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Unscear 2013 — Fukushima report commentary by Safecast

“Evaluations of the accuracy and relevance of this report should be based on close reading and an understanding of issues such as those presented in this commentary at the very least. It is an extremely challenging document to navigate and parse, and perhaps this is cause for criticism in itself. There is room for valid criticism in several areas, and several underlying assumptions deserve scrutiny. Now is a good opportunity for informed commentary and feedback, because the forward steps taken in this report show that incremental change is possible. The only way to provide useful criticism is to examine the report in detail and address specific content”

Azby Brown – SAFECAST – 30 April 2014

http://www.slideshare.net/safecast/unscear-2013-fukushima-final-report-commentary-ownload

  • 1. Guide to the UNSCEAR 2013 Fukushima report (released April 2, 2014) Azby Brown, SAFECAST Revised April 30, 2014 v04 [This revision: Clarifies that “10% per Sv” refers to fatal solid cancer risk, not to cancer incidence in general.] [Previous revision: Includes feedback from an UNSCEAR contact who was able to closely observe the drafting of the report, but who asked to remain anonymous. Their comments mainly concern clarification of the report’s stance on LNT, DDREF, and collective dose; the approach taken towards release estimates; and UNSCEAR’s intended role.] This is a work in progress. Comments and corrections welcome. http://www.slideshare.net/safecast/unscear-2013-fukushima-final-report-commentary-v02 ++++++++++++++++++++++++++ ++++++++++++++++++++++++++ The full title of the report is: SOURCES, EFFECTS AND RISKS OF IONIZING RADIATION UNSCEAR 2013 Report It includes: VOLUME I: Report of the United Nations Scientific Committee on the Effects of Atomic Radiation to the General Assembly Scientific Annex with appendices Released earlier: VOLUME II: Scientific findings on effects of radiation exposure of children Annex B . Effects of radiation exposure of children Available at: http://www.unscear.org/docs/reports/2013/13-85418_Report_2013_Annex_A.pdf ++++++++++++++++++++++++++ ++++++++++++++++++++++++++
  • BRIEF SUMMARY: The report’s findings are summarized in greater length below (along with many caveats, exceptions, and explanations). But very briefly, some of the key points of the report include: –AGE GROUPS: The report provides separate dose and health risk estimates for three age groups: 1yr old, 10 yr old, and 20 yr old. This summary will look mainly at doses for 1 yr olds, because they received the highest doses. –GEOGRAPHIC DIVISIONS: Geographically, it is split into four areas: Group 1: Parts of Fukushima Pref. that were evacuated Group 2: Parts of Fukushima Pref. that were not evacuated Group 3: Nearby prefectures (Iwate, Miyagi, Tochigi, Gunma, ibaraki, Chiba) Group 4: The rest of Japan. –METHODS: Because not enough actual dose measurements (in-vivo data) were available for the early weeks of the disaster, the dose estimates are primarily based on models derived from ground deposition data. Atmospheric Transport and Dispersion Modeling (ATDM) was used to derive concentrations in air when necessary, such as when estimating inhalation doses. The range of doses for each settlement or district was estimated and cross-checked against other available data. The dose ranges presented in most graphs and tables are based on the averages of all the settlement or district doses in a particular geographic zone (such as Group 2: Parts of Fukushima Pref. that were not evacuated), not necessarily the highest and lowest doses estimated for that zone. The range of uncertainty is usually such that actual doses could be as little as 30% of the estimated average, or as much as 3 times more. This is confusing, but as described below, the uncertainties needed to be acknowledged, though the available data often did not allow them to be determined more precisely. — FIRST-YEAR DOSES, UNEVACUATED AREAS: The highest average first-year doses (in addition to background exposures) were received by: –Effective dose (full body): 1 yr olds in Group 2 (non-evacuated areas of Fukushima pref) : 2.0- 7.5mSv –Absorbed dose to thyroid: 1 yr olds in Group 2: 33-52 mSv –EVACUATION ZONE: The WHO Fukushima reports did not include dose estimates for residents of the original 20km evacuation zone. This report does. These were estimated as the sum of doses received before and during evacuation, and doses received during the remainder of the year at the location to which they were evacuated. Highest average first-year dose ranges for people from evacuated areas (1-year olds): “Precautionary” evacuation areas, i.e early evacuations (Futaba, Okuma, Tomioka, Naraha and Hirono etc) –Effective dose: 1 yr old,: 1.6 – 9.3mSv –Absorbed dose to thyroid: 1 yr old: 15-82 mSv Later “deliberate” evacuation areas (Iitate, Namie, Kawamata, etc) –Effective dose: 1 yr old,: 7.1 – 13 mSv –Absorbed dose to thyroid: 1 yr old: 47-83 mSv] –ACCUMULATED DOSES: Dose estimates are provided for the first year, accumulated after 10 years, and accumulated after 80 years. Group 2, 1yr old effective dose: 1 year exposure; 2.0-7.5 mSv 10 year exposure: 2.1 -14 mSv
  • 2. lifetime (80 years): 2.1-18 mSv –COLLECTIVE DOSES: There was reportedly much debate about whether or not to include these, but collective effective doses and collective absorbed doses to the thyroid for the Japanese public are described. Collective effective dose (in man-sieverts): 1st yr: 18,000 after 10 yrs: 36,000 after 80 years: 48,000 The report does not take the additional step of calculating the illness and mortality implications of this (and gives reasons why this was not done), but based on LNT it can be calculated that about 5000 persons in Japan will die of cancer from this radiation exposure over the course of 80 years. –AVERTED DOSES: Despite the problems with the evacuation, they estimate that thyroid doses of infants would have been about 10 times higher without it, i.e. up to 750 mGy instead of about 80 mSv. They also estimate that residents of a number of towns would have received lower doses if they had not evacuated. –DOSES TO WORKERS: These are dealt with extensively, and the data provided by TEPCO is scrutinized and in some cases its validity could not be confirmed. –UNCERTAINTIES: The estimation models introduce various uncertainties. The doses are generally given as averages for districts or settlements. Doses to individuals in each settlement might be 30-50% lower than the settlement average, or up to 2 or 3 times higher. If doses could be based on in-vivo data, the uncertainty range would be much smaller. [According to the UNSCEAR contact, the available data did not generally allow an actual uncertainty analysis, so statements about uncertainty are the result of sensitivity analyses instead. This is a bit confusing but the important thing to keep in mind is that statistical uncertainty bounds are generally not provided, while rough estimates of possible variation are. The uncertainties will be revisited in the future.] –COMPARISONS TO OTHER DATA: The dose estimates coincide fairly well with those provided by WHO, but are about a factor of two or more higher than what has been shown by personal dosimetry and WBC monitoring. Nevertheless all of these generally agree within an order of magnitude. –DOES IT UNDERESTIMATE DOSES?: Taken as a whole, the report’s dose estimates for the public can be said to err on the side of overestimation, and no data has emerged yet that suggests gross underestimation of the doses themselves. The range of variability has been clearly noted, along with other uncertainties. They state that, “in some cases sizeable population groups may have been exposed to doses at the higher end of this distribution.” The report might be criticized for not illustrating the range of uncertainty more informatively in the dose graphs and tables themselves. –HEALTH IMPLICATIONS: The report states, “No discernible increased incidence of radiation-related health effects are expected among exposed members of the public or their descendants.” This is not a claim that no disease will occur. They explain clearly and precisely that health risks might exist, but: –Any increase will be within the bounds of normal variation of the disease without radiation. –Risks can be inferred theoretically but not directly detected with current science or statistically. –Compared to normal occurrence of the disease, the risk is relatively small. –The group of people affected is too small to make a meaningful statistical analysis. –They’re not saying they don’t care about the people who are affected, however few they might be. Nevertheless this language is easy to misinterpret, oversimplify, or just misquote. Disease estimates in the report are based on current radiation risk standards, which seem to have been carefully applied, with a higher risk per dose being assumed in general than in the past. Contrary to some claims, doses themselves do not seem to be underestimated, and arguments that health effects are systematically discounted in the report will need to be based on criticism of the underlying standards themselves, particularly concerning very low doses. Some reliable research already points at the potential need for revising the standards, and UNSCEAR itself has a number of things on its agenda to discuss in this regard (including low-dose issues in general, DDREF, age and sex functions, and thyroid), but this process has never moved quickly, and we should expect it to take years. [An earlier version of this summary listed ICRP and BEIR VII as the standards being applied in this report, but an UNSCEAR contact explained that while UNSCEAR has its own risk models, particularly what’s known as UNSCEAR 2006, these are due for revision, and so this report basically adopts the models used by WHO in its earlier Fukushima risk assessments.] –THYROID CANCER: In particular, the report notes, “An increased risk of thyroid cancer in particular can be inferred for infants and children. The number of infants that may have received thyroid doses of 100 mGy is not known with confidence…” but is estimated to be fewer than a thousand. The thyroid dose estimates in the report are up to five times higher than what the limited in-vivo screening data suggest. The report uses thyroid screening data that was available by the end of July 2013, and discusses at length the anomalies and thyroid cancers that have been discovered, and the implications. –ASSUMPTIONS IN THE REPORT INTENDED TO HELP AVOID UNDERESTIMATION AND WHICH MIGHT LEAD TO HIGHER DOSE AND/OR RISK ESTIMATES: –The report uses LNT to infer that risks from doses under 100 mSv exist. [The UNSCEAR contact explained that the report does not in fact “clearly endorse” the use of LNT, as I had originally written, because opinion on this was not unanimous. Nevertheless, the dose and health effects calculations assume risk at low doses as predicted by LNT. This is a compromise that the committee could agree on.] –The report abandons the assumption that doses received over time are less damaging than those received all at once, and so uses a DDREF of 1.0. [Similarly, according to the UNSCEAR contact, while some committee members wanted to officially change DDREF to 1.0, the purpose of the report was to describe the consequences of the Fukushima accident, not to review risk models per se; the WHO had used DDREF = 1.0 in its calculations, so it was adopted here as well.] — The added lifetime fatal cancer risk per Sv of exposure has commonly been assumed to be 5%, but in this report, UNSCEAR effectively doubles the assumed risk to 10% per Sv. –Lifetime doses are based on a period of 80 years, instead of 70, because of longer Japanese lifespans. This leads to higher doses because people are assumed to be exposed 10 years longer. –UNSCEAR could not determine exactly who among the public received potassium iodide (KI) and when, so in their calculations they assumed that no-one did. Also, they did not assume any benefit in reducing thyroid doses from the high iodine content of the Japanese diet. –The report assumes that no-one had or will have better shelter than that provided by wooden buildings, i.e., it uses the lowest sheltering factor. –Accumulated dose estimates over time assume that no remediation would be done and so no reduction of doses will be achieved by it.
