PART 2.4: FOOD
Keeping contaminated food off the market is essential for minimizing internal exposures to radiation. This risk is chronic because cesium and other radionuclides remain in the environment for years — decades in many cases — usually migrating deeper into the soil, and even if the problem appear to be controlled at some point, it is still present. The Japanese government quickly instituted a food monitoring program in March 2011, and in scale and comprehensiveness it has been unprecedented. Not everything is checked, however, which is why the appearance of dozens of independent, citizens-run food testing labs all over the country is extremely welcome. Also welcome are independent tests of actual meals being eaten by residents of Fukushima and elsewhere. While the relative paucity of tests for strontium remains a matter of concern, the independent tests tend to support official findings, that less that 1% of the food being produced in Fukushima has above-limit concentrations of cesium, and virtually none of this is finding its way onto the market. Farmers themselves deserve almost all the credit for this. The biggest food risks — wild mushrooms and vegetables, and wild boar and other game — are well known, and will continue to pose problems for years to come.
One of the biggest concerns in the wake of the Fukushima NPP disaster has been the effect of radioactive contamination on the food supply. As explained in the section on internal contamination screening, if not dealt with effectively, radioactive contamination in the food chain chain can easily lead to chronic internal contamination in a large proportion of the population, as it has in the Chernobyl area. The goal, of course, is to minimize or even eliminate this risk in the entire population if possible. The past four years since the Fukushima accident have greatly increased our knowledge of what steps and methods, in farm fields, in fisheries, in testing labs, and in terms information provided to the food supply chain as well as to consumers, can best help reduce radiation exposures to the public from food. At this point, when taken together, the food testing data, both official and independent, and the internal contamination screening data, both official and independent, indicate that the measures have been very effective overall, much better than in the Chernobyl region, for comparison. But these exposures are not yet eliminated entirely, nor are they likely to be for some time. Also, it is important to acknowledge that we do not have a clear picture of people’s internal exposures overall during the first months of the disaster.
For agricultural products, while financial and technical government assistance has been essential, most of the credit for the success seen so far is due to the farmers themselves, who have studied, tested, destroyed entire crops, tried new soil treatments, replanted, tested, and so on for several years, until they could grow food they themselves were willing to eat and sell. The process is not perfect. Though the Japanese government standard for cesium contamination in food, at 100 Bq/kg, is the lowest in the world, it’s important to note that many farmers in Fukushima, as well as in Tochigi and other affected places, have taken it upon themselves to only sell food that is well below that. We understand the position taken by many people and groups that no cesium or other radioactive contamination in food is acceptable. People absolutely have a right to uncontaminated food. Nevertheless we believe that everyone involved has been making sincere efforts to reduce the contamination in Japanese food to the lowest possible levels.
We give a basic summary of findings regarding food and Fukushima immediately below, followed by more in-depth information.
2.4.1 — Basic findings
2.4.1a -Rice:
Since 2012, every bag of rice produced in Fukushima Pref. has been tested for radioactive cesium. Since 2012, the rate found over limit (100 Bq/kg) has been less that 0.01%. In the past year, as of March 18, 2015, none of the 10.9 million bags of rice tested was over the 100 Bq/kg limit. This is a remarkable achievement and deserves to be applauded, especially because it is due primarily to the efforts of farmers.
— 2012: 10,246,086 bags measured, 71 over 100Bq/kg ( 0.0084 %) — 2013: 11,006,534 bags measured, 28 over 100Bq/kg ( 0.0003%) — 2014: 10,966,597 bags measured, 0 over 100Bq/kg ( 0%)
(as of March 18, 2015)
In 2014, however, it should be noted that 1909 bags (0.02%) had between 25–50 Bq/kg; 11 (0.0001%) had between 51–75 Bq/kg; and 1 bag (0.00001%) had between 76–100 Bq/kg.
Source: Fukushima Prefecture food test information, rice
2.4.1b-Food products in general:
Government test results indicate that the amount of cesium-contaminated food being produced in Fukushima and nationwide has steadily decreased since 2011, and is currently about 1% of the total in Fukushima, and 0.1% nationwide. People are generally surprised to learn that in Fukushima in 2012 it was only about 4%. These overall figures don’t tell the whole story, however, and details follow below.
