Comment on Draft 2005 ICRP Recommendations
After a number of years of only seeking comment from the scientific community or industrial sector Greenpeace welcomes the ICRP opening its discussion on the Draft 2005 Recommendations to public comment.
Greenpeace would also like to be note that the following comments on the Draft 2005 Recommendations of the ICRP on general radiological protection have been prepared before publication of a number of the key ICRP foundation documents that were supposed to accompany the draft. It is understood that the delay has been due to a lack of agreement within the Commission on the wording of these documents. The following comments are made with this in mind.
The present ICRP Recommendations on radiological protection standards were published in 1990 in ICRP Report 60. Proposals for a new set of ICRP recommendations to replace ICRP 60 have been made since 1999 (Clarke, 1999).
If adopted, the Draft 2005 Recommendations will lead to a lowering of radiation protections standards for the public and workers.
Potential for public exposure to increase under the draft
The ICRP recommendations, as they stand, propose a recommended 1 milliSievert (mSv) dose ‘limit’ from all sources with a lower ‘constraint’ level of 0.3mSv from a single source - this takes into account the possibility that people may be exposed to several different sources.
The main changes in the Draft from the ICRP’s 1990 recommendations is that it will scrap the recommendation of the lower constraint limit – leaving it up to national regulators to decide if they want to continue to use it. To further add complication, a new constraint of 1 mSv is proposed but 1 mSv also remains as the dose limit. A number of commentators on the ICRP’s 2005 Recommendations have commented that this creates confusion.
It is understood the Commission’s initial proposal contained a reference to a lower constraint of 0.3 mSv, which the ICRP at one time had sought to impose it as the “normal activity” dose constraint, until protests from industry and other quarters led it to raise that number to 1 mSv.(Note: see International community embraces draft of 2005 ICRP recommendations Nucleonics Week /Volume 45 / Issue 23/ June 3, 2004. See also ICRP chairman drops lower dose constraint, Nucleonics week June 19th 2003). The Commission’s decision to press ahead with a 1mSv ‘constraint’ is worrying as this represents the maximum level of risk for an individual from radiation exposure – in fact this is exactly why constraints were put in place to prevent people being exposed to the maximum level.
The ICRP’s Draft contradicts moves by national bodies such as the UK’s Health and Safety Executive which propose, as a Basic Safety Objective, a dose of 0.02mSv from greenfield sites (new facilities). The ICRP recommendations could see newer plants been built with lower design standards. The ICRP Draft also ignores criticism of its 1990 recommendations when its own evidence showed that dose limits should be reduced to at least 0.2mSv (see NRPB (1987) ‘Interim Guidance on the Implications of Recent Revisions of Risk Estimates and ICRP 1987 Como Statement’, NRPB-M238. See also ‘Permitting Unacceptable Risks’ Dr Pad Green (whose doctorate was on the ICRP) for Friends of the Earth London).
Potential for worker exposure to be increased?
For workers the concept of a ‘constraint’ limit of 15mSv, as used in the UK, in any one year has also been ignored in favour of a proposed 20mSv ‘constraint.’
Potential for massive doses in the event of emergencies to workers and the public.
For emergencies the ICRP will recommend an upper dose constraint level where “action is needed” of 100 mSv per year e.g. emergency workers, evacuation or relocation in emergencies.
There is also provision in the draft that a ‘constraint’ of 20 mSv/yr would apply to members of the public for actions of sheltering or administration of stable iodine after accidents, to “existing exposures” such as from radon in homes or public areas, and to “comforters and carers” for radiotherapy patients.
Background radiation used to ‘justify’ exposures from man-made sources
It is extremely worrying that the Commission is attempting to use naturally occurring radiation exposure as a measure against which exposures from man-made sources can be justified. The Commission fails to acknowledge that man-made exposures are an additional avoidable exposure to an existing unavoidable exposure (from natural sources). The attempt to set man-made exposure next to natural exposure is remarkably similar to the nuclear industry’s continued use of natural exposure to put man-made exposure into ‘perspective’ and thus excuse its own shortcomings.
The ICRP ignores the fact that man-made exposures are in addition to whatever exposure a person receives from natural background. Using a natural exposure limit of 1mSv to ‘justify’ a man-made exposure of 1mSv could, for example, result in an individual’s radiation exposure increasing by 100% in a year. Even for an exposure of 2mSv per annum from natural sources, a 1mSv dose from man-made sources would be a 50% increase over dose. The ICRP singularly fails to acknowledge the risks from the combined sources of radiation exposure.