  • 3. –They assumed that 100% of the food eaten by Fukushima residents was produced locally, and that all of it contained at least 10Bq/kg of Cs but not more than 100 Bq/kg; the overall contamination levels were based on official food testing databases for marketed food. They note that measurements of food actually consumed by families indicate much lower levels of internal contamination from food than this modeling suggests. –ASSUMPTIONS IN THE REPORT THAT MIGHT LEAD TO UNDERESTIMATES OF DOSE AND/OR RISK: — Assumes that doses from inhaling resuspended particles, etc. are insignificant: This may in fact be true, but it would be better to include these, along with a discussion of the kinds of situations that could make these exposures more significant. — Assumes that direct doses from seafloor sand and sediment are insignificant: They did not include possible exposures from offshore sediment or sand, reasoning that these would only be relevant outside the 20km evacuation zone, where they would contribute only small exposures, whereas within 20km access is restricted. Access has been relaxed in many areas closer to the NPP, however, so more care should probably have been taken to determine potential exposures, particularly in coming years. –UNSCEAR estimates ocean releases of 3-6 PBq direct, and 5-8 PBq from the atmosphere to the ocean. While there’s a wide range of ocean deposition estimates, and a fair amount of relevant data was released after this report’s Sept. 2012 cutoff date, Aoyama gives 15PBq as his estimate of deposition from the atmosphere to the ocean, and Buesseler has said that the estimates for direct releases to the ocean are converging at 15-30 PBq. UNSCEAR’s estimates for this are on the low end. [The UNSCEAR contact explained that actual release quantities were used as intermediate values, to help determine the relative ratios of nuclides that were released; assessments of nuclide levels in the environment were based on actual deposition measurements wherever possible.] –Assumes that food screening will continue in an effective manner in coming decades; in reality the continuing political will to do so cannot be guaranteed, and doses from contaminated food could increase in the future. It would have been instructive to include what the food intake doses would be if testing and intervention were stopped. –PSYCHO-SOCIAL EFFECTS NOT COVERED IN DETAIL: The report notes the importance of mental health issues and a notable increase in these problems in Fukushima and elsewhere, and explains that they examined these, but only briefly, noting that, “Evaluating such effects is not part of the Committeeʼs mandate.” [This is clearly within WHO’s mandate, though, according to the UNSCEAR contact]. –NON-HUMAN BIOTA: The report discusses findings from a number of studies of effects on terrestrial and ocean organisms, and concludes that effects on non-human biota in the marine environment would be confined to areas close to where highly radioactive water was released into the ocean, and any radiation effects for terrestrial organisms would be constrained to a limited area where the deposition density of radioactive material was greatest. The available data would seem to be inadequate to make firm estimates, however. [See comments below about how this overlaps with the mandate of UNEP] –SOURCES OF INFORMATION: Primary sources are predominately Japan gov’t agencies, other member states (like US DOE), TEPCO, and international intergovernmental organizations (WHO, CBTO, IAEA, FAO, WMO). Secondary sources used for independent confirmation of official data include several NGO’s, including CRIIRAD, ACRO, Greenpeace, Union of Concerned Scientists (UCS), and SAFECAST. In addition, the committee made use of hundreds of peer-reviewed studies, most of which can be considered independent. –end of brief summary– ========================================================================================== ========================================================================================== LONG SUMMARY: GENERAL COMMENTS: This report is long-delayed, and is apparently the first time a major accident report took UNSCEAR more than three years to produce [The UNSCEAR contact commented that they have only produced one major accident report besides this, for Chernobyl, and that took two and a half years]. The reasons for this include, apparently, long delays in obtaining information from Japanese sources, difficulty reaching consensus on several points, and the desire to integrate information which became available after the initial Sept., 2012 cutoff date. The Japanese govt proposed that the report be undertaken, and it was approved as a “future program of work” in May, 2011. A nearly-complete draft was produced in May 2013, and then entered a long approval, amendment, and publication process. The findings were presented to the UN General Assembly in Oct, 2013, and it was approved in Dec. 2013, and released on April 2, 2014. The authors express frustration with the amount of time required to move a report like this through the system on p.12, saying: “Nevertheless the Committee suggested that the General Assembly might request the United Nations Secretariat to continue to streamline the procedures, recognizing that, while maintaining quality, the timeliness of their publication is paramount to fulfil the expected accomplishments approved in the programme budget, and expecting that the report ought to be published within the same year in which it is approved.” [The UNSCEAR contact stressed that these sorts of administrative delays are a problem with any report it issues, not just the Fukushima report.] Those who have been following know that the draft report was the object of contention and protest, and the final report has been as well. Some of the criticism is valid, while some seems based on misunderstanding or misrepresentation of what’s actually in the report. In Oct 2013, Physicians for Social Responsibility (PSR), as well as other groups including the International Physicians for the Prevention of Nuclear War (IPPNW), released a list of 10 criticisms, based on the May 2013 draft, which had been leaked: http://www.ippnw.de/commonFiles/pdfs/Atomenergie/ Ausfuehrlicher_Kommentar_zum_UNSCEAR_Fukushima_Bericht_2013__Englisch_.pdf It’s worth keeping the points they made in mind while reading the final report. Most of their criticisms seem to have been addressed to some degree, though in fact many already had been in the draft. We heard unconfirmed reports that committee members had been discussing most of the issues raised and gathering support for the inclusion of DDREF=1 and collective dose which were meeting resistance, and that the protest and widespread circulation of the leaked draft in fact were making it more difficult for people pushing for changes within the agency to do so effectively. IPPNW has issued a new press release, in German only so far, restating several of the criticisms, and they may well produce a longer critique of the final report: Original: http://www.ngo-online.de/2014/04/2/fukushima-unscear-bericht/
  • 4. Machine translation: https://nuclear-news.net/2014/04/03/unscear-cover-up-of-health-consequences-of-the-nuclear-disaster/ It may be worthwhile at some point to compare these criticisms with what’s actually in the report. The process of producing a report like this is unwieldy, overly politicized, and open to incremental change only. It’s like steering an oil tanker with dozens of captains. Seen as a whole, it’s easy to call the entire international nuclear regulatory apparatus dysfunctional, particularly in times of emergency when information needs to be gathered and decisions made quickly. This report involved a committee of over 80 people from 18 countries, and the Japanese contingent played an important role. We have heard rumors that Japanese committee members strongly resisted some of the changes, particularly using DDREF =1 (which means that doses received over a long period of time are assumed to have the same effect as those received all at once; until now it had been assumed that they were about half as damaging). [The UNSCEAR contact commented that UNSCEAR itself is intended to be a scientific body, not a regulatory agency, is not involved in policy decisions like the IAEA, and is not directly involved in either emergency response or radioprotection. In addition, he pointed out that the committee that was convened for this report was much larger than any UNSCEAR has assembled previously; they have usually worked with a small group of experts. The size of the committee presented organizational challenges, but the overall depth of expertise it made available and the wide range of opinions represented resulted, he felt, in a stronger committee. Some areas where differences of opinion existed include LNT, DDREF, and collective dose, and the language with which these are dealt with in the report often reflects compromise. Nevertheless, ultimately everyone on the committee approved the final version that was released.] Despite the problems, my initial take is that this report is better than expected in many important respects, and not as bad as some critics make it out to be. UNSCEAR is not a monolith, and a few prominent nuclear critics who have been lobbying for decades for greater recognition of the harmful effects of low-dose radiation have had very positive things to say about Malcolm Crick, the UNSCEAR Secretary who oversaw the report. In the end, a report like this is a compromise, and the system makes it easier to block things than to get them included. Despite the fact that the language in the report is generally very precise, and the sections that treat the issues in depth describe many assumptions, qualifications, and uncertainties, almost all press reports will be based on the brief summary, and it’s easy to misinterpret, oversimplify, or just misquote this. This means it can and will be used to support various agendas, and also as a straw man for critics. There should be a better way: a process that is quicker, more open, more easily understood by journalists and the public, less focussed on producing a massive “authoritative” document and more on rapidly evaluating, discussing, and making use of a broad spectrum of information as it comes in. ++++++++++++++++++++

