|DOE Office of Air, Water and Radiation Protection Policy and Guidance
Comments on “2005 Recommendations of the International Commission
on Radiological Protection (ICRP)”
Sections on “Protection of the Environment”
December 29, 2004
Background as Context for DOE Comments -
DOE comments provided are based on our experiences and lessons learned in developing and implementing methods and dose rate guidelines within a graded approach for evaluating radiation doses to non-human species, our development of the RESRAD-BIOTA code, participation in the ICRP Task Group on Protection of the Environment (ICRP Publication 91, 2003), participation in related IAEA Specialists’ Meetings and symposia on this topic, and our ongoing participation in the newly-formed Biota Working Group of the IAEA Environmental Modeling for Radiation Safety (EMRAS) initiative.
Summary Comments and Suggestions Regarding the ICRP 2005 Recommendations on Protection of the Environment:
Much of the material presented in the draft is not appropriate for a recommendations document because it lays out a plan of work rather than recommended actions. The presence of this material seems to imply a much greater degree of finality than would appear to be warranted. Several U.S. Federal Agencies have previously commented to ICRP on the topic of environmental protection. The concerns expressed in those comments remain valid. Given that the ICRP has stated that their activities have not been driven by any particular concern over environmental radiation standards, proceeding with the development of a framework parallel to the recommendations for human protection, including a complex, comprehensive biota research and dosimetry development program, appears somewhat premature. An assessment of where, under what exposure scenarios, and to what degree the current system of radiation protection for humans may not be protective of non human species may be warranted. A capability to compare and benchmark the results of the biota dosimetry methods and tools already developed and readily available through many countries would also be useful. From this assessment of current circumstances and capabilities, the potential need for and degree of complexity of future proposals can be better determined. The ultimate approach for protection should be flexible such that decision makers and users can select and use those dose evaluation and modeling tools that match to the specific purpose and data quality objectives of their assessment. .As stated in previous DOE comments, consideration should be given to a graded or tiered approach, including screening levels, to cost-effectively eliminate those situations which pose no harm.
The ICRP is encouraged to clarify its intent, and avoid detracting from on going efforts to improve, integrate, and harmonize the existing assessment tools and framework of protection of the public health and safety and the environment. The ICRP is also encouraged to engage in an ongoing dialogue on their proposals, and take the time necessary to develop an international consensus, since it is not obvious that there is a need for a framework for protection of non human species that parallels the current framework for protection of humans. Changes or additions to the radiation protection system for the public and the environment should produce benefits that are equal or greater than the costs of development and execution of such a system. This criterion should be a key factor in considering any new guidance for application to protection of non human species and should be integrated into any process for the development of such guidance.
1. We continue to believe, as expressed in earlier comments to ICRP in 2002 on this topic (December 13, 2002; RE: ICRP Draft Publication 91) that the ICRP’s decision to proceed with a complex, comprehensive biota research and dosimetry development program is somewhat premature. An ICRP-sponsored, resource-intensive comprehensive biota dosimetry development program is further questioned, given the suite of biota dose and risk assessment methods and tools currently under development or now widely available and implemented by many countries. A logical step in determining the nature, scope, and complexity of any ICRP-proposed protection system is to first review and assess the suite of biota dose evaluation methods and tools already developed and readily available through many countries, to include the U.S. (e.g., the Department of Energy’s Graded Approach for Biota Dose Evaluation and RESRAD-BIOTA code), Canada (e.g., methods to support the Canadian Nuclear Safety and Control Act), the United Kingdom (e.g., Impact Assessment of Ionising Radiation on Wildlife R&D Publication 128; 2001), and Sweden (e.g., the FASSET and ERICA Programs). From this assessment of current capabilities, the need for and degree of complexity of an ICRP-proposed system can then be determined. On this note we are pleased that the ICRP is cooperating with the IAEA’s EMRAS Program of methods and model comparisons regarding many of these available biota dose estimation approaches, and we are an active participant in the Biota Working Group through which these comparisons will be conducted.
2. Consistent with comment (1), an assessment of where, under what exposure scenarios, and to what degree the current system of radiation protection for man may not be protective of the environment should first be conducted. Such an assessment would provide insights on the degree of need for and appropriate complexity of a new ICRP dosimetry program for non-human species.
3. If a general framework for environmental radiation protection is advanced by the ICRP, we believe that an important component should be the inclusion of screening levels - levels of radioactivity or radiation dose that are clearly not harmful to non-human species under bounding conditions - within a graded or tiered assessment approach. Such a general screening level approach is common to many regulatory programs and can quickly and cost-effectively eliminate from further consideration those contaminants which pose no harm to the environment while allowing resources to be directed towards those contaminants having the potential to put non-human species at risk. As an example, DOE applies screening concentrations, termed “Biota Concentration Guides” or BCGs, in its graded approach for evaluating radiation doses to biota. Implementation experience using this approach since 2002 indicates that screening evaluations were successful in demonstrating biota protection, are cost- and time-effective, and in most cases eliminated the need for more detailed and resource-intensive dose and ecological risk assessments.