In addition to ssignificantly weakening or questioning existing dose limits; suggesting that background radiation be used as a benchmark for risks and man-made exposures the draft also:
a. undermines the existing established system of radiological protection
b. ignores new information on novel radiation effects
c. ignores studies on uncertainties in dose estimations
d. introduces lax exemption limits, and
e. introduces lax radon action levels
Media reports show that most of the changes have come about due to pressure from the nuclear industry. It is worrying that after years of progressive reductions in permitted radiation exposures from the nuclear industry that radiation exposure limits might be increased – based not on scientific evidence but on industry lobbying and claims that the system needs to be made more ‘simple.’ Overall, the draft seems to be more concerned with protecting the interests of those responsible for the activities giving rise to radiation exposures rather than the interests of those who are exposed.
Examination of the ICRP’s documents leads to no other conclusion that the Draft 2005 ICRP Recommendations are unfit for further examination and should be withdrawn.
1. Criticism of the ICRP’s draft recommendations from the scientific community
Since the draft recommendations were published they have attracted an unprecedented level of controversy and widespread opposition. A partial list of the objections may be seen in the following publications or proceedings:-
•Schrader-Frechette and Persson (2001)
•UK National Radiological Protection Board (see ICRP website 2004)
•Proceedings of the EC Stakeholders' Conference on environmental radioactivity, December 2002, in Luxembourg, see http://europa.eu.int/comm/energy/nuclear/radioprotection/doc/conference/shc_2003_09_19_proceedings_en.pdf
•the comments from independent scientists posted on the ICRP’s own website http://www.icrp.org/remissvar/listcomments.asp
•the rejection of provisions in the ICRP draft by the IAEA’s Safety Standard Series Guidance on Exclusion, Exemption and Clearance levels (published in August 2004 after the final ICRP draft had been published)
•the comments of the UK National Dose Assessment Working Group (now on the ICRP website) http://www.icrp.org/remissvar/listcomments.asp)
•The EC’s Article 31 Group of Experts meeting on the ICRP proposals in Luxembourg in November 2004. This is understood to have criticised many proposals in the draft, and recommended further time for the draft’s consideration or its complete revision.
Although a scientific commentary normally would eschew comments on matters concerning individuals, this is unfortunately unavoidable in the present context. The present ICRP draft has been suggested, drafted and promoted primarily by one person, Dr Roger Clarke - the ICRP Chairman, without visible signs of support from within the ICRP. Indeed, one nuclear industry representative at the UK Ionising Radiation Health and Safety Forum (London November 2004) stated the push to change the recommendations were “very much a personal crusade” for Dr. Clarke.
Given that the actions of Dr Clarke have not met with consensus support from the scientific community or even from within the ICRP itself, it is questionable whether these proposals should be being considered at all.
2. Lack of Clarity
A comment made by many objectors or neutral commentators to the 2005 draft is that it is exceedingly unclear about exactly what measures it is proposing, how these differ from the existing 1990 Recommendations, and why the changes are being proposed. The draft’s intentions only partially emerge after reading and re-reading various sections, usually in conjunction with later or earlier sections. Even then, the reader is never quite sure about the real aims of the draft, as these are not set out clearly. What seems apparent is that the current draft is the end product of many redrafts, revisions and additions of texts which do not meld well with each other.
3. Regressive Proposals
Nevertheless, enough is discernable to conclude that the general tenor of the draft is profoundly regressive. Most important, the draft singularly fails to support the current ICRP principles of justification, optimisation and limitation. On justification, paragraph 18 for example states that this is largely outside the scope of the Recommendations, but it does not explain why this is the case. On optimisation, the draft appears to relegate this so that it is used only after the constraints are applied. On limitation, the current ‘limits’ still apply but these are weakened by also designating them as ‘constraints’, without explanation of how the two will be applied together All exposure to radiation must produce “a positive net benefit”. This is the JUSTIFICATION principle. (These are:
All exposure must be kept “as low as reasonably achievable”. This is the ALARA principle.