  • STRUCTURE (how to find things): The report is repetitive, because it’s structured as a short 17 p. summary report, followed by an annex whose 70p main text explains everything in more detail, which itself is followed by over 200 pages of appendices which go into even more detail. This amounts to three increasingly detailed treatments of the same issues. Each level of treatment covers: the radioactive releases, dispersion, and deposition (atmospheric and to the ocean); dose assessments (to the public and to workers); health implications (for the public and for workers); and effects on non-human biota (terrestrial and aquatic). In addition, the uncertainties are described and discussed at length. These are described in the main text as well, but Annex A, Chp IV-E (p 60-61) and Appendix C, Chp IV (p. 199-204) in particular go into greater depth. It’s very important to read these sections in order to get an idea of how altering some assumptions or using a different data set might affect the ultimate dose and health estimates. Nevertheless, in most cases the range of uncertainty is given when the conclusions are first presented. This might seem like an unnecessarily confusing way to structure this information, especially since most of us can imagine how easy it would be to navigate if it was all hyperlinked and readers could easily go from a brief summary paragraph to increasingly detailed treatments of each subject. But this is how UNSCEAR always does it, as does WHO and other agencies, particularly UN-related ones. People soon learn that the meat is in the Annex, and the geeky detail is in the appendices. From now on this report will be probably be referred to as “UNSCEAR 2013 Annex A,” even though it was released in 2014. And for those who’ve forgotten, last year they issued “UNSCEAR 2013 Report, Volume II, Annex B: Scientific findings on effects of radiation exposure of children.” This is also well worth reading. ++++++++++++++++
  • GEOGRAPHIC AND AGE BREAKDOWN [IV-C. 80] The report provides separate dose and health risk estimates for three age groups: 1yr old, 10 yr old, and 20 yr old. Geographically, it is split into four areas [the best maps are C-VI — VII] Group 1: Parts of Fukushima Pref. that were evacuated Group 2: Parts of Fukushima Pref. that were not evacuated Group 3: Nearby prefectures (Iwate, Miyagi, Tochigi, Gunma, ibaraki, Chiba) Group 4: The rest of Japan. Dose estimates are provided for the first year, accumulated after 10 years, and accumulated after 80 years. ++++++++++++++++
  • ESTIMATED DOSES; In most cases, doses for Group 1 (evacuated areas) are described separately from Groups 2, 3, and 4. Most useful table: Table C6 [Appendix C75]. Table C6 summarizes the estimated district- or prefecture-average effective doses received in the first year following the accident, for 20-year-old adults, 10-year-old children and 1-year-old infants residing in the non-evacuated districts of Fukushima Prefecture (Group 2), the Group 3 prefectures and the remaining prefectures in Japan (Group 4). Most useful maps: Figures C-VI — VII [Appendix C76]. Figure C-VI shows the district-average effective doses in the first year following the accident for 1-year-old infants living in districts of Fukushima Prefecture and some districts of the Group 3 prefectures that were not evacuated. Figure C-VII. Estimated total effective doses to 1-year-old infants in the first year following the accident. The main map shows the prefecture-
  • 5. average effective dose. Fukushima Prefecture average includes non-evacuated districts only. The inset map shows the district-average effective doses for non-evacuated districts of Fukushima Prefecture (See also Table 5, Table 10) +++++++
  • DOSES IN UNEVACUATED AREAS: 1 year-olds are generally known to receive higher doses in most exposure situations, so estimates for them provide a good “worst-case” overview. +++++++++
  • The highest average first-year doses in these groups were received by: –Effective dose (full body): 1 yr olds in Group 2 (non-evacuated areas of Fukushima pref) : 2.0- 7.5mSv –Absorbed dose to thyroid: 1 yr olds in Group 2: 33-52 mSv Table 7 gives estimated average accumulated doses over time: Group 2, 1yr old effective dose: 1 year exposure; 2.0-7.5 mSv 10 year exposure: 2.1 -14 mSv lifetime (80 years): 2.1-18 mSv +++++++++
  • These are in addition to normal background exposures. A dose range was determined for each district in Fukushima, and the ranges given above are based on the averages of each district. Uncertainties and variability are noted below. In particular, the report notes that in many cases the estimates from modeling are higher than what actual in-vivo measurements show [described in detail in sections sections IV-E and F] +++++++
  • Thyroid doses for people in unevacuated areas: “For districts of Fukushima Prefecture that were not evacuated (Group 2), the highest estimated absorbed doses to the thyroid in the first year were to individuals living in Iwaki City and Fukushima City. The highest district-average absorbed dose to the thyroid of a 1-year-old infant in the first year was estimated to be about 50 mGy for Iwaki City (see table 5). Approximately one third of this dose was due to inhalation and two thirds due to ingestion. The estimated doses to the thyroid for adults in the first year were about 30% of those for 1-year- old infants. These doses were mostly received over the first few weeks after the accident.” [IV-D-1.95]. In addition, “the Committee estimated that about 35,000 children in the age range of 0−5 years lived in districts where the average absorbed dose to the thyroid was between 45 and 55 mGy.” [Appendix E30] ++++++
  • DOSES IN OTHER PREFECTURES: “For the districts of the Group 3 prefectures (Chiba, Gunma, Ibaraki, Iwate, Miyagi and Tochigi), the district-average effective doses to adults were in the range 0.2 to 1.4 mSv for the first year, including 0.2 mSv from ingestion of food in the prefectures of Chiba, Gunma, Ibaraki, Miyagi and Tochigi. In Iwate Prefecture, the effective dose due to ingestion of food was 0.1 mSv, the same as for the remainder of Japan. The prefecture-average effective dose to adults for the prefectures in the remainder of Japan was in the range 0.1 to 0.3 mSv for the first year, with ingestion contributing 0.1 mSv and generally being the dominant pathway.” [IV-D-1.93] Based on available market-basket and duplicate meal studies, these ingestion doses seem to be overestimated, particularly for the Group 4 prefectures (rest of Japan). ++++++++
  • DOSES TO RESIDENTS OF EVACUATED AREAS: The most useful table is Table C12: Estimated settlement-average absorbed doses to the thyroid of 1-year-old infants evacuated from localities of Fukushima Prefecture [p191]. It includes breakdown by location, also what average doses would have been if these groups had not evacuated. The report describes the method used: “Doses in the first year to people evacuated from Group 1 areas (Futaba, Hirono, Namie, Naraha, Okuma, Tomioka, Iitate, Kawamata, Minamisoma, Tamura, Kawauchi and Katsurao) were estimated as the sum of doses received before and during evacuation, and doses received during the remainder of the year at the location to which they were evacuated.” [ IV-D-2.102] [See table 6]. This is much less straightforward than estimating doses to people in unevacuated areas, and basically means estimating their doses for the first few days prior to and during evacuation (weeks or months for the late evacuations done in Iitate, Namie, Kawamata, and elsewhere), based on atmospheric and deposition models, and then applying dose estimates for the areas where the groups resided for the remainder of the year, based on 18 sample movement scenarios. There is no easy way to provide a map for this. The results suggest that evacuees from Tamura, Minamisoma, Kawauchi, Katsurao, and Yamakiya would have had smaller doses if they had stayed in place and not evacuated. The scenarios are based on actual movements of evacuees as reported in surveys, and have been selected to represent some of the most common routes and timings, but can’t be assumed to cover all actual evacuation patterns. +++++++++
  • Highest first-year average dose ranges for people from evacuated areas (1-year olds): “Precautionary” evacuation areas, i.e early evacuations (Futaba, Okuma, Tomioka, Naraha and Hirono etc) –Effective dose: 1 yr old,: 1.6 – 9.3mSv –Absorbed dose to thyroid: 1 yr old: 15-82 mSv Later “deliberate” evacuation areas (Iitate, Namie, Kawamata, etc) –Effective dose: 1 yr old,: 7.1 – 13 mSv –Absorbed dose to thyroid: 1 yr old: 47-83 mSv]
  • 6. +++++++++ Again, these estimates are associated with various uncertainties. These dose ranges are based on averages determined for each settlement (generally the smaller towns or villages which comprise the municipalities), and doses to individuals in each settlement might be 30-50% lower than the settlement average, or up to 2 or 3 times higher. [ IV-B-2.171] The report notes that, “Some infants may have received thyroid doses of 100 mGy or more.” [III-2..32] Elsewhere, it states that thyroid doses “ranged up to about 150 mGy” [Appendix E33]. This is confusing. Details for each settlement and for districts in other prefectures can probably be found in the electronic supplements, but it would have been helpful to provide dose ranges based on absolute minimum and maximum estimates found in any district or settlement in each geographic group, instead of ranges based on the averages of the districts. The report states: “Within Fukushima Prefecture, the districts that partly fall within the 20-km evacuation zone (Minamisoma City) and those with high ground deposition density (Fukushima City, Nihonmatsu City, Koori Town, Otama Village, Koriyama City, Motomiya City, and Date City) had the highest estimated effective doses to individuals who were not evacuated, with the district-average effective doses to adults in the range 2.5 to 4.3 mSv in the first year…Average effective doses in the first year for 1-year-old infants were estimated to be up to twice those for adults.” [IV-D-1.92] ++++++++ COMMENT: These estimates coincide fairly well with those provided by WHO, but are about a factor of two or more higher than what has been shown by personal dosimetry and WBC monitoring. Not enough of either of these is available to be conclusive, but [Figure C-XI] shows estimates for different age groups in Fukushima City over time. It indicates that an average 1yr old in Fukushima City could have received 7.5 mSv in the first year: 5 mSv of this external, 2 mSv from ingestion, and an adult about 3 mSv external, and 1 mSv from ingestion. Personal dosimetry of over 36,000 children and pregnant women in Fukushima City in late 2011, however, indicated that over 50% received less than 1mSv exposure for the year. Available WBC data suggests the internal exposures of the great majority were below 1mSv. Neither of these in-vivo datasets can tell us much about exposures during the first few weeks, which is why UNSCEAR has relied on models. Nevertheless, compared to these actual measurements the estimates in the report seem to be high. UNSCEAR acknowledges this in several places [IV- F-1.117-118] [Appendix C141-143]. Based on WBC data for 10,000 evacuees done between July 2011- Jan 2012, UNSCEAR estimates the average effective dose from the intake of 134Cs and 137Cs since March 2011 for almost all evacuees to be less than 1mSv, with average internal doses of about 0.05 mSv for adults and about 0.03 mSv for adolescents. About one person in 5,000 adults and adolescents was estimated to have a 1 mSv internal exposure [Appendix C141]. These in-vivo measurements were not used in generating dose estimates, however, but were included for the sake of comparison. UNSCEAR has indicated the need to conduct more in vivo measurements in order to refine their estimates, particularly in regards to current and future levels of exposure [VIII-F.230.e]. To date, while a lot of in-vivo data is available, and UNSCEAR may have underutilized it here, government programs for personal dosimetry and WBC have been too inconsistent and not widespread enough for them to be useable as the primary basis of dose estimation. This is unfortunate, because in-vivo measurements potentially have far less uncertainty than models. With a few notable exceptions, those who established these programs in Fukushima seem not to have thought about the importance of consistency and coordination, both technically and in reporting results, for accurately assessing public health risks. NOTES: –Averted doses: “The Committee estimated that the evacuation of settlements within the 20-km zone averted effective doses to adults of up to about 50 mSv and absorbed doses to the thyroid of 1-year-old infants of up to about 750 mGy (see tables C11 and C12 of appendix C).”