Contaminants at issue

7.182. In the context of contaminants, Korea refers to examining the "toxicity" of contaminants.

Therefore, the Panel will begin by identifying the relevant contaminants and their potential adverse health effects.

7.183. The amount of radionuclides released, also called the "source term", comprises radionuclides released from the cores and confining structures into the environment during and after the accident at the FDNPP. These releases are documented in UNSCEAR data as well as in the Technical Volume 1 of the 2015 IAEA Director-General's Report. From this information, the Panel can conclude that the main radionuclides released during the accident were Cs-134, Cs-137 and I-131.⁷³³ Strontium and plutonium were also released.⁷³⁴ As noted in paragraph 7.65. above, the Panel has determined that Korea's measures at issue only definitively regulate Cs-134; Cs-137; I-131; Sr-90; and Pu-239 and 240.

7.184. Approximately 17.5 Pbq of Cs-134 and 15 Pbq of Cs-137 were released into the atmosphere. Caesium was the radionuclide released in the greatest absolute numbers as well as in the largest proportion to other radionuclides.⁷³⁵ In the initial accident 150-160 PBq of I-131 is estimated to have been released. We recall that I-131 has a half-life of 8 days. Therefore, after

731 Experts' response to Panel question No. 99(c).

732 In response to Panel question No. 118, Korea provided a list of over 70 exhibits that it says reflect Korea's scientific judgment. However, in its answer Korea did not explain how those documents were

considered by the Korean authorities or how they served as a basis for the imposition of the measure. Many of the exhibits contain the text of various measures Korea has adopted (including ones Japan does not challenge), but do not have any underlying reasoning or scientific evidence as to why those actions were taken. Other exhibits relate to bilateral communications between Japan and Korea that may seek or even transmit data on the situation in Japan, but they do not contain any evaluation or judgment by Korean government authorities.

733 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), pp. 148-149.

734 A full discussion of the accident as it occurred as well as the releases catalogued since then can be found in 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7).

735 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p. 149.

80 days, only 0.1% of the original I-131 activity would remain.⁷³⁶ I-131 was not released in significant amounts after the reactor was shut down.

Table 12: Estimates of radionuclides released from the FDNPP Codex

radionuclide Estimated core inventory in

Fukushima reactors 1 -3 (PBq)

NE=Not Estimated

Estimated release into the

atmosphere (PBq) NE=Not Estimated

Detected in environment after Fukushima? (Yes, No, Trace, Not Measured [NM])

Detected in fish / other food in Japan since Fukushima event?

(Yes, No, Not Measured [NM])

H-3 5.6 0.5 Y NM

C-14 0.0007 NE Trace NM

S-35 NE NE Trace NM

Co-60 0.009 NE Trace N

Sr-89 593 2.0 Y N

Sr-90 522 0.14 Y N

Tc-99 10,000 2.0 Y NM

Ru-103 9860 3.2 NM NM

Ru-106 2610 0.86 N N

I-129 0.0002 0.000002 Trace N

I-131 6,000 159 NM NM

Cs-134 719 17.5 Y Y

Cs-137 700 15.3 Y Y

Ce-144 5,920 0.011 Trace N

Ir-192 NE NE NM NM

U-235 0.014 NE N N

Pu-238 14.7 0.0000055 Trace N

Pu-239 2.6 0.0000068 Trace Y

Pu-240 3.3 0.0000068 Trace Y

Am-241 1.5 NE Trace N

Source: Analysis of caesium and additional radionuclides in food products from Japan and the rest of the world (Exhibit JPN-11), Table 7.⁷³⁷

7.185. Korea is correct that there are elements of uncertainty with respect to the direct release of caesium into the ocean. The IAEA provides a chart compiling all the various estimates as well as their variability, depending on the use of a normal or log-normal distribution. While there is considerable variability, the IAEA estimates that using the preferable log-normal distribution⁷³⁸ and a conservative approach of taking the uncertainty range from the smallest value to the largest one, one could accept a mean value of 3.9 PBq within a range of 2.7-5.7 PBq of direct deposition of Cs-137 to the ocean.⁷³⁹

7.186. The release of strontium was estimated to be three to four orders of magnitude less than the release of caesium.⁷⁴⁰ Strontium activity in the ocean was found to be much lower than Cs-137 activity. For Sr-90 the activity ratios were 0.02–0.24.⁷⁴¹

7.187. With respect to plutonium the IAEA confirms that:

736 Analysis of caesium and additional radionuclides in food products from Japan and the rest of the world, (Exhibit JPN-11), pp. 12-13.