Nationwide results: — FY2011: 137,037 items tested: 1,204 over 500 Bq/Kg (0.88%) — FY2012: 278,275 items tested: 2,372 over 100 Bq/Kg (0.85%) — FY2013: 326,582 items tested: 975 over 100 Bq/Kg (0.29%) — FY2014: 280,296 items tested: 480 over 100 Bq/Kg (0.17%)
Fukushima results: — FY2011: 21,549 items tested: 718 over 500 Bq/Kg (3.3%) — FY2012: 34,857 items tested: 1377 over 100 Bq/Kg (3.9%) — FY2013: 40,759 items tested: 608 over 100 Bq/Kg (1.5%) — FY2014: 35,461 items tested: 242 over 100 Bq/Kg (0.9%)
Source: Ministry of Health, Labor, and Welfare (MHLW) food test results, with breakdowns by prefecture and food type
2.4.1b -Seafood:
A lot of testing focuses on fish, or more specifically, on “fisheries products,” which includes shellfish, octopus and squid, as well as seaweed and a few other items. The number of items being tested was steadily increased through 2014. Coastal and trawl fishing off Fukushima Prefecture are still banned, except for experimental fishing for the purpose of providing items to test.
Percent over 100 Bq/kg: — April-June 2011: 57.7% — April-June 2012: 21.6% — April-June 2013: 4.6% — April-June 2014: 1.0% — Jan-Feb 2015: 0.2%
Nationwide: 1% or less have been over the 100 Bq/kglimit since mid-2012, and none since Oct. 2014.
Source: Fisheries Agency of the Ministry for Agriculture, Forestry, and Fisheries testing results
2.4.1d -Greatest risks:
Certain wild plants and animals gathered or hunted as food are known to present the highest risk of contamination from cesium. Plants that people in contaminated areas have been advised to avoid include wild mushrooms, as well as bamboo shoots, wild berries, and several other varieties of edible plants. Wild boar is quite likely to be very contaminated, as is deer, bear, and many species of wild fowl. Freshwater fish living in lakes or ponds may show high cesium levels too. To date, individuals in Fukushima who have had the highest levels of internal contamination have been elderly people who have continued to eat these foods despite being advised against it. Also, it is not widely appreciated that many mushrooms and wild boar from prefectures other than Fukushima have tested over-limit for cesium.
2.4.1e-Consumer sentiment:
Despite what many of us consider the very low levels of contamination in food from Fukushima which is being sold, many people do not seem to be aware of it. The Consumer Affairs Agency of Japan has carried out surveys twice a year since 2013 to find out how many people are reluctant to buy food from Fukushima. About 17% of respondents from the survey done in 11 prefectures in Feb. 2015 said they are cautious about buying food produced in Fukushima, a rate slightly lower than last August (20%) but slightly higher than a year ago (15%). Only 21% knew that Japan’s safety standards for radiation in food are stricter than in the United States or Europe, but 22.5% nevertheless felt they should be made stricter. In addition, a recent study shows that there is a difference in attitudes towards eating Fukushima food within the prefecture itself. While about 75% of families in Minamisoma say they avoid Fukushima food, for instance, only about 20% of the families in Miharu, near Koriyama, do. Nevertheless residents of both towns have similarly low levels of detection of internal cesium; several years worth of internal contamination testing shows that avoiding food from Fukushima has not made the Minamisoma families detectably “safer.” Based on the very large amount of good data that is available, it’s difficult to say that avoiding Fukushima food has a clear rational basis at the moment, but it fulfills a different kind of need, namely providing a concrete step that a mother can take on behalf of her family to reassure them, as well as herself, that she is doing everything she can to keep them out of risk. Most of us agree that these people should not be told that they are wrong to do so.
Consumer Affairs Agency survey results (in Japanese)
WSJ: Nearly One in Five Japanese Reluctant to Buy Fukushima Food, March 11, 2015
arXiv: Whole body counter surveys of Miharu-town school children for four consecutive years after the Fukushima NPP accident (Hayano et al, 2015)
2.4.2 — Food: In-Depth
2.4.2a — Overview Of Japanese Government Food Monitoring
Food monitoring was implemented by the central government by March 17, 2011, under the jurisdiction of the Ministry of Health, Labor, and Welfare (MHLW), which has responsibility for food safety, and gradually expanded. The Ministry of Agriculture, Forestry and Fisheries (MAFF) also conducts separate inspections, particularly of seafood products. While farm products from seventeen prefectures, including Miyagi, Ibaraki, Tochigi, Gunma, Chiba, and Tokyo, are regularly inspected, outside interest is focussed on Fukushima. Nevertheless, during FY2011, only 15% of the samples tested by the government were from Fukushima; 12% were from Fukushima during FY2012, FY2013, and FY2014. The monitoring system is designed to interdict contaminated food before it reaches the market. Particularly in its early stages in 2011, the methods and selection criteria for what would be checked, when, and how were fairly opaque and difficult to ascertain, but even now after four years, the rationale sometimes remains somewhat obscure even to people who try to keep a close eye on the situation.