[IV-D-3.104] In other words, despite the problems with the evacuation, they estimate that thyroid doses of infants would have been as much as about 10 times higher otherwise. –Higher doses in the “south trace”: “The deposition of radionuclides on the ground at locations within the south trace (the towns of Tomioka, Naraha and Hirono and Iwaki City of Fukushima Prefecture) was significantly enhanced in 132Te, 131I and 132I compared with the rest of Japan. As a consequence, for the assessment for the non- evacuated areas, the external exposure per unit deposition density of 137Cs in the first year was larger by a factor of about two for Iwaki City than in the rest of Japan, as shown in figure C-IX.” [AppendixC C83] This finding will probably spark some debate. The relatively high deposition of these nuclides in this zone, and their different ratios, have been known for some time; nevertheless some will debate how correct the model is in estimating resulting doses twice those of elsewhere. Not enough actual dose measurements were taken in a timely manner to conclude one way or another. — Likely overestimation of thyroid doses: The assumptions relating to protective measures in most cases assumed greater exposure, and are generally consistent with those given by the Japanese gov’t. But they note, “The Committeeʼs estimates of settlement-average absorbed doses to the thyroid from internal exposure were up to about five times higher than the corresponding values derived from direct monitoring of this group” [IV-F-1.117]. Again, not enough direct monitoring was done, but the thyroid doses given are probably overestimates, though within an order of magnitude of available in-vivo monitoring. –Comparison with WHO estimates: UNSCEAR’s results are based on “more realistic assumptions and more comprehensive and recent data, particularly for the evacuated areas.” Both sets of estimates are generally consistent, though some WHO estimates for evacuated districts were higher, and “there are also locations where the estimated doses in this study were higher than those in the WHO study. “[IV-F-2.119][Appendix C144-145] –Most external doses already below 1mSv/yr: “The annual external doses to adults are already substantially below the Japanese criteria for evacuation (20 mSv). Decontamination of settlements with techniques that from past experience reduce the doses by about 1.5 would further reduce external doses for all the population groups [I1, U3]. The results in table C19 indicate that, after March 2014, the settlement-average effective doses to adults from external exposure were estimated to be less than 1 mSv in a year in seven of the evacuated localities.” [Appendix C136] This is very important to note, and needs to be independently verified. ++++++++++++++
  • COLLECTIVE DOSES The issue of whether or not to include collective dose estimates was also reportedly the subject of heated debate within the committee.
  • 7. Ultimately collective effective doses and collective absorbed doses to the thyroid for the Japanese public were described [IV-D-3.107] [Table 8]. ++++++
  • Collective effective dose (in man-sieverts): 1st yr: 18,000 after 10 yrs: 36,000 after 80 years: 48,000 ++++++ COMMENT: They note that this is “approximately 10-15% of the corresponding value for European populations exposed to radiation following the Chernobyl accident. Correspondingly, the collective absorbed dose to the thyroid was approximately 5% of that due to the Chernobyl accident.” [IV-D-3.108]. This seems reasonable, based on what is known about source terms and deposition, even taking uncertainties into account. Additionally, Ian Fairlie, a nuclear critic who has been lobbying strongly for the continued use of collective dose estimates, compared UNSCEAR’s estimates and his own, and remarked that those in the report are slightly higher than in the draft UNSCEAR report in November 2013, and are so close to his own that “the agreement is slightly unnerving!”
  • http://www.ianfairlie.org/news/new-unscear-report-on-fukushima-collective-doses/
  • Nevertheless, the report states that “The collective dose to the general public is an instrument primarily for optimization of protection or comparing radiological technologies or protection measures. The aggregation of very low individual doses over extended time periods is inappropriate” [Appendix C69]. In other words, UNSCEAR does not take the further step of estimating additional cancers from the very low doses, though it is easy to do so based on LNT. Fairlie’s preliminary estimate is that approximately 5000 additional deaths from cancer will occur in Japan in the future (i.e., over 80 years). It’s a bit odd that collective dose estimates are provided but their use for risk estimates discounted; this is a compromise that resulted from internal disagreement, and ends up sending a mixed message. +++++++
  • DOSES IN OTHER COUNTRIES The committee did not do its own detailed study of doses to populations outside Japan, but relied on a review of published estimates, including those by WHO, and assessments carried out by Member States. They conclude that the “average effective doses to populations living outside Japan due to the accident were less than 0.01 mSv in the first year.” [Appendix C-III-C.1-2 ] [Table C15] +++++++
  • DOSES TO WORKERS: This is dealt with extensively in Annex A, Chp V, and in Appendix D. COMMENT: The findings will not be summarized here. But it is important to note that UNSCEAR reviewed and evaluated TEPCO’s monitoring and dosimetry, and conducted independent assessments of doses due to internal exposure for defined groups of workers, and compared the results made with the doses reported in Japan for these workers. They judged that in general, methods and systems for assessing internal exposures were adequate and the data reliable. For external exposures, their acceptance of TEPCO data was qualified because of widespread sharing of dosimeters during the first weeks and other problems. The committee was unable to get info on dosimeters used, etc., from emergency service workers such as policemen, fire-fighters, and Self-Defense Force personnel. [V-E] In addition, “the reliability of assessments reported by TEPCO for those of its workers for whom 131I was not detected in the body could not be confirmed. Neither of the methods available to estimate 131I intake in these circumstances provided a reliable estimate of true intake, and the resulting internal exposure estimates could have been subject to a high degree of uncertainty.” [V-F.155] Also, “Evidence from this investigation indicates that estimates of dose due to internal exposure reported by contractors for their workers were less than about 50% of those of the Committee for eight cases out of the nineteen where a comparison could be made. For the other eleven cases, the Committeeʼs dose estimates were broadly in agreement with those of TEPCOʼs initial alternative assessments (which were not normally reported). Based on the comparative assessments carried out, the Committee was unable to confirm the reliability of the internal exposure assessments reported by contractors for their workers.” [V-F.155] Claims that UNSCEAR uncritically accepted TEPCO data on worker doses are inaccurate. +++++++++++++ HEALTH IMPLICATIONS: These are dealt with extensively in Annex A Chp VI, and Appendix D and E. Solid cancers, specifically thyroid cancer, and breast cancer, as well as leukemia and prenatal exposure issues all have separate sections. The general appraisal states, “No discernible increased incidence of radiation-related health effects are expected among exposed members of the public or their descendants.” [III-3.39] As described in more detail below, this is not a claim that no disease will occur.
  • COMMENT: Taken as a whole, the report’s dose estimates for the public can be said to err on the side of overestimation, and no data has emerged yet that suggests gross underestimation of the doses themselves. The range of variability — from 30%-50% of the average estimates to 2 or 3 times more in some cases — has been clearly noted, along with other uncertainties. They state that, “in some cases sizeable population groups may have been exposed to doses at the higher end of this distribution.” [VI-A-158] The health implications in the report are based on widely accepted radiation risk assessment principles, specifically the WHO’s risk assessment models, including the abandonment of DDREF and the effective doubling of assumed fatal cancer risk from 5% per Sv to 10%. The highest projected average lifetime doses are for 1 year olds living in “Group 2” zones (unevacuated areas of Fukushima prefecture), who could receive an estimated average 18mSv effective dose by the time they are 80 years old. Adults in the same zone may receive an average of 11mSv. The noted variability suggests these could be as much as 60 mSv and 30 mSv respectively in some cases. Thyroid exposures may be as high as 150 mSv. Evaluating the potential health implications of this primarily means looking at what is known about disease risk at these exposures, and estimating the sizes of the cohorts at the high end of the exposure range and so at greatest risk. Valid questions about the report’s conclusions would seem to be primarily related to public health issues. While leukemia and other
  • 8. malignancies and illnesses show different correlations with radiation exposure, the maximum expected 60 mSv lifetime exposure would suggest an additional 0.6% risk of fatal cancer to those individuals. UNSCEAR, like many, myself included, feels comfortable in calling this a “low” extra risk. As Fairlie points out, though, if collective dose assumptions are true, this works out to about 5000 people in Japan as a whole. Even if this will not be detectable directly or epidemiologically, it’s important to discuss what steps if any should be taken about it. The same holds true for other potential illnesses. [The UNSCEAR contact stressed that the purpose of the committee was to examine the radiological consequences of the Fukushima accident, and while it was important to debate current assumptions concerning radiation risks, it was not intended to be a process for revising these. It’s widely recognized within the agency and elsewhere that there are good reasons for revising and updating the risk assessment guidelines laid out in UNSCEAR 2006, and actual work on a wide-ranging review will begin soon. Among the items being considered for discussion and possible revision are low-dose issues in general, including LNT; DDREF; how age and gender affect risk; thyroid exposures and the role of stable iodine. We’ll note that these are all extremely contentious issues and have been the source of much disagreement and dissatisfaction in the context of Fukushima.] +++++++++
  • THYROID CANCER: In particular, the report notes, “An increased risk of thyroid cancer in particular can be inferred for infants and children. The number of infants that may have received thyroid doses of 100 mGy is not known with confidence; cases exceeding the norm are estimated by model calculations only, and in practice they are difficult to verify by measurement. “[III-3.40] Thyroid doses and results of the Fukushima Prefectural Health Survey (FPHS) are discussed in some detail in [VI-B-3] and [Appendix E, sec. D] , and in [III-3.42], they state, “Data from similar screening protocols in areas not affected by the accident imply that the apparent increased rates of detection among children in Fukushima Prefecture are unrelated to radiation exposure.”