737 Data in Columns 2 and 3 of Table 7 are from computer simulation data from Nishihara et al (2012), ENEA (2014), Povinec et al (2013), and Schwantes et al (2012). Environmental detection data (Column 4) from the Fukushima event from Kakiuchi et al 2012, Matsumoto et al 2013 [H-3]; Park et al 2013 [C-14], Priyadarsi et al 2011 [S-35]; Doi et al 2013 [Tc-99]; Zheng et al 2012, Yamamoto et al 2014 [Pu-239, 240;

JAEA 2014 [Pu-238]; Yamamoto et al 2014 [Am-241]; Suzuki et al 2013, Muramatsu et al 2014 [I-129];

Kojima et al 2012 [Co-60, Ce-144]. Fish / other food detection data (Column 6) are from FAJ 2015a (fish), MAFF 2015a and NRA 2015 (other foods).

738 This method is less sensitive to the assumptions about the relative accuracy of the original results.

739 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p. 157.

740 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p. 149.

741 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p. 154.

[O]nly a few samples collected after the Fukushima Daiichi accident showed the isotopic signature of reactor plutonium, in excess of the concentration ratios associated with historical nuclear weapon tests [97-99]. The concentration of plutonium isotopes found at the Fukushima Daiichi site (239Pu and 240Pu ~0.1 Bq/kg together [98, 99]) corresponded to the background level, indicating that the releases of plutonium from the Fukushima Daiichi units during the accident were limited.⁷⁴²

7.188. While acknowledging that there is possibility of locations with larger deposition, the IAEA concludes that "the data indicate that plutonium release due to the core melts in the Fukushima Daiichi NPP did not notably increase the environmental distribution of plutonium".⁷⁴³ Korea provides the Panel with data from 2016 and 2017, which indicate that the retained water in the PCVs in units 2 and 3 still contain significant amounts of plutonium.⁷⁴⁴ Japan argues that this confirms their conclusion that there was not a significant release of Pu-239 and 240 during the accident.⁷⁴⁵

7.189. With respect to plutonium in the ocean, Japan also refers to the fact that the ratios of plutonium radioisotopes in the North Pacific did not change after the FDNPP accident. Japan argues that scientific studies show that only 0.000015 PBq of plutonium were released as opposed to 10s of Pbq of caesium (1 million times less plutonium than caesium).⁷⁴⁶ Japan also notes that there were already 3.6 Pbq of plutonium in the North Pacific from nuclear weapons tests, both from global fallout and specifically additional US testing in the Marshall Islands.⁷⁴⁷ According to Japan this means that the existing plutonium in the North Pacific prior to the FDNPP accident was 240,000 times greater than what was released. Japan also notes that no plutonium bearing the

"fingerprint" from FDNPP has been detected in the ocean.⁷⁴⁸

7.190. The Panel also understands that plutonium from the FDNPP has been detected on land and that it is reasonable to conclude that some plutonium would also have been deposited in the ocean during the accident. Dr Thompson explained that the way plutonium binds to soil and sediment explains why it did not transfer from the land to the ocean.⁷⁴⁹

7.191. Korea argues that continuous leaks since the accident as well as the potential for future leaks must also be assessed. Because the situation at the FDNPP is dynamic and ever changing, Korea implies that the risk in food products cannot be assessed with sufficient certainty to conclude that Japan's alternative measure achieves Korea's ALOP.

7.192. The experts explained that examination of the source term to understand what radionuclides were released is important in determining what measures to apply for radiological protection purposes, such as developing a monitoring strategy⁷⁵⁰ or production and distribution restrictions. The experts concurred that after the initial release, the source term becomes less

742 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p. 149.

743 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p. 149.

744 International Research Institute for Nuclear Decommissioning and Japan Atomic Energy Agency, Analysis Results of the Retained Water Inside the Primary Containment Vessel (PCV) in Units 2 and 3 (24 November 2016), (Exhibit KOR-272), pp. 1-3.

745 2015 IAEA DG Report, Technical Volume 1, (Exhibit JPN-7), p.154.

746 Expert Meeting Transcript, para. 1.12; see also Steinhauser G. Fukushima's forgotten radionuclides:

a review of the understudied radioactive emissions. Environ Sci Technol. 2014;48:4649-63, (Exhibit JPN-11.1(99)), p. 9.