All exposures should not exceed the DOSE LIMITS set by the Commission. Since 1977, the ICRP’s dose limits have been set at 50 mSv ICRP (1977) ‘Recommendations of the International Commission on Radiological Protection,’ Annals of the ICRP 1 No 3 for workers and since 1985 1 mSv for members of the pubic ICRP (1985) ‘Statement of the 1985 Paris Meeting of the International Commission on Radiological Protection)
Greenpeace believes that – at the very least - the limits as currently set must remain as absolute limits not to be exceeded. Constraints – at lower much dose rates than the limits – should be recommended in order to avoid exposure near to the limits as the limits represent the maximum risk acceptable.
This weakening of the current system and the limits it contains is unfortunate as the system and its underlying principles are understood and accepted by all stakeholders in radiation protection. The draft seems to suggest that these principles should replaced by an incoherent set of source constraints which are unclear, variable, and largely dependent on the circumstances of the source and the exposure.
The Draft contains other regressive proposals. These include
•the implied downgrading of collective dose, via the sidelining of optimisation
•the proposal for the action level for domestic radon levels to be increased to 600 Bq per m3
•the unnecessary introduction of the concept of exclusion levels, below which material is effectively treated as non radioactive and completely excluded from any regulatory oversight
•the extremely lax levels of such proposed exemption levels (eg 100 Bq/kg for beta/gammas), some of which are more lax than values used for nuclides in the current Codex Alimentarius and for CFILs
•the continued use of a radiation weighting factor of 1 for low-range beta emitters and Auger emitters
No coherent, clear justification is given for any of these proposed changes. For these reasons, the draft should be withdrawn. The current ICRP provisions (although somewhat out-of-date) continue to provide greater protection, clarity and guidance than the 2005 draft.
4. No recognition of new information since 1990
Since the 1990 ICRP Recommendations, a very large body of new information and research findings has emerged on the health effects of ionising radiation e.g. since the ICRP draft was published in July 2004, a number of reports have been published including the CERRIE report (2004) and the 9th COMARE report (2004). However the 2005 draft barely mentions, far less discusses, this new information. Most importantly, this new information includes a range of ‘novel’ effects of radiation, ie bystander effects, genomic instability, and minisatellite mutations. These may have serious implications for current understanding of radiation effects and risks, but they are completely ignored in the 2005 draft. Other matters which are not considered, or are dismissed in a sentence or two, include the need to consider uncertainties in both dose estimates and risk estimates.
Specific comments on sections of the ICRP Draft
1. Background Radiation
Perhaps the most important new proposal in the draft 2005 Recommendations is the suggestion that the current yardstick for the acceptability of radiation exposures should be changed. However this suggestion can only be gleaned from a close textual analysis and comparison of various paragraphs dotted about the draft. Some of these statements are difficult to understand. For example, paragraph 157 states “The existence of the natural background of radiation does not provide any justification for additional exposures, but it can be a benchmark for judgment about their relative importance and the need for action.” This sentence does not make sense. If added exposures cannot be justified by background radiation, then how can it be a benchmark for judgments? Clearly, differing views within the ICRP have not been reconciled here.
Currently, the yardstick is (or is supposed to be) the average annual risk of fatal cancer to an individual: this should lie between 1 in 100,000 and 1 in 1,000,000. In fact, this level of risk has already been undermined in recent years. For example, the current 1 mSv annual dose limit for a member of the public translates to a fatal cancer risk of 5 per 100,000, i.e. 5 times higher than it should be.
The 2005 draft proposes to eliminate this altogether and to replace it with comparisons with average annual external background radiation levels of about 1 mSv per year. The draft suggests that the public finds these levels understandable and/or acceptable so they should be used as a yardstick for levels of acceptable risk from additional sources of radiation. This facile and unsubstantiated reasoning is worrying. It should be rejected for a number of reasons
a. it conflates public attitudes to background radiation and to man-made radiation. The public may accept the inevitability of background radiation, but it does not view additional man-made exposures in the same way. Indeed public surveys indicate great concern about industrial practices resulting in radioactive discharges to sea and air.
b. it ignores the fact that man-made exposures are in addition to whatever exposure a person receives from natural background. Using a natural exposure limit of 1mSv to ‘justify’ a man-made exposure of 1mSv could see an individual’s radiation exposure increase by 100% in a year. Even for an exposure of 2mSv per annum from natural sources, a 1mSv dose from man-made sources would be a 50% increase over dose. The ICRP singularly fails to recognise the risks from the combined sources of radiation exposure, attempting instead to use one source to justify another.