  • COMMENT: The interpretation of the Fukushima Prefectural Health Survey thyroid screening results has been controversial, and the UNSCEAR report uses data that was available by the end of July 2013, at which point about 175,000 children living in Fukushima Prefecture had received thyroid examinations and 13 cases of thyroid cancer had been detected; the number of cases as of April 2014 is 74. The report’s conclusions nonetheless are supported by most recent expert opinion. The report also states that an increase in radiation-induced thyroid cancer may occur in coming years, while noting that the dose ranges in general, as shown by its own estimates and by in-vivo results, are much lower than in the Chernobyl area, and in most districts lower than has previously been associated with radiogenic thyroid cancer incidence. Appendix E, section D, gives the most detailed treatment of thyroid cancer issues. “It considered that fewer than a thousand children might have received absorbed doses to the thyroid that exceeded 100 mGy and ranged up to about 150 mGy. The risk of thyroid cancer for this group could be expected to be increased. However, it would be difficult, if not impossible, to identify precisely those individuals with the highest exposure, and risks at these low doses have not been convincingly demonstrated; moreover, as noted above, the lower dose values suggested by direct thyroid measurements on some populations should be reviewed, as well as their associated uncertainties.” [Appendix E33] “The increased prevalence of thyroid cancer [found in the health survey screening] may reflect the identification of previously undetected disease with these improved diagnostic techniques and increased screening rates, rather than a true increase in the prevalence of thyroid cancer [J8]. The prevalence of clinically occult small papillary thyroid cancers (i.e. asymptomatic tumours that would remain latent, but detectable) could be as high as 35% in many parts of the world, according to findings from autopsies of young people from the general population [R4]. A fraction of these would be detected by any ultrasound screening programme.”[Appendix E48] COMMENT: This explanation is fully consistent with expert consensus, including that of several who can be considered nuclear critics. Virtually all leading experts who have given an opinion also expect some increase in radiation-induced thyroid cancer to emerge in coming years, but expect it to be small. Some people feel that the report overemphasizes (and confusingly cites) data which indicates that the normal prevalence of clinically occult small papillary thyroid cancers in young people (without radiation exposure) as 35%. The rates found at autopsy in adults are known to be this high or higher, and few autopsy studies of children have been done. It should also be noted that the report is not stating this rate as a certainty, but says “could be as high as 35%.” This is accurate. In summary, thyroid cancer remains the greatest expected risk to exposed populations, while aggregate risks from very low doses as indicated by collective dose estimates are not examined by UNSCEAR and deserve to be. ++++++
  • LEUKEMIA: This risk is assessed primarily on bone-marrow doses. The report estimates settlement or district-average bone-marrow doses of up to 10mGy in the first year for infants in both evacuated and unevacuated areas. These are expected to add 0.0011 – 0.0085 % to the lifetime risk of leukaemia. The committee concludes that “any increase in childhood leukaemia is not expected to be discernible.” [VI-B-2.176] It’s worth noting that a large-scale epidemiological study by Cardis et al detected a correlation between increased leukemia rates and worker exposures of approx 20 mSv. ++++++
  • BREAST CANCER: “The Committee estimated settlement-average absorbed doses to the breast of girls before and during the evacuation to be less than 10 mGy.” This works out to 0.03% added risk; possibly 0.09 – 0.15% with childhood exposure. “The Committee does not expect that any radiation-induced increase in breast cancer incidence will be discernible.” [VI-B-2.177] +++++++++
  • PRENATAL EXPOSURE They note that “absorbed doses in utero of about 10 mGy may lead to an increased incidence of cancer during childhood, especially of leukaemia (with a relative risk of 1.4) [U7]. It cannot be excluded that a small number of pregnant women had absorbed doses to the uterus of about 20 mGy, perhaps doubling the risk of leukaemia for their unborn children. However, the number of pregnant women involved was relatively small and childhood cancer is a rare disease. Thus it is expected that any increase of the risk would not lead to a discernible
  • 9. increase in the incidence of childhood leukaemia or other childhood cancers.” [VI-B-2.178] [Appendix E37] That is to say, an increase in childhood leukemia due to in-utero exposure is possible but will be difficult to detect because the numbers will be very small. Also, they state that, “The prenatal exposure resulting from the accident at FDNPS is not expected to increase the incidence of spontaneous abortion, miscarriages, perinatal mortality, congenital effects or cognitive impairment. ” [VI-B-2.178] [Appendix E37] This is an area that is under-studied, and more references are needed. The existing Fukushima Pref. Pregnancy and Birth Study is neither detailed nor extensive enough to make these conclusions. +++++++++++
  • SOURCES OF INFORMATION: –A long list of agencies and organizations who provided data is given in Annex A, Chp II (p.95-107). Primary sources are predominately Japan gov’t agencies, other member states (like US DOE), TEPCO, and international intergovernmental organizations (WHO, CBTO, IAEA, FAO, WMO). Secondary sources include several NGO’s, including CRIIRAD (close partner of CRMS), ACRO, Greenpeace, Union of Concerned Scientists (UCS), and SAFECAST (They did not contact us before accessing our data, which is fine with us because it’s open. After we heard about it, though, we emailed them and offered to answer any questions they had. They sent us an appreciative reply but had no further inquiries). In addition, the committee made use of hundreds of peer-reviewed studies, most of which can be considered independent. Most of the raw data will be made available in electronic form online and on CD-ROM; at the time of this writing its release has been delayed while copyright issues are worked out, but it’s expected to become available in May 2014. UNSCEAR’s mandate requires them to obtain and evaluate data from member states, and their internal policy is to locate and use independent data to verify official data wherever possible. They used SAFECAST data, for instance, to cross-check Japanese govt environmental radiation data. In fact, it’s clear that they prefer to have many independent sources of information, but these were really only adequate for environmental measurements. There’s just not nearly as much independent data available for health, food, biota, etc., but they still located what they could and include comparisons. They make a point of noting several times that they felt they could not rely on the data TEPCO provided concerning the exposures of workers without verifying it, and that this was not always possible adequately; they did what they could to evaluate the dosimeters being used, and actually uncovered evidence that led to higher estimates being given for a number of workers. Similarly, for workers’ internal contamination, they state, “Evidence from this investigation indicated that many of the dose estimates reported by contractors for their workers may have been significant underestimates. Based on the comparative assessments carried out, the Committee was therefore unable to confirm the reliability of assessments reported by contractors for their workers.” [sec D67, p. 244] UNSCEAR is also mandated to review and comment upon the WHO reports, but not required to agree with them. In the current report, they point out the general consistency between their findings, while also noting the differences and the reasons for them (in dose estimates for instance [Chp IV-2, p62]). Similarly, the WHO and UNSCEAR reports will be reviewed by the IAEA as it formulates its own report this year. Each successive review body has access to newer information so ideally the uncertainties will decrease with time, while at the same time studies and datasets which are repeatedly cited and accepted by consensus become harder to challenge. Lastly, the report makes it clear that there are quite a few things which will require continuous monitoring and updates, including the thyroid problems, the ongoing water releases, food safety, and the effectiveness of decontamination, and that they intend to issue periodic updates. ++++++++++++++++
  • ASSUMPTIONS: Risk, and “discernible” effects: The report goes to great pains to describe the concepts of risk it uses, and what it means when it refers to “discernible” effects. They point out that unlike direct, immediate or acute radiation effects, whose cause can be directly observed and determined, in the case of “stochastic” effects, usually from long-term, low dose exposures, we can never be certain if they were caused by radiation. At present we can infer it statistically when incidence of a disease increases after a population group has been exposed to radiation, and hopefully in the future reliable biomarkers will be discovered that will tell us with more certainty [VI-A.164, 167]. This passage [Annex A Chp IV-A.162] explains what they mean when they say “no discernible increase”: 167. “In this chapter, the Committee has estimated values of the risk due to exposure for members of various exposed groups. Where the estimated risk of the disease is sufficiently large in a large enough population, compared to the normal statistical variability in the baseline incidence of the disease in that population, an increased incidence due to irradiation may be “discernible” in disease statistics and epidemiological studies. Conversely, when risks may be inferred on the basis of existing knowledge, but the level of inferred risk is low and/ or the number of people exposed is small, the Committee has used the phrase “no discernible increase” to express the idea that currently available methods would most likely not be able to demonstrate an increased incidence in the future disease statistics due to irradiation. This does not equate to absence of risk or rule out the possibility of excess cases of disease due to irradiation, nor to the possibility of detection of a biomarker for certain types of cancer in certain subgroups being identified in the future that can be associated with radiation exposure; moreover, it is not intended to disregard the suffering associated with any such cases should they occur.” When they use the phrase “no discernible increase,” they mean risks might exist, but: –Any increase will be within the bounds of normal variation of the disease without radiation. –Risks can be inferred theoretically but not directly detected with current science or statistically. –Compared to normal occurrence of the disease, the risk is relatively small. –The group of people affected is too small to make a meaningful statistical analysis. –They’re not saying they don’t care about the people who are affected, however few they might be. COMMENT: We’re right to scrutinize whether they’re using adequate statistical tools to detect small increases, whether they’re making adequate use of recent epidemiological and pathological research, and to ask that a better consensus be reached about what constitutes a “low” risk or a “small” number of people. An underlying problem is that radiation evaluation and oversight agencies like UNSCEAR tend to demand overwhelming proof that a disease risk exists before taking steps to guard against it (while critics often tend to accept a single study as sufficient evidence of danger). The language UNSCEAR uses is precise but still easy to misinterpret, and will be spun by nuclear advocates to mean “no problems,” and criticized by opponents because the advocates will be able to spin it this way. [The UNSCEAR contact said simply that the agency and committee members prefer to base evaluations on strong empirical science. And
  • 10. the report itself is less of a formal risk assessment than an examination of the evidence which can be used to gain insight on and to comment on risks. The distinction is not merely semantic: though very carefully researched and put together, the report is intended as a scientific commentary and should be taken as such.] Other assumptions: Most of these assumptions tend to raise the estimated doses and estimated health risks. –Includes risks from doses under 100mSv: The report states that there is little or no direct evidence for an overall increase in cancer after effective doses of 100 mSv or less, but uses of LNT to infer that the risks exist and to estimate them. It goes on to say that these inferred risks “…are so small that in general no discernible radiation-related increase of overall cancer incidence would be expected among exposed members of the general public,” but notes that exceptions exist for certain types of cancer risks in certain groups. [Appendix E28] [As noted above, the report does not “clearly endorse” LNT, but the committee compromised by using it while not fully endorsing it. It’s a regrettable mixed message.] UNSCEAR includes below 100 mSv risks in its dose estimates, specifically for acute exposures [VI-B.2.171] and by implication for long-term exposures [APPENDIX EII.B(b)]. In particular, they accept that “for a population incurring an acute exposure of 100 mSv, the lifetime risk of cancer would increase from about 41% to about 42%. For 10 mSv, the theoretical increase would be from about 41% to 41.1%..” [Appendix E8]. Basically, they’re saying that a 0.1% or 1% increase in risk theoretically exists at these exposure levels, but we won’t be able to detect the increased disease these might cause. –DDREF=1 . As described briefly above, a “dose-and-dose-rate effectiveness factor” or DDREF has usually been used when dealing with doses received over time, based on evidence that these are