|Thank you for the opportunity to comment (a second time) on the ICRP document Draft Recommendations of the International Commission on Radiological Protection, released on 5 June, 2006. In sum, ICRP is making recommendations which ignore new scientific data in favor of doing nothing and essentially ensuring that national radiation regulators have inadequately protective radiation standards. ICRP averages radiation damage over age and gender, leaving the most vulnerable humans unprotected. ICRP has completely disregarded radiation damage to future generations past the second one. ICRP is allowing low-level releases of radiation while claiming not to know exactly what damage is done at these doses. ICRP is washing its hands of responsibility for its inadequate recommendations and any regulations which follow.
NIRS recommends that ICRP members read Late lessons from Early warnings: the precautionary principle 1896-2000 written by the European Environment Agency. Upon reviewing Late lessons, one finds a comparison between actual use of precaution and the ICRP principles of justification, optimization and limitation (now called constraint). The agency looks briefly at how these principles, adopted in 1977, have increased protection from radiation exposure and found that, in general, these principles have not been protective enough even for controlled circumstances such as medical radiation applications. To quote the Agency:
For instance, the risk rate for radiation-induced cancer was perceived (by ICRP) as four to five times higher in 1990 as compared to 1977. This resulted in changes in dose limits but was a belated response to mounting incontrovertible evidence, a situation which has been a recurring theme in the history of radiation protection, where precaution has sometimes been lacking despite the clear warnings given from the discovery of radiation to the present day.
Not that “mounting incontrovertible evidence” is required to take precautionary action. Late Lessons also points out that the case studies it reviews, including the one on radiation, all create a key question:
…how to acknowledge and respond not only to scientific uncertainty but also to ignorance, a state of not knowing from which springs both scientific discoveries and unpleasant surprises…
ICRP has chosen to acknowledge and respond to the dangerous uncertainties of radiation doses at lower levels by ignoring them. Clearly, ICRP is not practicing precaution in its recommendations, all protests and claims to the contrary.
Many of the comments below were introduced in previous NIRS comments on both the first draft Recommendations and Annexes A & B and, sadly, ICRP has not reflected these concerns in their current recommendations. ICRP is indeed running into a clash between what science is unable to tell us and the political and philosophical systems we must erect to fill this gap. Instead of washing its hands of responsibility for the role it plays in setting national radiation standards, ICRP must find a way to address the potentially damaging unknowns of radiation exposure at low doses. The Precautionary Principle is one way to address this, at least in part.
Areas of concern include:
1) Collective Dose; Exemption/Exclusion. ICRP recognizes that the Linear-no-Threshold model is still favored by recommending and standard-setting bodies.
Despite this, ICRP is willing to risk the uncertainty they claim exists at low dose levels by both inclusion of a DDREF and their recommendation to release or allow exposures at low dose levels below a dose limit. If science is so uncertain what is happening at these lower dose levels, how can ICRP condone either releases or a DDREF? On the other hand, ICRP is unwilling to risk the uncertainty of using collective dose for assessing harm at these low doses. In both cases the same methods, formulas and assumptions are often used. This is obviously hypocritical and certainly not protective.
2) Gender Averaging and age averaging. We note that for protection purposes, ICRP uses averages and judgments which do not fully account for particularly susceptible individuals. This favoring of the group rather than the individual results in the most vulnerable such as children, fetuses and the immune-compromised not being protected at lower doses. To remedy this, ICRP should base effective dose for protection purposes on the most vulnerable for cancer and genetic effects. Since there is no recognized radiation dose that will surely not result in some damage, this will be challenging, but ICRP could adjust the standards to be more protective rather than ignoring the “no threshold” premise and the new science at low, cellular doses.