c. it overlooks the key point that anthropogenic releases are subject to decision by social and political processes whereas external background radiation is not
d. it invites the inference that background radiation may be viewed with equanimity, which is incorrect. For example, the NRPB has estimated that background radiation will result in about 6,000 to 7,000 future UK cancer deaths per year (Robb, 1994).
e. it assumes that the public is well-informed about the risks of background radiation, when the opposite is the case. Few members of the public are aware of the above Robb paper for example
f. many scientists have stated that comparisons between man-made radiation exposures and background radiation are inappropriate (see comments by former ICRP Commissioner Lindell (1989), by the nuclear industry (NRPB 1990), by the NRPB (Webb et al, 1983) and in European Commission documents, for example chapter 8.3.4 in Bush et al (1984)).
g. Notably, comparisons with background exposures are not used to justify the acceptability of industrial discharges of chemicals which are also naturally occurring, e.g. carbon monoxide, ozone, oxygen, dioxins or furans
h. Finally, the current ICRP system of radiation protection of limitation, optimisation and justification (ICRP, 1991) omits any reference to comparisons with natural background radiation as a criterion of radiological acceptance. It is understood this was a matter of deliberate policy.
Perhaps the most disappointing aspect of the ICRP’s proposal to use background radiation as a benchmark is its reliance on the public’s haziness about the facts of background radiation. Indeed, background radiation is dangerous for a number of reasons. Radiation is intimately connected with ageing, and is part of the reason why we are not immortal. That is, annual background radiation doses accumulate over the years and gradually weaken the body’s defence mechanisms leaving us open to death from opportunistic infections and diseases. Background exposure also causes neoplastic mutations in autosomal cells which may result in fatal cancers, especially as we get older. As stated above, background radiation is estimated by the NRPB to be the cause of 4% to 5% of all cancer deaths each year in the UK. For example, Dr Baverstock (2003) has claimed that all childhood leukaemias are in fact are caused by background radiation. In addition, a significant factor as to why older women who become pregnant have stillbirths or produce offspring with high rates of congenital abnormalities is that the ‘stock’ of egg cells in their womb has been subjected to background radiation for longer, which causes deleterious mutations in their egg cells.
The ICRP should not advocate using natural background radiation as a justification for radiation exposure from man-made sources.
2. Wrong objective
The draft states that “The primary aim of radiological protection is to provide an appropriate standard of protection for man (sic) without unduly limiting the beneficial actions giving rise to radiation exposure.” This is an uninspired and uninspiring aim, more suited to a commerce group or manufacturer’s association than to a body which calls itself the International Commission on Radiological Protection. It appears the Commission is more concerned with not ‘unduly limiting’ activities which give rise to the (assumed) beneficial effects of radiation exposure (regardless of the source) than providing protection.
This aim notably omits reference to health or well being in its text. It does not define what it means by an “appropriate” standard of protection. Appropriate to whom, for example? And why no reference to the environment and other forms of life? Nor does it explain what is meant by ‘unduly limiting’ and who this concept has been produced to benefit – public and workers or the nuclear industry?
A better aim would be…. “to provide advice and assistance to national radiation authorities and others on the latest scientific information and understandings about the health impacts of radiation on humans and all forms of life, in order that they make suitable provisions (including legislation, policy and regulatory advice) to maximize protection of the health and well being of individuals and populations from radiation exposure.”
3. Confusion between Constraints and Limits
The ICRP Draft (page 43) proposes a series of constraints which would, somehow or other, co-exist with current limits. The proposed constraints (no longer limits) are as follows
• For workers, in emergencies but other than for saving life or preventing serious injury or preventing catastrophic circumstances (under which situation there may be not limit), the ‘constraint’ is a 100 mSv effective dose , either acute or in a year, as the maximum value to be received. 100 mSv is also the maximum ‘constraint’ set by the Commission to restrict exposure of individual members of the public following an accident.
While there may, unfortunately, be circumstances in which workers (site personnel or emergency services personnel) are exposed to levels up to 100mSv, there is no detailed explanation of how this can be justified or what measures should be taken to avoid any further exposure for these individuals in their future work. As for members of the public, a 100mSv dose exceeds an average ‘permitted’ lifetime exposure of 75mSv (assuming an average life of 75 years). Recommendation of such a high level of exposure turns previous thinking on these issues on their head. It could lead some operators (and regulators) to believe that if, in the event of a major release, they could abdicate their responsibility to avoid or lessen exposure to the public. This is in effect a ‘Chernobyl clause’ and should be withdrawn.
