact on the maintenance of biological diversity, etc.

    In addition, it may be useful to provide advice about the spatial and temporal averaging which would be appropriate in determining environmental concentrations of radionuclides used in assessing the dose rates for comparison with DCRLs. In particular, if protection is intended at the system (etc.) level, then advice on the how to do the concentration calculation relevant to the impact on a population of individual biota corresponding to the protection of the system would be helpful.

    5. The Commission recommends at line 671 that “DCRLs be used under all circumstances where there is an environmental exposure of significance from any major nuclear facility in order to assist, further inform, and to guide efforts to optimize protection of the environment.”

    The DCRLs are an indicator of significance of exposures, or at least a point of reference for them, so to use them in the case where the exposure is significant is circular. In the case of planning  future releases etc., the exposure is not yet extant. It may therefore be useful to say ‘where there is cause for concern over potential environmental exposure of significance’.


    6. The document is clear that the DCRLs should not be considered or used as limits as indicated at line 935, “These bands, 935 or DCRLs, have therefore been identified as being rates of dose within which, if experienced or expected, one should stop and consider further what best to do”.  Continuing, the Commission, line 939, “believes that, given the present state of knowledge, and of ignorance, it would be prudent to use the DCRLs in the way indicated in this document for different exposure situations.”

    The emphasis on ignorance (see also the reference to lack of data at line 834) appears both inappropriate and wrong given the extensive background of research carried out, both historically and in recent years. It might be appropriate to indicate the need for further work (as indicated above in relation to system level understanding) but not to invite the inference that the basis for the current recommendations is weak. This could to lead to the (unintended and inappropriate) use of the lower end of the DCRL and ERL bands as limits, as being the only possible conclusion to the question, what best to do.