747 Expert Meeting Transcript, para. 1.12.

748 According to Japan, scientists can identify the source of a particular plutonium contamination on the basis of its "fingerprint" (most commonly by using the ratio of Pu-240/Pu-239 in the measurement). Plutonium originating from the Fukushima Dai-ichi reactors has a higher Pu-240/Pu-239 ratio than the plutonium that is widespread in the environment as a result of the nuclear weapons testing of the 1960s. Japan argues, and Professor Michel confirms that plutonium from the FDNPP has not been detected in the marine environment.

749 Expert Meeting Transcript, para. 1.13.

750 The Panel notes that the terms testing, monitoring, and sampling have been used interchangeably by the parties in several instances. However, these are different, yet inter-related concepts. As Professor Michel explains:

If you have a sample you test it for caesium-137. You can test a fish - the testing is a

measurement process, while monitoring means, I monitor the radioactivity in the area from the source, I have a plan, and using different tests I compile the different tests which is the whole picture given by the monitoring.

Expert Meeting Transcript, para. 3.34.

important as you have the ability to produce actual measurements in food.⁷⁵¹ All the experts agreed that knowing the remaining radionuclides contained in the reactor or the specific amount of leaks was not relevant to assessing the potential for specific products to be contaminated with radionuclides.⁷⁵²

7.193. Rigorous environmental and seawater monitoring is in place in addition to the food monitoring programme in Japan. Data from monitoring points in the harbour is available on an hourly basis and publicly available.⁷⁵³ In addition to Japan's measures both UNSCEAR and IAEA are reviewing the data and updating their publications regularly. If a new release were to happen that significantly changed the make-up of radionuclides in the environment then that might be a reason for modifying the testing or monitoring to take the adjusted mix of radionuclides into account. For instance, at the meeting with the experts Korea provided a recent study estimating the remaining radionuclides in the reactor.⁷⁵⁴ The study supports Japan's assertions with respect to the radionuclide make-up of the initial release. If a new leak or accident resulted in the release of these radionuclides that had not been released before or, if so, only in minor amounts, then that might be a reason to monitor for those radionuclides in food production and to test samples of imported products for their presence. The Panel asked the experts how long it might take between a major new release and the ability to detect evidence of it in food products. Recognizing the variables in such a situation (atmospheric vs oceanic, size of release, etc. . .) they all accepted that it would be relatively quick.⁷⁵⁵ Dr Skuterud noted that for an atmospheric release, new contamination might be detectable in vegetables the same day.⁷⁵⁶

7.194. Korea also mentions several other factors which it considers affect the assessment of the potential contamination of food products with radionuclides. In Exhibit KOR-213, three experts engaged by Korea seek to rebut the arguments and analysis presented by the two experts engaged by Japan.⁷⁵⁷ In particular, Korea raised the following issues: insufficient data on the types and amounts of radionuclides released from the FDNPP and the resulting contamination of the environment⁷⁵⁸; uncertainties about the melt progression of the core⁷⁵⁹; detection of caesium-rich microparticles, demonstrating new and previously unknown release pathways ⁷⁶⁰; seafloor sediments as a significant source of contamination, including "hot spots", where concentration levels of caesium are higher⁷⁶¹; detection within the 20km exclusion zone of highly contaminated fish that can migrate to other areas⁷⁶²; Japan uses testing equipment with insufficient detection capabilities⁷⁶³; and that the FDNPP is an active and ongoing source of contamination⁷⁶⁴. Japan, rejected Korea's arguments either as being unfounded or irrelevant.⁷⁶⁵ The Panel asked the experts to comment on the relevance of each of these issues and if it affected their views of whether Japan's analysis contained in Exhibits JPN-11 and JPN-148 was scientifically valid and reasonably supported. With respect to each issue, the consensus of the experts was that they were not relevant to an analysis of the potential for contamination in Japanese food products. The experts universally stated that actual measurements in food were what are required.⁷⁶⁶ The

751 Experts' responses to Panel question No. 91 to the experts.

752 Experts' responses to Panel question No. 59 to the experts.

753 Indeed it was spikes in readings at these monitoring points that alerted authorities to the leaks that had not initially been disclosed in May and June of 2013.

754 Japan Atomic Energy Agency / International Research Institute for Nuclear Decommissioning, Analysis Results of Waste Samples (23 February 2017), (Exhibit KOR-302).

755 Experts' responses to Panel question No. 16 to the experts.

756 Dr Skuterud's response to Panel question No. 16 to the experts.

757 Professor Timothy Mousseau, Dr. JinHo Song and Professor Yongsung Joo Joint Statement (23 August 2016), ("Statement of Korea's experts"), (Exhibit KOR-213).