• The maximum value of 20 mSv/year effective dose is recommended for selecting constraints in situations where there is a direct or indirect benefit for the exposed individuals. It would be used in normal situations for occupational exposure.
There is no mention of a 15mSv constraint level for workers as practiced in the UK, even though unions and regulators welcomed this constraint (recommended by the NRPB) as useful in driving down average dose rates in industries where radioactive materials are handled.
• The maximum effective dose of 1 mSv/year is recommended to select constraints in situations where there is no direct benefit for the exposed individuals.
Whilst 1mSv would be the maximum public ‘constraint’ in normal situations while in case of multiple dominant sources a figure of 0.3 mSv/year would be more appropriate (as stated in ICRP Publication 77) and 1mSv left as a maximum.
Why is the change being made from a constraint of 0.3mSv to a ‘constraint’ of 1mSv? Is this because, as media reports suggest, that the nuclear industry is winning in its lobbying of the Commission? (ICRP chairman drops lower dose constraint, Nucleonics week June 19th 2003).
This is not the first time the ICRP has given into industry lobbying. In 1990, using new evidence from studies of Hiroshima and Nagasaki, the ICRP should have lowered the permitted dose to 0.2mSv. Then, as now, it looks like if the ICRP is caving in to pressure from the nuclear industry and proposing to increase doses rather than follow the scientific evidence and decrease them.
A further problem is that these constraints blur into one another leaving no effective guide for what is acceptable or is not acceptable. For example, paragraph 160 states “Individual doses of several tens of millisieverts, whether they are received either singly or repeatedly, require that action be considered.” This is of little help either to RP practitioners or to the exposed public, and represents an apparently deliberate weakening of the current limits. For example, at present in the UK, criminal sanctions apply if the public dose limit of 1 mSv per year is exceeded. The ICRP draft states that where exposures to “several tens of millisieverts” occur then all that would be necessary is that “action be considered”; that is action does not have to be taken, only considered. This is unacceptable. Although pparagraph 185 states that constraints under normal conditions will be more restrictive than limits, this is contradicted by the rest of the draft.
The ICRP notes that in ‘practical protection, it is useful to introduce further constraints to deal with all situations in more detail.’ By not detailing those other constraints the ICRP is totally neglectful of its role and responsibility as an international advisory body on such issues. Why should national regulators impose stricter conditions on working conditions, accident situations or exposures from routine activities if the ICRP is not prepared to recommend them? If the ICRP expects respect for its opinions and action taken on its proposals then it should be clearer and more stringent in its own proposals.
These ICRP proposals on constraints should be withdrawn. Dose limits for workers should be set at 12.5mSv and 0.2mSv for the public (with lower constraints were possible) in line with the evidence the ICRP had in 1990. The current Draft is regressive and gives no explanation as to why radiation dose constraints should be relaxed.
4. Ban on Retrospective Assessments
Paragraph 54 states “…. effective dose is intended for use as a principal protection quantity for establishment of prospective radiation protection guidance. It should not be used to assess risks of stochastic effects in retrospective situations for exposures in identified individuals, nor should it be used in epidemiological evaluations of human exposure…”
This paragraph appears to exclude the retrospective application of effective dose estimation. However, this exclusion is unrealistic as in order to demonstrate compliance with dose constraints and to estimate doses to individuals for record-keeping purposes, it will be necessary to carry out retrospective calculations.
These ICRP restrictions on retrospective dose assessments should be reconsidered or withdrawn.
Major uncertainties exist in current estimates of internal radiation exposures. The CERRIE Report considered uncertainties in dose estimates at considerable length (CERRIE Report, section 2.7, Uncertainties: para. 51-65) reaching the conclusion that assessment of uncertainties in dose and risk estimates should be an important component of the dose estimation process ( CERRIE Report, Chapter 5: Conclusions, para. 8). Only in cases where prospective calculations suggested that doses were "well below" regulatory dose constraints (or limits) would omission of specific consideration of uncertainties be justified (Note: As with the ICRP's related statements, the warning is still in essence paradoxical). The Committee concluded that serious uncertainties may arise at all stages in the dose assessment process, and that overall uncertainty in estimates of effective dose would almost always cover a wide range, encompassed by a multiplying factor of 2-3 both above and below the estimated central value of dose (Note: In the CERRIE Report, the range limits referred to were the 5th and 95 percentiles of a hypothetical log-normal distribution). In some cases, this factor might be up to or exceed an order of magnitude, again in either direction.