less damaging overall than acute doses, delivered all at once. The idea has been widely but not universally accepted, and previous guidelines have often used DDREF=2.0, that is, long-term doses were expected to be only half as damaging as acute ones; occasionally other DDREF values, such as 1.5, have been used. This was reportedly the subject of extensive debate in the UNSCEAR committee, and interestingly there is only one reference to DDREF in the entire report, which gives lukewarm endorsement to the WHO’s use of DDREF =1 for longterm doses. [APPENDIX EII.B(b)] [The UNSCEAR contact confirmed that this is the result of a compromise, and that the report justifies the use of DDREF=1 because of WHO’s precedent.] — 10% added lifetime cancer risk per Sv: Because DDREF=2 has commonly been applied to longterm dose estimates, the result has been an assumption that the added lifetime risk of fatal solid cancers is 5% per Sv exposure. In this report, UNSCEAR effectively doubles that risk to 10% per Sv. As noted in [APPENDIX E8], this means an exposure of 100 mSv, even delivered over time, is assumed to raise lifetime fatal cancer risk by 1% (instead of 0.5% as previously), and a 10mSv exposure by 0.1% (instead of 0.05%). Some will argue that the risks should be assumed to be even higher, but this doubling of the previous assumption is an important step and was only agreed to after a long fight. — A lifetime is 80 years: For lifetime doses, the report uses an integration period of 80 years, instead of 70, because of longer Japanese lifespans. [Appendix C2]. This is also a good idea and a step forward. –Estimates are based on both adult and child models: Dose estimates used both the standard ICRP adult “computational phantom” model and voxel phantom models for other age groups [AppendixC40]. Also, largely because of how the “effective dose” standard was developed and how it is intended to be used, specifically because it averages over all ages and both sexes, in order to better estimate effects on other age groups the estimates of risk from exposure during childhood in the report are based instead on estimates of absorbed doses to specific organs [Appendix E26]. The previously released 2013 report (VOLUME II: Scientific findings on effects of radiation exposure of children Annex B: Effects of radiation exposure of children) goes into more detail about improvements made in determining health effects in children. Some critics claim that radiation health effects models are based only on data for adults, and so are wildly inaccurate concerning children, but this has not really been true for long time. The entire notion of “dose” is currently being debated, because it has been pressed into a number of uses for which it was not originally intended, and is widely thought to be inappropriate for clearly communicating risk to the public. –Assumes no benefit from potassium iodide: UNSCEAR could not determine exactly who among the public received potassium iodide (KI) and when, so in their calculations they assumed that no-one did. [IV-3.77.] –Uses the lowest shielding factor from buildings: While they considered a number of different types of building (and hence degrees of shielding) and different amounts of time spent indoors,” because in Fukushima Prefecture and nearby prefectures, the majority of people live in wooden houses, the dose estimates were based on people living in wooden houses [ IV-C.81]. This means that doses for people living in concrete houses or multistory buildings, which provide greater shielding, will be overestimated; this will mostly apply to populations in Fukushima City and Koriyama City. — Assumes no benefit from remediation: “Detailed information about the scale and efficiency of the implemented land remediation actions was not available at the time of this assessment, and thus the Committee did not take into account the possible reduction in exposure levels due to any remedial measures.” [IV-3.78.] That is, dose estimates assumed no remediation had been done, so doses in many areas are probably overestimated. — Doses from inhaling resuspended particles, etc. are insignificant: “Other possible exposure pathways, such as the inhalation of resuspended radionuclides or exposure via contamination of the skin, were not major contributors to exposure for the releases from FDNPS and were not considered further.” [Appendx C6] This may in fact be true, but it would be better to include these, along with a discussion of the kinds of situations that could make these exposures more significant. –Direct doses from seafloor sand and sediment are insignificant: They did not include possible exposures from offshore sediment or sand, reasoning that these would only be relevant outside the 20km evacuation zone, where they would contribute only small exposures, whereas within 20km access is restricted. Access has been relaxed in many areas closer to the NPP, however, so more care should probably have been taken to determine potential exposures, particularly in coming years.[Appendix C7] –Psycho-social effects are not covered in detail: Appendix E notes that “…an increase in the incidence of psychological effects has already been observed among the general population after the FDNPS accident [Y4, Y5]. Such long-term psychological effects can be expected to occur in the population of Fukushima
  • 11. Prefecture.” Also, [VI.A.163] notes the importance of mental health issues, and explains that they examined this even though, “Evaluating such effects is not part of the Committeeʼs mandate.” Psychological and mental health issues are already quite serious in Fukushima and elsewhere, and do not receive nearly as much attention as they should. We’re left to wonder who does have the mandate to evaluate mental health issues after nuclear disasters. [The UNSCEAR contact said that this is clearly within the mandate of WHO.] ++++++++++++
  • DOSES FROM FOOD: COMMENT: Internal exposures from ingestion were estimated by modeling based on official food contamination databases. These are primarily those provided by the Japanese MHLW and MAFF, which form the basis of an FAO/IAEA food database which includes over 500 types of foodstuffs sampled in all 47 prefectures. To my knowledge, the FAO/IAEA database has never been publicly accessible, though the report says it will be included as an electronic attachment (attachment C-8). The report notes that measurements of food actually consumed by families indicate much lower levels of internal contamination from food than their modeling suggests, as do WBC measurements, but they considered their approach appropriate, because, “The measurements covered only a limited number of people and locations, and were insufficient to estimate directly the internal exposure of people in either Fukushima Prefecture or the rest of Japan. Therefore the Committeeʼs estimates of internal exposure were based on measurements of radioactive material in the environment, combined with models describing how people were exposed to this material.” [IV-B.67] [Appendix C9, C124, C143]. Nevertheless they used these in-vivo data to check the validity of their assessments. –UNSCEAR most likely would have looked at other independent food contamination data had extensive datasets been available. According to the director of CRMS, which could have provided the most relevant data, they were approached at one point by UNSCEAR but declined to cooperate. Their food testing database was publicly accessible, however. Nevertheless, efforts like the independent “Minna no data” food database project could be important in coming years for providing an independent cross-check. –The data used was for marketed foods, meaning the basic assumption was that food in excess of prescribed limits (i.e. 100 Bq/kg since early 2012) was not eaten. [IV-B.73] [Appendix C60] This seems more realistic than the WHO’s assumption that all contaminated food found was eaten. UNSCEAR assumed that any food item that was below detection limits had 10 Bq/kg [Appendix C24]. This will probably result in overestimates. –On the other hand, they note, “If individuals living in the areas of higher deposition density had eaten locally produced food even though restrictions had been introduced following the accident, then they could have received exposures significantly higher than those presented here.”[Appendix C125] Similarly, they acknowledge that food restrictions took time to come into effect, and that “an adult living in Iitate Village and eating only locally produced vegetables could have received an additional effective dose of about 10 mSv in the first week following the accident.” They note, however, that, “This assumption is unlikely given the time of year and the limited availability of green vegetables growing in the open, but cannot be excluded as a possibility.” [Appendix C128] This agrees with independent assessments by Imanaka and others. –Also, they recognize that some people might be ignoring warnings against eating wild mushrooms and other plants, or eating wild game. “Such food habits have the potential to increase the estimates of effective dose from ingestion for these individuals by up to perhaps a factor of 10, however there is no evidence of such higher doses in the extensive sets of in vivo whole body measurements of the general public.” [IV-B.101] This is probably a misstatement; a number of such cases have been reported, and there is not enough WBC dosimetry from spring and summer 2011 to say with confidence. –They acknowledge that most people in Japan get their food from supermarkets, but still assumed for their estimates that 100% of the food consumed in Fukushima is local (and has at least 10Bq/kg of Cs). They note that if only 25% of a person’s food was from the local prefecture then their estimated doses would be about three times lower than the estimates [Appendix C124]. –For estimating exposures beyond the first year from eating seafood, “the results of modeling the dispersion of radionuclides in the sea off Fukushima Prefecture by Nakano and Povinec [N3] were used.” [IV-B.73] –Their future dose projections from ingestion assume that food monitoring and restrictions will continue [Appendix C131]. Good if this turns out to be true, but I think it would be important have an alternate set of estimates that shows what would happen if monitoring and restrictions stopped. +++++++++++ MODELING For most of the dose estimates, they depended on ground deposition measurements (mainly derived from ground sampling), using ATDM (Atmospheric Transport and Dispersion Modeling) where necessary to derive air concentrations, as opposed to in-vivo data like WBC, of which they judged not enough was available to make firm conclusions [IV-B.67]. In most cases it was possible to check deposition density and atmospheric models against each other. The problem was the lack of sufficient measurements of almost any type during the first few weeks, which made it necessary to use inverse modeling based on later measurements. They looked at the available ground deposition data, found the source term and ATDM models which best fit the actual deposition, and then used those to fill in the missing data. It’s a model, and as George E.P. Box famously said, “All models are wrong, but some are useful.” In this case, the results seem to generally err on the side of overestimation. The report says: [IV-B.70] “Because measurements of concentrations of radionuclides in the air were insufficient for its assessment, the Committee had to estimate values. Such estimates were also obtained from the source term and simulating the transport of radioactive material through the atmosphere using ATDM. However, these estimates have large uncertainties at specific times and locations, not only because of incomplete knowledge about the quantities of radionuclides released and how these varied over time and location, but also because of uncertainties in the models used to simulate the subsequent dispersion of the released material in the atmosphere. In view of these uncertainties, the Committee chose to use the measurements of deposition density to adjust the estimates of concentrations in the air from the ATDM analysis.”
  • COMMENT: Because there have been a number of separate estimates of the source term, which might be considered fairly close (“For 131I the estimates ranged from about 100 to 500 PBq; for 137Cs they ranged, in general, from about 6 to 20 PBq” [Appendix B12]), they evaluated all of them and eventually selected the one by Terada et al. [Appendix B15]. They acknowledge that it lies at the lower end of the estimates