758 Korea's second written submission, paras. 52-53.

759 Statement of Korea's experts (Exhibit KOR-213), p. 15.

760 Statement of Korea's experts (Exhibit KOR-213), p. 16.

761 Korea's first written submission, paras. 142-150; second written submission, paras. 54-59.

762 Comments on experts' responses to Panel question No. 73.

763 Korea's second written submission, paras. 86-89.

764 Korea's second written submission, paras. 68-80.

765 Japan's second written submission, paras. 253-279, 295-297; responses to Panel question Nos. 51, 61, 108; comments on Korea's responses to Panel question Nos. 147, 149, 150; comments on Korea's comments on the expert responses, paras. 45-51, 136-157; comments on the expert responses to Panel question Nos. 4, 5, 17, and 29 to the experts.

766 Professor Anspaugh expressed the consensus view of the experts when he stated that you should not take data like this and try to model what will be in fish. "The basic line is if you're concerned about what's in the fish, you need to go and ask the fish." Expert Meeting Transcript, para. 3.33.

experts also noted that none of these issues affected their views on whether the analysis in Exhibits JPN-11 and JPN-148 is scientifically valid and reasonably supported.⁷⁶⁷

7.195. In particular, with respect to each of the issues raised by Korea the experts clarified that:

While some uncertainties remain regarding the amounts of radionuclides released from a.

the FDNPP, the experts confirm an overall consensus about the scope of the initial releases. The experts consider such uncertainties of little relevance from the perspective of protection against radiation exposure from food in view of the available food contamination data.⁷⁶⁸

The experts state that the status of the damaged core, in particular its melt progression, b.

is of little relevance from the perspective of protection against radiation exposure arising from contaminated food products.⁷⁶⁹

Professor Anspaugh notes that caesium-rich microparticles were also discovered after c.

the Chernobyl accident.⁷⁷⁰ According to all of the experts, detection of these particles is of little relevance for purposes of protection against radiation exposure from contaminated food products.⁷⁷¹

Likewise, the experts agree that contamination of sediments and existence of "hot spots"

d.

is of little relevance from the perspective of protecting against radiation exposure from contaminated food products.⁷⁷²

As regards the instances of highly contaminated fish caught within the 20 km exclusion e.

zone around the FDNPP, the experts note that such fish would not be relevant to the assessment of contamination of Japanese food products, as commercial fishing in that area is prohibited.⁷⁷³.As regards the possibility of highly contaminated migratory fish that may have spent time within the 20 km exclusion zone being caught outside it and eaten by consumers, the experts note that such migratory fish are unlikely to be highly contaminated as they will not have lingered within the 20 km exclusion zone.⁷⁷⁴

With regard to the alleged use of imprecise caesium detection equipment by Japanese f.

inspection authorities, the experts note that while more accurate measurements can be determined by the germanium semiconductor detector recommended by Korea, the sodium iodide detector is satisfactory because the level of detection is still well below the intervention level of 100 Bq/kg.⁷⁷⁵

Regarding the argument alleging that FDNPP remains an active and ongoing source of g.

contamination, the experts note that a possibility of future leaks is of little relevance for determination of food contamination, unless a significant release goes undetected, which is unlikely in view of Japan's water monitoring programme.⁷⁷⁶

7.196. With respect to the characterization of the hazard arising from the potential presence of these contaminants in food products, the Panel recalls its explanation in section 2.2 above, that

767 Experts' responses to Panel question Nos. 4, 12, 13, 17, 25, 31, 37, 39, 46, 53, 73, 104, 105, 106, and 109 to the experts.

768 Experts' responses to Panel question No. 12 to the experts.

769 Experts' responses to Panel question No. 13 to the experts.

770 Professor Anspaugh's response to Panel question No. 17 to the experts.

771 Experts' responses to Panel question No. 17 to the experts. In particular, Professor Michel states that due to insolubility of caesium-rich microparticles "they would survive the passage through the human gut and contribute less to the intake compared to the usual soluble Caesium." Professor Michel's response to Panel question No. 4 to the experts.

772 Experts' responses to Panel questions No. 39, 46, 104, 105, and 106 to the experts.

773 Expert Meeting Transcript, paras. 4.16, 4.89, and 4.97.

774 Expert Meeting Transcript, para. 4.6, where Dr Thompson indicated that such a risk was "negligible".

Dr Skuterud explained with reference to the example of mackerel, which is a migratory fish species, that "[t]he 20 km zone is a small area for migratory mackerel so the likelihood of them staying there long enough to obtain significant concentrations is, for biological reasons, very low." Expert Meeting Transcript, para. 3.150.