MHLW food safety info:
English main site
Index of test results and related information on policies, etc
MHLW main food test portal (Japanese):
Access to monthly press releases (Japanese):
MAFF online test results in English
JAEA launched a new website early 2015 that includes data from other gov’t agencies for different categories of food, as well as drinking water:
JAEA: Database for Radioactive Substance Monitoring Data
Produce, including rice, as well as meat and seafood, is generally tested on a town-by-town (municipality) basis. When an item, such as spinach, is tested in a particular town and found to exceed the government’s 100Bq/kg limit for cesium 134 and 137 combined, for instance, all spinach from that town is embargoed and can’t be sold. Produce from farms other than the one the sample came from are rechecked as well. Embargoed towns are allowed to sell the item again when it has passed several inspections (usually three, but the number varies according to the crop and season) within the span of a month. In addition, when an item is found to contain 50Bq/kg, that is, half the allowable limit, the frequency of inspections of that item is increased in that town. Some areas are released from embargo after a few months, while others have remained under embargo for certain food items, particularly wild mushrooms, mountain vegetables (“sansai”), and wild game, since 2011 or 2012. The actual regulations have changed a few times since 2011, and the most recent detailed information, as well as tables showing what items are inspected in which prefectures, can be found in a long MHLW press release from March 20, 2014, available here:
In addition, tables showing which items have been embargoed, where, and for what period, can be found in this document from March 10, 2015:
“Request for shipment restraint and other measures” as of February 3, 2014
Our most informed colleagues agree that a lot of the public frustration about the obscurity and opacity of official information about food testing results stems from the fact that the food monitoring program was not designed primarily to inform the public about the contamination levels, but to prevent food which is over the limit from reaching the market. Consequently the program focuses mainly on the production side, and informing producers and distributors, as well as government officials, of the testing criteria for different localities, and of decisions such as distribution bans for specific municipalities or prefectures. Despite useful initiatives like a searchable database for Fukushima Prefecture food linked below, informing the public has been clearly secondary. We encounter the consequences of this frequently: there is no simple searchable government database of food test results for the whole country; the list of banned items is basically a table on a PDF which does not include a single map; most people still do not understand what the contamination limits actually mean; and most people are not aware that there are hundreds of items in Fukushima that have consistently been under the detection limits for contamination for two years, and quite a few items outside of Fukushima which frequently test over-limit.
It’s not only regular citizens whose understanding is hampered by the poor communication until now. Some official overseas agencies apparently have not fully understood the Japanese food testing policies or results. In 2012, the WHO, for instance, estimated internal contamination levels of the Japanese population used in its Fukushima reports based on the percentage over-limit that food monitoring detected, without acknowledging that over-limit items were being banned and effectively kept off the market. The official agencies in Japan that are responsible for the monitoring should demonstrate that they care about making it easier to find and interpret the tests they have been doing. The information is being collected and made available, and communication has definitely improved, but it needs to be vastly friendlier.
Conscientious and thorough food monitoring will need to be continued for years, and in fact there are many good reasons to expand the testing in prefectures outside of Fukushima. But there is a real risk is that public interest will decrease to the point that the government can find excuses to scale it back instead. And while the Japanese 100Bq/kg limit for cesium in food is the strictest in the world, some insist that it is still too high. This in itself is worthy of a lengthy debate, and while the subject is controversial, just about everyone agrees that less is better.