  • 12. they considered (a very complete list of 16 studies is given in Table B2), and may underestimate the total releases by a factor of about 2, but they felt it fit best with measured observations for deposition on land and so was the most useful for use in estimating doses to people [Appendix B16]. Again, they were primarily looking at Cs134, Cs137, and I131, but included other isotopes of iodine and cesium, Te132, and Xe133, in the source term and hence in dose estimates [Appendix B17]. In addition, they say, “The fractional release and significance of isotopes of elements such as strontium, barium and plutonium was much lower than those of iodine and caesium because of their much lower volatilities; this has been confirmed by measurements in the environment [N18]32.” [Appendix B18]. This does not mean they ignored these, but that they calculated that ultimately they contributed very little to the doses people have gotten and are likely to get in the future. I think it would have been better to include a fuller treatment of these isotopes in relation to each dose category. [The UNSCEAR contact explained that actual release quantities were used as intermediate values, to help determine the relative ratios of nuclides that were released; assessments of nuclide levels in the environment were based on actual deposition measurements wherever possible.] Some things to keep in mind are that
  • 1) They felt there were not enough in-vivo dose measurements available to use as a basis for estimating doses to the entire affected population;
  • 2) There were also not enough direct measurements of concentrations in the air, especially during the first few weeks, to make good estimates; 3) the resulting model ends up being very complex, but does not appear to underestimate doses overall; 4) the estimated doses this results in, both external and internal, are much higher in most cases than what the in-vivo monitoring has shown (more on this below). For releases to the ocean, they also looked at a number of estimates, mainly summarized in Table B6. They preferred to use estimates based on three-dimensional modeling [Appendix B30]. They conclude that: “…the direct release to the ocean of 137Cs was likely to have been in the range of about 3–6 PBq, with the direct release of 131I likely to be about three times higher. The direct release of 90Sr could be estimated to be in the range of about 0.04–1 PBq (based on ratios to the 137Cs release). The estimated direct releases of 137Cs (about 3-6 PBq) were of a similar order of magnitude to the estimated deposition on to the ocean from releases to the atmosphere (about 5–8 PBq)” [Appendix B30]. We should point out that while there’s a wide range of ocean deposition estimates, and a fair amount of relevant data was released after this report’s Sept. 2012 cutoff date, Aoyama gives 15PBq as his estimate of deposition from the atmosphere to the ocean, and Bussesler has said that the estimates for direct releases to the ocean are converging at 15-30 PBq. UNSCEAR’s estimates — 3-6 PBq direct, 5-8 PBq atmosphere to ocean — are on the low end. [The UNSCEAR contact explained that due to the way they were using the release data for both atmosphere and ocean, the actual release values were less important than how they helped clarify the relative mix and movement of nuclides] (APPENDIX B. RADIONUCLIDE RELEASES, DISPERSION AND DEPOSITION describes the modeling, its assumptions and uncertainties, in detail.) +++++++
  • NON-HUMAN BIOTA: This is dealt with in detail in APPENDIX F. ASSESSMENT OF DOSES AND EFFECTS FOR NON-HUMAN BIOTA and also in Annex A: VII. ASSESSMENT OF DOSES AND EFFECTS FOR NON-HUMAN BIOTA This is worth discussing further, but basically the report bases its assessments on models and a limited number of field measurements. The assumption seems to be that large-scale damage to populations, including die-offs, present a unacceptable level of effect, and effects below this should be noted but are of less concern. This entire way of thinking should be re-evaluated. It should also be noted that some in the committee reportedly felt that too much time and resources were devoted to examining non-human effects, i.e. “birds and bunnies.” “For the late phase after the accident, a potential risk of effects on individuals of certain species, especially mammals, may exist in areas of relatively high deposition density but observable population effects for terrestrial biota are considered unlikely. Nonetheless, changes in biomarkers of various types cannot be ruled out, especially in mammals [G5], and such effects may persist in the late phase for areas of highest deposition density.” [VII-A-196] “A few field studies have reported effects in areas affected by FDNPS releases, such as decreases in bird and insect populations [M22, M23] and morphological and genetic disturbances in butterflies [H6]. The relationship between exposure and effect has not been unequivocally established in these studies. Furthermore, the observations are not consistent with the Committeeʼs assessment and suggest that further analysis is needed to establish whether radiation exposure was an important factor, among many others, including the impact of the tsunami itself, in causing the environmental effects observed.” [VII-A-197] In particular, this refer to studies on butterflies by Hiyama, Otaki et al, and on birds by Moller, Mousseau, et al. Basically the report is saying that the effects observed in these studies do not match results predicted by the models UNSCEAR uses (primarily the ERICA Assessment Tool, jointly developed by several European agencies) or other cited studies, such as those by Garnier-Laplace et al. [Appendix F3] The reality is that not many studies have been done concerning non-human biota in radioactive fallout zones, so the body of data to draw on is fairly sparse. It’s a bit of a Catch-22 for these researchers, as funding is difficult to obtain and so not many studies are done, meaning it is usually difficult to demonstrate the importance of doing more studies. The report summarizes as follows: “The doses and associated effects of radiation on non-human-biota following the accident were evaluated by comparing with the Committeeʼs generic evaluations of such effects that were conducted before the accident. Exposures of both marine and terrestrial non- human biota following the accident were, in general, too low for acute effects to be observed, though there may have been some exceptions because of local variability. In general: (a) Effects on non-human biota in the marine environment would be confined to areas close to where highly radioactive water was released into the ocean; (b) Continued changes in biomarkers for certain terrestrial organisms, in particular mammals, cannot be ruled out but their significance for population integrity is unclear. Any radiation effects would be constrained to a limited area where the deposition density of radioactive material was greatest; beyond this area, the potential for effects on biota is insignificant.” [VIII-E- 229] Again, these conclusions can basically be considered sound, especially since they do not rule out greater damage. But it’s worth examining the underlying assumptions about what would or would not be significant in terms of effects to other species, and to think about how radioecology can be improved. [The UNSCEAR contact pointed out that there have been and will continue to be quite a few ecological and environmental effects that we should be concerned about that are not directly due to radiation — changes in habitat due to abandonment of land, changing balances of
  • 13. species, etc — but which are not part of UNSCEAR’s purview. These actually fall under UNEP (United Nations Environment Programme), but relatively little has been done so far; the Japanese side will need to initiate more action on this. Interestingly, UNSCEAR is technically part of UNEP.] +++++++++++
  • UNCERTAINTIES The report describes and discusses quite a few areas of uncertainty, their causes, and implications. These are touched on throughout the report, and dealt with in detail in Appendix C, Chp IV, and summarized in AnnexA Chp IV-E.] [According to the UNSCEAR contact, the available data did not generally allow an actual uncertainty analysis, so statements about uncertainty are the result of sensitivity analyses instead. The uncertainties will continue to be revisited and reevaluated in the future.] Some of the more important ones include: –“The uncertainties associated with individual measurements of 137Cs and 134Cs were relatively small, but those for 131I were larger because of the significant amount of radioactive decay that occurred before the measurements were made. ….
  • For Fukushima Prefecture, there were extensive measurements with adequate spatial coverage, and the district-average doses estimated for specific districts were considered to be accurate within a factor of two. For the Group 4 prefectures, there were comparatively fewer measurements, and the uncertainties in the prefecture-average doses were likely to be larger.” [IV-E.111] –“Another source of uncertainty stemmed from the incomplete knowledge of the release rates of radionuclides over time and the weather conditions during the releases. …The settlement-average effective doses and absorbed doses to organs for these population groups may be over- or underestimated by a factor of up to typically four to five because of uncertainties in the ATDM results for specific locations and times.” [IV-E.112] –“There was an uncertainty associated with the doses derived from the measurements of radionuclides in foodstuffs (appendix C), and this was difficult to quantify….Foodstuffs were not sampled randomly, because the authorities gave priority to identifying foods with the highest concentrations. It was therefore likely that the values of average concentrations used by the Committee were overestimates, particularly for the first months after the accident when there were relatively few measurements. Many measurement results were less than the detection limits and were assumed by the Committee to have a fixed value at the detection limit; this also led to some overestimation of the doses to people due to ingestion. Changes in the pattern of food distribution and consumption were another source of uncertainty. If it had been assumed that only 25% of food consumed in Fukushima Prefecture was from the prefecture, then the estimated effective doses from ingestion for the first year would have been 30% of the Committeeʼs estimates.” [IV-E.114] –“The Japanese diet is relatively high in stable iodine. This could have resulted ihttp://www.slideshare.net/safecast/unscear-2013-fukushima-final-report-commentary-ownloadn less transfer of radioiodine to the thyroid than implied by the standard model, and thus in slightly lower doses from this source. However the overall effect would have been small when compared to other uncertainties associated with the dose assessment (see appendix C).” [IV-E.115] –“The estimates of exposure of the communities evacuated in March were based on the source term and NOAA–GDAS ATDM results directly. The agreement between the NOAA–GDAS ATDM results and the measured data for the deposition density of 137Cs is good for many areas but for some locations, the ATDM results under- or overestimated the levels by up to a factor of ten. On average, the district- average deposition densities of 137Cs obtained from NOAA–GDAS ATDM are about a factor of two higher than the values from the MEXT surveys. For 131I, the district-average values obtained from NOAA–GDAS ATDM range from overestimates by up to a factor of two, to underestimates by up to a factor of 10, with an average of about one.” [Appendix C117] –“A source of uncertainty in the estimation of doses to evacuees from inhalation derives from incomplete knowledge about the release rates of radionuclides over time and the weather conditions during the releases.” [Appendix C118] –“The Committeeʼs estimates of doses beyond the first year from ingestion were obtained using the modeling approach based on deposition data. It was assumed that 25% of food was from the prefecture where the individual lived and 75% from elsewhere in Japan, with allowance made for foods being imported into Japan. In order to assess the uncertainties associated with these assumptions, estimates were made for Fukushima Prefecture assuming that 100% of the local food consumed was from the prefecture, both with and without allowing for imported food. The effect of this is seen in table C17.” [Appendix C126] –“It was not possible to include consideration of remediation in the dose assessment at this stage, because the effectiveness of the different measures to be applied in Japan was not known. Estimates of the effective doses from external irradiation that would be received by those who were evacuated if they were to return to their homes and regular lifestyles without any environmental remediation having been implemented are however shown in table C19. These estimates provide an upper bound to the doses that might be received in the future.” [Appendix C134] ++++++++++