The draft ICRP proposals, on the other hand, almost ignore the issue of uncertainty in dose estimates. The Commission attempts to rationalise this attitude at the end of its Dosimetry Foundation Document. (Foundation Document, ICRP Committee 2: Basis for Dosimetric Quantities used in Radiological Protection (Dietze et al.), Draft for Discussion, 22 August, 2004 (ICRP/22/42/04). Chapter 6 "Uncertainties and Judgements in Radiological Protection"), where it asserts that it
"takes the position that the dosimetric models as well as the parameter values that the Commission recommends for determining doses from quantitative information about radiation fields in the environment or from intakes of radionuclides are not subject to uncertainty." Foundation Document, ICRP Committee 2: p.36, third paragraph. (emphasis added)
This reinforces a statement earlier in the same document where, with reference to radiation weighting factors, it states that
"values of wR are fixed by convention and by definition they are not associated with any uncertainty." Foundation Document, ICRP Committee 2: last sentence on p.19. (emphasis added)
The apparent disparity in attitude between CERRIE and ICRP appears to arise, at least in part, because ICRP consider it is discussing only prospective assessments, for "planning and assessing normal occupational exposures, planning for discharges into the environment and for generic assessment of doses". Foundation Document, ICRP Committee 2: fourth paragraph.
CERRIE, in contrast, attempted to determine what level of risk attached to real people, and is therefore concerned to include retrospective doses and the associated uncertainties in their evaluation. By restricting assessment of effective dose entirely to prospective evaluation, by using formal models and reference individuals and by defining values of parameters and weighting factors, ICRP claim to dispose of issues relating to uncertainty. This is done by stating that uncertainties in the defined quantities are held to be non-existent. Whilst it is certainly possible to claim that a definition is not subject to error, it does not follow that dose estimates made using that definition are free of uncertainty.
The ICRP’s attitude is unrealistic, for the following reasons.
• whilst specific values of parameters and weighting factors for models may ultimately need to be selected, it is wrong to claim there is no error associated with them.
• while it is, in theory, possible to define a formal process for prospective evaluation in which no uncertainty exists or is minimised, the tests of such an evaluation will necessarily be retrospective, and based on observational quantities and the habits and physiologies of real people. If ICRP is to achieve its stated aim "to provide an appropriate standard of radiological protection for man", then the ability to compare the formal prediction (on which the regulations to control the outcome would have been based) with the actual dose (viewed retrospectively) is an obvious necessity.
• to limit in practice the ICRP recommended methodology to prospective assessment would defeat the objective of radiological protection. For example, how could dose records for individuals have any credibility unless based on actual data relating to the individual concerned? How could public stakeholders have any confidence in the safety of an industrial operation in the absence of retrospective demonstration of exposures (say to critical groups)?
It is recommended that the ICRP read the recent CERRIE report and reconsider its draft proposals in light of what CERRIE and other have to say on this issue.
Paragraph 180 states that the upper levels of 600 Bq/m3 for radon in homes and 1500 Bq/m3 for radon in workplaces are seen as maximum constraints, which the Commission regards as providing the basic level of protection. The proposed domestic level is much higher than the action level recognised in the UK which is 200 Bq /m3 for radon in homes. It is also unconservative in the light of a number of forthcoming major epidemiological studies. These include the American pooling study (Krewski et al. in press) and the German pooling study (Wichmann et al. in press) which show an elevated Relative Risk of about 1.10 per 100 Bq/m³ (1.40 for radon concentrations above 140 Bq/m³). A Europe-wide pooling study is also completed (Darby, Krewski et al., submitted) with similar findings.
A public explanation by the ICRP Secretariat reveals just how unsafe the proposed constraint for radon levels in home is. In a response to the web submission by H Erich Wichmann (see www.icrp.org), the Secretariat states “The figure of 600 Bq/m³ is the value where ICRP considers that remedial action is certainly warranted. We expect national authorities to optimise the level of protection to be achieved - which has to be a national process, taking account of the costs and number of dwellings involved.”
This reply avoids the reality that, in most countries, the current action level where remedial activity is necessary is already much stricter than 600 Bq/m³. It also begs the question why is the ICRP giving out advice saying in effect to national authorities ‘you can lower your radon standards’. The ICRP will fail in its stated aim of radiation protection if it allows this to go ahead.