2.4.2b — Food In General
Nationwide results: — FY2011: 137,037 items tested: 1,204 over 500 Bq/Kg (0.88%) — FY2012: 278,275 items tested: 2,372 over 100 Bq/Kg (0.85%) — FY2013: 326,582 items tested: 975 over 100 Bq/Kg (0.29%) — FY2014: 280,296 items tested: 480 over 100 Bq/Kg (0.17%)
Fukushima results: — FY2011: 21,549 items tested: 718 over 500 Bq/Kg (3.3%) — FY2012: 34,857 items tested: 1377 over 100 Bq/Kg (3.9%) — FY2013: 40,759 items tested: 608 over 100 Bq/Kg (1.5%) — FY2014: 35,461 items tested: 242 over 100 Bq/Kg (0.9%)
Source: Ministry of Health, Labor, and Welfare (MHLW) food test results, with breakdowns by prefecture and food type:
We regularly hear reports of contaminated items being found, and many people may assume that these reports represent a significant proportion of everything that’s being tested, and that a lot of contaminated food is in circulation. But examining the MHLW database, which is open for download, and summaries released in English, shows that this is not the case. This data provides results for food items tested before being approved for sale. These include agricultural products, livestock products, fishery products, milk, wild game, drinking water, and others. Using this data it is possible to get an idea of how much food has been over-limit, and to judge the effectiveness of the steps taken to reduce it. Please note that until April 2012 the Japanese limit for cesium in most food items was 500 Bq/kg, in line with standards in most other countries, but a lower limit of 100 Bq/kg went into effect after April 2012. This data is reinforced by surveys and actual tests of what people are eating, and by internal contamination screening results, as well as independent food test results (described below).
When looking at overall results, it’s important to be aware of the proportions represented by various categories of food being tested, because the picture changes somewhat depending on what’s being looked at. Most people are primarily interested in knowing about agricultural products like fruits and vegetables from Fukushima, however, and fish in general. But a large proportion of the tests so far have been for livestock products, which have had a very low detection rate (less than 1%). During FY2011, the first year of testing, more than 90,000 of the samples were for beef; this appears to be an outsized response to the contaminated rice straw used as feed in some locations that year. During FY2012, more than 50% of the samples still seem to have been for beef, with over 125,000 beef samples measured through Dec., 2012. A large proportion is still for beef, but we think reductions in the number of these samples accounts for about half of the decrease in overall numbers tested between 2013 and 2014.
One persistent concern is that even though only about 1% of food produced in Fukushima is presently over-limit, and is being effectively kept off the market, it may be possible for some people to eat a lot of highly contaminated food nevertheless. People growing or gathering food for their own consumption are not required to have it tested, but are encouraged to do so. Not surprisingly, the highest levels of internal cesium contamination among Fukushima residents found so far has been in people who ignored this advice and regularly ate untested wild or homegrown food, particularly wild mushrooms and berries, or game like wild boar and deer, which are known to present a particularly high risk of contamination. Some of these items are circulated among friends and relatives, but are not approved for sale. We should expect exposures from untested food to continue to happen for many years to come, since the highly contaminated wild foods are found in forests which, as described in the “Environment” section above, are not likely to undergo any kind of effective decontamination, and human nature shows that some temptations are irresistible even when negative consequences are known. At present, these cases form the “long tail” of the distribution, a persistent but fortunately quite small percentage of the overall pattern of consumption of radioactive food.
Similarly, while food intervention measures were instituted fairly quickly in March 2011, they were not immediately effective, and many people undoubtedly ate some contaminated food during the early period, which contributed to their initial doses. The fact that it was still winter in Fukushima, and the ground was frozen and often snow-covered, means that there were almost no vegetables in the ground, which was very fortunate. This is not necessarily the case in prefectures further south which also received fallout.
Fukushima Pref has a page in English where items can be searched by type and date:
Fukushima Prefecture food monitoring info
This is a useful interactive map of how food contamination levels have changed in Fukushima, produced by Tokyo Polytechnic University:
Radiation and Food Map in Japan
Prof. Haruhiko Okumura of Mie University has been maintaining a searchable archive of the MHLW database (in Japanese) :
Mie Unv. searchable food radiation database
MHLW/National Institute of Public Health searchable food radiation database
Recent articles and papers about changing levels of radioactivity detected in food in Fukushima:
Nature: Fukushima data show rise and fall in food radioactivity, February 27, 2015
Environmental Science & Technology: Analysis of Japanese Radionuclide Monitoring Data of Food Before and After the Fukushima Nuclear Accident (Merz, Shozugawa, Steinhauser; 2015)
2.4.2c — Rice
As mentioned above, remediation of rice fields in Fukushima has been an extremely high priority, and the central government, prefectural and local governments, local farmers’ cooperatives, and individual farmers have all devoted tremendous time and resources into learning how to grow uncontaminated rice and putting it into practice on a large scale. The results have exceeded expectations.Detailed information on the “Zenbukuro kensa” ( all-bag testing) rice testing results can be found here:
Fukushima Prefecture food test information, rice
This excellent recent paper describes the testing process for rice in detail:
Nature: Inspections of radiocesium concentration levels in rice from Fukushima Prefecture after the Fukushima Dai-ichi Nuclear Power Plant accident (Nihei et al, 2015)
Rice grown in Fukushima is labeled with a barcode, which consumers can use with a smartphone to call up data about the bag, including where it was grown, when harvested, and its measured cesium content (if any). Similar barcodes are gradually being introduced for other agricultural products.