4. The ICRP development of a standardized set of reference organisms and related dosimetric models should carry a much lower priority of activity than the development of a revised policy statement, the development of a generalized protection framework, and development or re-affirmation of acceptable effects endpoints and dose rate guidelines for protecting populations of non-human species.
5. Care should be taken not to pattern the approach for biota protection solely for its ability to integrate with and be consistent with the ICRP’s proposed recommendations and approaches for human protection. There many be cases where such consistency and common level of complexity is either not appropriate, or where the protection system for non-human species - for technical, policy, and implementation reasons - should indeed be different than the ICRP’s approach for man.
6. As highlighted above, we believe that a number of dose modeling approaches for non-human species already exist. Rather than focusing on the development of comprehensive ICRP dosimetric models for biota, we believe that the ICRP’s first priority should be to develop high-level umbrella policy, and put forth a generalized framework and set of guiding principles (e.g., employing Data Quality Objectives considerations) through which currently existing biota dosimetry methods and tools can be selected and implemented. We believe that the second priority should be to provide recommendations on acceptable effects endpoints and dose rate guidelines (or acceptable ranges of guidelines) for protection of biota. Virtually all evaluation methods are based on the calculation of a dose to biota, which is then related to or compared with dose rate guidelines or a unit of measure/threshold (e.g., radionuclide concentrations in environmental media) that is determined to be protective of biota. Consensus-based effects levels and dose rate guidelines (whether for broad groupings of biota types, for individual taxa, or expressed in terms of environmental media concentrations) will be needed for the implementation of any framework that contains as an element the estimation of doses to biota.
7. The dose rate guidelines recommended by the NCRP (in 1991) and IAEA (in 1992) for protection of populations (using reproduction as the critical endpoint of concern) have generally been well received, validated, and implemented by a number of countries and organizations. As a starting point these dose rate guidelines, along with additional data available from recent studies (e.g., through the FASSET effects database) and from other countries (e.g., Canada through the CNSC efforts) could be re-evaluated. Up-front discussions and agreements regarding the data quality objectives for inclusion and interpretation of available data (and the planned approach to be taken, such as generation of No Observed Adverse Effects Levels, NOAELs) would need to be carefully and thoroughly discussed and agreed upon prior to this effort. Without the validation and/or re-affirmation of the currently applied NCRP and IAEA dose rate guidelines, or the development of consensus-based ancillary or alternative dose rate guidelines (or “benchmarks,” “consideration levels,” or some other acceptable terminology), risk assessors, regulators, and nuclear facility operators will be faced with many different and contradictory protection guidelines for biota that will complicate decision-making, particularly when working with stakeholders.
8. The ICRP Recommendations Document states in section 248, last sentence, “the question of whether one should protect individuals or populations from harmful effects of radiation in any particular circumstance is not an issue of direct concern to the Commission.” We suggest that this type of policy consideration is indeed an appropriate issue of direct concern to ICRP and its stakeholders, and one that ICRP should provide a position on. The standard and accepted practice regarding demonstrations of protection of the environment (i.e., non-human species) from stressors or agents (e.g., chemicals) is at the population level. As such, we believe that the development of acceptable dose rate guidelines (or environmental media concentrations corresponding to acceptable dose rates) should be based on population-relevant attributes (e.g., effects on reproduction; mortality; morbidity). They should not be based on effects that, while observed at the individual or sub-individual level (e.g., cytogenetic effects), have no relevance to protection of populations or cannot be quantified in terms of their impact to populations.
As an example of the difficulty and misapplication of effects observed at the sub-individual level, consider the point made by Dr. Norman Gentner, chairperson of UNSCEAR, at the NEA Forum in Sicily (February, 2002) and as quoted from his presentation abstract: “A special caution is urged if data on radiation-induced mutations per se are utilized as part of environmental assessments, as the average rate of radiation-induced mutation applicable in the context of environmental risk assessment is likely to be much lower than assumed from studies of induced mutation in non-essential genes, which is usually what is involved. Findings from the UNSCEAR 2001 Report (‘Heredity Effects of Radiation’) illustrate this point.”
9. This comment concerns the discussion on the ICRP’s proposed “Derived Consideration Levels” and proposed use of background concentrations. Given the wide range of uncertainty in our ability, based on the current state of science, to determine the relevance of impacts at the sub-individual level (e.g., cytogenetic effects) to effects on individuals, and the relevance of impacts on individuals (and their numbers impacted) to populations, along with the uncertainties associated with the presence of other environmental stressors, it is not clear how the proposed scheme would be implemented.