The Commission should withdraw these proposals on radon and consider the above new findings, new reports, and new studies on uncertainty, before bringing in a new draft.
7. Exclusion levels
The ICRP has introduced the concept of exclusion levels for the first time (see table S2, ICRP Draft). This has caused much adverse comment in regulatory circles. No justification is given for the introduction of this section. The ICRP is proposing that, below these concentrations, materials would not be considered radioactive at all, i.e. they would be excluded “completely” from ICRP Recommendations. If followed this would mean such materials would be outside any regulatory control whatsoever for all time. Not surprisingly this has attracted the disapprobation of regulators as it would remove such material from their overview and from public scrutiny.
Table S2. ICRP Proposed Exclusion Levels
Nuclides Exclusion activity concentration Bq/kg
Artificial a –emitters 10
Artificial / emitters 100
Head of chain activity level, 238 U, 232 Th 1,000
40 K 10,000
† For 238 U and 232 Th chains, this value also applies to any nuclide in a chain that is not in secular equilibrium, excluding 222 Rn and daughters in air which in all situations are controlled separately.
Exclusion is to be distinguished from exemption. Exemption levels apply to practices allowing them to continue without day to day regulation, but so that they may be brought back under regulation later, if needs be, in the view of the regulator. That is, it is a form of generic authorisation. It is greatly to be preferred to exclusion.
Advice on exclusion was originally contained in the IAEA’s Basic Safety Standards (BSS). The BSS stated that “Any exposure whose magnitude or likelihood is essentially unamenable to control through the requirements of the Standards is deemed to be excluded from the Standards” (Ref. , para. 1.4). Examples of excluded exposure given in the BSS are: “exposure from 40K in the body, from cosmic radiation at the surface of the earth and from unmodified concentrations of radionuclides in most raw materials” (Ref. , footnote 2). All of these examples were of exposure to natural sources of radiation.
The recent IAEA Safety Standards Series guidance was published in August 2004, i.e. after the ICRP draft recommendations. It may therefore be seen as a commentary on the ICRP draft whose earlier forms have been in circulation since 2003. The IAEA Safety Standards Series guidance re-iterates the above BSS standards, that is, it refers to exclusion levels which are restricted to naturally-occurring radiation. However the ICRP draft significantly goes beyond this to include man-made nuclides. This is unfortunate, as the IAEA clearly has recognised.
The sections concerning exclusion should be withdrawn
8. Lax Exclusion Levels.
The proposed exclusion levels are lax. For example, as shown below, for a few nuclides, they exceed the values used in Codex Alimentarius, (as used by the ICRP’s Generic Action Levels for Foodstuffs (see table 1), and CFILs (see table 2).
Table 1 Generic Action Levels for Foodstuffs (from an ICRP Task Group, April 2004)
reproduced from the Committee on Food Additives and Contaminants of the Codex Alimentarius Commission [Codex Alimentarious 2004].
Recommended levels of activity for taking intervention measures for foodstuffs that may remain contaminated after a radiological accident
Radionuclides in foods Guideline (Bq/kg)
238 Pu, 239 Pu, 240 Pu, 241 Am 10
90 Sr, 106 Ru, 129 I, 131 I, 235 U 100
35 S, 60 Co, 89 Sr, 99 Tc, 103 Ru, 134 Cs, 137 Cs, 144 Ce, 192 Ir 1,000
3 H, 14 C 10,000
CFILs were introduced by Council Regulations (Euratom Nos 3954/87, 944/89 and 2218/89) following the Chernobyl accident to restrict the export of contaminated foodstuffs in Europe. These limits in force at present are set out in Table 3.
Table 2 Community Food Intervention Levels - Bq/kg
Baby Foods Dairy Produce Other Foods
Sr-90 75 125 750
I-131 150 500 2000
Cs-137 400 1000 1250
Pu-239 1 20 80
There is something very peculiar about tables 1 and S2. For example, if the concentration of Sr-90 in food following a nuclear incident were found to be 100 Bq/kg, would this level result in the food being declared unfit for consumption (via table 1), or would it be declared non-radioactive as it is exempt from further regulation (via table S2)?
The ICRP’s proposed exemption levels are much too lax in comparison with other guides and should be withdrawn and replaced with tighter standards.
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