Fukushima Pref: Testing of All Rice Grown in Fukushima Prefecture (JA Aizu Iide) Oct 2013
As described in the paper by Nihei et al above, in 2011 preliminary surveys and inspections were done of rice fields in all municipalities in Fukushima, which determined that 0.8% of all areas in Fukushima Prefecture had rice contamination levels higher than 100 Bq/kg. Based on this, no-planting areas were determined.
— Rice from most areas of Fukushima is allowed to be sold if it passes the “zen-bukuro” (whole bag) screening, with detected levels of Cs below 100 Bq/kg.
— Several areas, generally within the boundaries of the former and current evacuation zones, allow experimental planting only: rice is grown in a few selected locations, tested, and disposed of. This includes the parts of Minamisoma that lie within 20km of Daiichi, and the still-restricted western slice. Also the entire towns of Namie, Futaba, Okuma, Tomioka, and Katsurao.
— Other areas, including the rest of Minamisoma, as well as Iitate, Naraha, and parts of Kawauchi and Kawamata, are currently designated as “prepare to resume planting” areas. Rice can be grown, farmers can get experience with remediation and soil additives (potassium, zeolite, etc), and the rice is tested under the “zen-bukuro” screening system. Rice that is under the 100Bq/kg limit can be sold at local events, but not on the open market. Rice from the “experimental planting only” areas can’t be sold at all.
Through this testing process, more rice fields have returned to full production each year.
MAFF map of changes in rice planting areas for 2015 (in Japanese):
— — “Tobichitta jikken”
An unusual problem from 2013–2014 highlights the continuing vulnerability of agricultural fields to wind-blown and other contamination. For the 2013 Fukushima rice crop, as mentioned above, only 28 of almost 11 million bags were found to be above 100 Bq/kg. 27 of these came from fields in Old Ota-Village in Minamisoma, and ranged from 110 to 180 Bq/kg. Rice from this town also had a much higher proportion of rice above 50Bq/kg (it has generally been less than 0.1%). Farmers and officials were extremely puzzled that this one group of fields was higher than others which had been treated in the same way, and MAFF conducted a series of tests of soil, water, etc.. They released a report in Jan. 2014, and an update in March 2014. They saw some differences in soil which could have increased Cs uptake, but not enough to account for what the screening showed. They pretty much ruled out any sudden increase in water contamination, etc., and suspected an “external factor.”
Govt reports (in Japanese):
Fukushima Pref/ MAFF.: Factors leading to a high concentration of radioactive cesium in rice and their countermeasures, Jan. 2013
Meanwhile on Feb 14, 2014, an information session was held in Minamisoma, at which officials suggested that based on maps, wind direction, and timing, airborne contamination from Daiichi in August 2013 was the cause. At that time work was being at Unit 3 at Daiichi, in which a large girder was lifted from the roof, releasing highly contaminated dust which was blown by fairly strong winds. Because of the timing, the work being done at Unit 3 at the time, the wind speed and direction, the areas affected, and measured increases in air radioactivity in the affected areas at the time, dust from Unit 3 is the best explanation so far.
On the one hand it seems implausible that this relatively small amount of dust could be carried so far, but again, this remains the best explanation. It’s possible that in each of these fields, a relatively small percentage of rice plants were directly affected, the dose rate of the dust being high enough that when the rice was processed, rice from entire fields ended up with 110–180 Bq/kg.
All of which should be a cautionary lesson not to assume that farm field contamination problems, once solved, will stay solved.
2.4.2d — Fish
A lot of testing focuses on fish, or more specifically, on “fisheries products,” which includes shellfish, octopus and squid, as well as seaweed and a few other items. These items are included in the MHLW testing, but the MAFF conducts its own tests and maintains a separate database as well, through its Japan Fisheries Agency (JFA) branch.