CONCLUDING COMMENT: Evaluations of the accuracy and relevance of this report should be based on close reading and an understanding of issues such as those presented in this commentary at the very least. It is an extremely challenging document to navigate and parse, and perhaps this is cause for criticism in itself. There is room for valid criticism in several areas, and several underlying assumptions deserve scrutiny. Now is a good opportunity for informed commentary and feedback, because the forward steps taken in this report show that incremental change is possible. The only way to provide useful criticism is to examine the report in detail and address specific content. ++++++++++++

May 11, 2014 - Posted by | Uncategorized

2 Comments »

  1. “While leukemia and other 8. malignancies and illnesses show different correlations with radiation exposure, the maximum expected 60 mSv lifetime exposure would suggest an additional 0.6% risk of fatal cancer to those individuals. UNSCEAR, like many, myself included, feels comfortable in calling this a “low” extra risk.”

    Saying nothing about the entire range of diseases and malformed children, but comfortable with a single number of “fatal” cancers, this is enough to label it “low?” How many non-fatal cancers? How many other diseases? How many mutated limbs?

    Everyone responsible for Fukushima should be in prison for crimes against humanity, poisoning millions of people including generations yet to be born. There is no right to poison populations, whether groups can be convinced to label this poisoning “low” or not.

    Are these Chernobyl children exhibiting “discernible” problems, by UNSCEAR’s semantic word games?

    http://wp.me/PwAWe-dl

    They do love to hedge their bets. I’ve heard the “no biomarkers” defense before, but this time it’s presented more artfully. It seems to say the same thing: they don’t know how many people will be poisoned, mutated, sickened or what have you, but because there are presently no “biomarkers” to show this to their (bosses’) satisfaction, they can pretend that radiation was not to blame. The artful wording was to couch it in a hypothetical future discover of new biomarkers, that would negate their current assumptions.

    Nuclear power is criminal. The government of Japan’s crackdown on free speech and the obvious cover-up of the growing incidence of illnesses is also criminal. Their data can clearly not be trusted. How much independent examination did these people do to the sickened children of Northern Japan vs. how much did they rely on fudged Japanese official figures?

    “Low.” –So move your family there.

    Comment by Editor | May 12, 2014 | Reply

  2. […] findings of this presentation shows the manipulation of the nuclear industry when it comes to reporting health issues after nuclear accidents. As many nuclear reactor and […]

    Pingback by The truth concerning nuclear accident induced thyroid cancers. Japan TV report – Fukushima 311 Watchdogs | November 4, 2017 | Reply


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