775 Experts' responses to Panel question No. 61 to the experts.

776 Experts' responses to Panel questions No. 15, 55, and 59 to the experts.

each of the radionuclides has the potential to cause stochastic effects in humans – namely cancers. The effects of specific radionuclides depend on the properties of the isotope, absorption and excretion rates, and biological half-lives. Caesium reacts in the body in the same way as potassium being absorbed in tissue and the blood stream, whereas strontium mimics calcium attaching to and remaining in the bones. Plutonium is absorbed in body fluids, deposited in the liver and bones, and then travels to other organs through body fluids. Caesium has a biological half-life of 110 days, meaning one-eighth of the amount of caesium will remain in the body within one year of ingestion. Strontium has a biological half-life of 35 years. While plutonium's is 200 years.⁷⁷⁷ These properties affect not only the contamination concentrations in food products, but also the rate at which the contamination moves up the food chain to higher order animals and eventually to humans, the so-called transfer factor. For example, as strontium collect in bones strontium in a fish would not necessarily transfer to a human consuming it if they were not eating the bones.⁷⁷⁸ Similarly, the uptake of caesium will depend on the environment (freshwater, seawater, forest) it is deposited in.⁷⁷⁹

7.197. Through an understanding of the properties of these radionuclides and their transfer factors dose coefficients have been developed to determine guideline levels for human consumption. The dose coefficient was developed by the ICRP. The ICRP was guided by the principle that human exposure through ingestion of man-made radionuclides should not add significantly to doses from background exposure and other sources – such as medical treatments and air travel.⁷⁸⁰ It is our understanding that the development of the dose coefficient takes into account the ALARA principle as well as the LNT approach.

7.198. The first version of the Codex guideline levels for radionuclides in food were developed by Codex in 1989 as a result of the Chernobyl accident in 1986. The Codex Committee on Contaminants in Food (CCCF) agreed to review the guideline levels after the FDNPP accident as is prudent when a significant new exposure takes place. Such review has not resulted in any modifications to the standards. The Codex Secretariat explained to the Panel that the CCCF

"considered the revisions of the GLs for radionuclides in the CSCTFF between 2012 and 2015 and agreed to 'discontinue of work on the revision of the GLs for radionuclides in the GSCTFF including the development of guidance to facilitate the applications and implementation of the GLS' (REP13/CF, paragraphs 44-54)". The CCCF further agreed "that any possible new work should be delayed until such time as the outcome of the review of the ICRP became available, which might lead to a revision of the Codex GLs in the GSCTFF' (REP15/CF, paragraphs 128-134)".⁷⁸¹ Dr Skuterud explains that the review of the guidelines by CCCF was not triggered by new scientific information or views about risks. It was rather a result of a stronger need to obtain a better description of how the values in the guidelines were derived and how they apply relative to other international standards.⁷⁸² The experts all agreed that the review of the guideline levels did not impact the sufficiency of the evidence on overall dose limit, individual dose limits, or how to test for radionuclide contamination in food products.⁷⁸³ The Codex also uses the ALARA principle when adopting its guidelines for substances in foods.⁷⁸⁴ Both parties use all the Codex guideline levels

777 See Table 1 above.

778 Korea argues that the boiling of shells and bones in the making of soups and stews could release strontium in a way that would make it bioavailable to human consumers. The experts stated that studies could be done to test this hypothesis, but Korea did not present any. Based on general knowledge, the experts explained that this means of transfer of strontium was unlikely because of the known properties of calcium when cooking. See experts' responses to Panel question No. 41 to the experts.

779 Expert's responses to Panel question No. 2 to the experts. See also Dr Skuterud's response to Panel question No. 60 to the experts.

780 See ICRP Publication 103: 2007 Recommendations, (Exhibit KOR-1), (Exhibit ICRP-3). Dr Thompson's response to Panel question No. 6 to the experts.

781 Codex Secretariat's response to Panel questions.

782 Dr Skuterud's response to Panel question No. 9 to the experts.

783 Experts' responses to Panel question No. 9 to the experts.

784 At the meeting with the experts Korea had as part of its delegation Dr A Randell who had served as the Secretary of the Codex until 2003. Dr Randell explained how Codex uses ALARA in setting guideline levels.

However, Dr Randell referred to the processes for deriving limits for other contaminants (arsenic, acrylamide in food and other alfatoxins) and not specifically the radionuclide guideline levels. Expert Meeting Transcript, para. 2.25.

문서에서 KOREA – IMPORT BANS, AND TESTING AND CERTIFICATION REQUIREMENTS FOR RADIONUCLIDES (페이지 122-128)