3) Genetic impacts/Heritable disease
ICRP reduces the impact of radiation on heritable disease by increasing the amount of baseline mutations. This naturally makes radiation exposure contribute less to the total number of mutations, hence ICRP has lowered the mutation risk of radiation. ICRP predicts that there would be a total of 738,000 genetic diseases from baseline. Per gray of exposure per 1 million people there would be at most 4,700 additional genetic diseases in the first generation after exposure and an additional 6,700 to the second generation at most over baseline occurrences. ICRP does not address synergistic effects at all which means that of the baseline diseases, they have no idea what part radiation played, if any; or which diseases would have occurred at all without radiation exposure. We have no idea if radiation enhances the deleterious effect of other substances, whether or not they are recognized as dangerous (see caffeine study below). ICRP will not predict genetic disease past the second generation because they claim the information we have is not adequate and these predictions would be useless. But ICRP is also making a short-sighted, unscientific and potentially detrimental value judgment that children and grandchildren are who we care most about. Devaluing future generations simply because the mathematical prediction of disease is difficult or incorrect is inequitable at best, detrimental to health at worst.
4) Synergism. There are hardly any studies on synergistic effects of radiation and other toxins such as organochlorides, heavy metals and even common substances. True to form, ICRP does not account for any of these potential effects and in fact doesn’t even mention or recognize this scientific shortcoming. This issue would be particularly fertile ground for using precaution. There are some studies on synergistic effects of radiation and common substances such as caffeine. Consider research at Colorado State University which shows that caffeine increases the damage radiation can cause in hamster cells. This raises the question of synergistic effects which BEIR VII panelists (USNAS radiation & health panel) have admitted are hardly known.
5) Weighting factors. Tissue weighting factors are used as one factor by ICRP in determining effective dose. Tissue weighting factors are (unfortunately), derived almost exclusively from the Hiroshima Nagasaki radiation health studies. As quoted from Recommendations Draft :“With a few exceptions, the parameters in the risk models are estimated using cancer incidence data from the studies of the Japanese atomic bomb survivors”. Since these studies were largely health effects from bomb radiation, one cannot just assume without explanation that their risk can be equated with internal doses to organs. ICRP has the responsibility to explain why they feel they can equate radiation from a nuclear bomb explosion to internally incorporated radionuclides like strontium-90, tritium or cesium-137 from nuclear reactors and other “civilian” processes. Perhaps ICRP has accounted for this difference, but this is unclear from reading of the related Annex. ICRP has additional shortcomings because they include tissue weighting factors that are gender averaged; and ICRP feels that there is at present insufficient data for prenatal health so they choose to ignore this damage altogether.
6) Bystander Effect & Genomic Instability. ICRP argues that these effects are shown in epidemiological studies and do not need to be understood further for protection measures. This may indeed NOT be the case for several reasons. First, many epidemiological studies deal with external dose. Epidemiological studies of inhalation and ingestion need a full accounting to get a valid picture of actual damage. Additionally, many epidemiological studies which do examine internal dose do so not from actual measurements of material ingested or inhaled which is then equated to disease incidence, but from dose formulas that are full of judgment calls, errors and predictions which may not be right (see tissue weighting factors above). Accepted scientific practice often makes health effect assumptions based on the amount of radiation released NOT the actual increase in disease. In these studies a level of damage is presumed before an accounting of disease incidence. Authors often argue, despite increasing disease, that only a fraction of the disease increase could be from radiation because the doses simply weren’t high enough. Yet, ICRP itself concludes that we don’t know enough about the low-dose ranges to predict what damage there may be. Assuming one believes this (there is evidence that we do know something about low dose harm) then it makes no sense to discount “extra” diseases as due to other phantom factors when radiation is a perfectly good, often the only, explanation. The power of studying the bystander effect and genomic instability is that these mechanisms are precisely what could give us insight into health effects at lower doses: the effects ICRP says we don’t know enough about to protect against. To use epidemiology to discount genomic instability and the bystander effect is therefore, folly. These “unknowns” of radiation science are exactly why the precautionary approach needs introduction into this process. As the gene pool weakens from chemical and radiological insults, epidemiological data may have to be reevaluated since population susceptibilities are likely to change to favor more easily-induced damage.
7) Non-cancer effects, especially heart disease, need to be reevaluated. They are not accounted for fully in these recommendations. For instance, heart disease can be both heritable from radiation damage to parent AND a result of current generation irradiation.