This Fisheries Agency report from May 2014 provides a detailed explanation of the policies, methods, and results of seafood monitoring:
Report on the Monitoring of Radionuclides in Fishery Products(March 2011 — March 2014)
Downloadable MAFF fisheries test reports (Japanese only):
Page with links to fisheries test reports in English
Results of tests for strontium, June 2011- Nov 2014
(relatively little testing for strontium has been done):
Fairly informative Q&A about seafood monitoring (English):
In addition, monitoring results from tests conducted by prefectural governments, as well as by a number of fisheries associations, are published online. List and links at the bottom of this web page:
Fisheries monitoring results from tests conducted by prefectural governments, etc.
A typical individual MAFF report, in this case covering from April, 2014- Feb 2015
The same report in .xls format.
It’s a very detailed report, with over a thousand individual test entries, giving results, testing parameters, dates, the location the fish were caught, etc.. The data can be downloaded in both pdf and excel formats, and all the older data is available. These reports are nevertheless unwieldy, and it is difficult to extract trends regarding specific locations, or kinds of fish. As mentioned above, in October 2012, a US-based researcher Ken Buesseler at the Woods Hole Oceanographic Institute released a study that used the same MAFF database, and analyzed it to show what kinds of fish were decreasing in contamination and where, and what kinds were not:
WHOI press release: Fishing for Answers off Fukushima, October 25, 2012
Science Magazine: Fishing for Answers off Fukushima (Buesseler, 2012)
A more recent paper provides another excellent overview of changes in radionuclide levels in the ocean as well as in fish since 2011:
Nature: Fukushima radionuclides in the NW Pacific, and assessment of doses for Japanese and world population from ingestion of seafood (Povinec, Hirose, 2015)
The Ministry of Agriculture, Forestry, and Fisheries should be preparing and providing these kinds of analyses and visualizations itself, to help citizens evaluate the risks.
2.4.2e — Independent Testing Overview
Those who criticize the overall food monitoring system call it “spot checking,” and insist that it is too porous, and must be allowing a lot of contaminated food onto the market. But in fact results frequently released by the many independent, citizen-run food testing labs that have sprung up, such as CRMS (Citizens’ Radioactivity Measuring Station), as well as by COOP Fukushima, which tests food it sells itself and conducts regular “duplicate portion” surveys of members’ households, and the Mina no Data project, which provides a searchable online database of food test results from over 20 citizens-run testing labs, almost always reinforce the government’s claims (see links and summaries below). A higher percentage of contaminated items is often found by independent labs, but the labs themselves acknowledge that people usually bring food they’re particularly worried about to be tested, like wild or homegrown items or other “grey market” products which have actually not been approved for sale and which are not representative of what it actually found in stores. Above-limit items can be found, but even independent watchdog groups rarely report finding them on supermarket shelves, and their reports tend to focus instead on instances of any contamination at all that has been detected. The independent labs play an important role in helping keep pressure on the government to be accurate and thorough in its monitoring, and for testing things the government doesn’t.
— — COOP Fukushima:
In order to see how official food testing compares to independent tests, it’s worth looking at COOP Fukushima’s independent “duplicate portion” studies from late 2011 to early 2015. These studies sample only a few hundred families in Fukushima, but they’re very carefully done. The duplicate portion studies tend to show a bit higher intake than the government’s “market basket” studies do, most likely because some families who participate in the COOP study regularly consume many home-grown products that have not been tested.
Test description (in Japanese)
Results for July 2014 — Feb 2015 (in Japanese):
Fukushima Minpo: Home-cooked meals in Fukushima found to include no detectable radioactive cesium, March 7, 2015
Meals of 600 families have been tested since Nov. 2011. Each participating family prepared six meals over a two-day period for testing. Almost all of the households in the survey eat locally-produced food and drink tap water.
Results summary:
— Test A. 100 households were tested between Nov. 2011-April 2012; Cs detected in meals of 10 families (10%). — Test B. 100 households were tested between June-Sept, 2012; Cs detected in in meals of 1 family (1%). — Test C. 100 households were tested between Dec 2012 and Feb 2013; Cs detected in meals of 7 families (7%) — Test D. 100 households were tested between July 2013 and Oct 2013; Cs detected in meals of 2 families (2%) — Test E. 100 households were tested between Nov 2013 and Feb 2014; Cs detected in meals of 4 families (4%) — Test F. 100 households were tested between July 2014 and Feb 2015; Cs detected in meals of none (0%)
In each set of tests, 90% or more of the households ate food from Fukushima Pref., though the percentage varies, as does the proportion that each purchased at a supermarket vs home-grown.
In most cases, when cesium was detected in the COOP survey samples, it was barely at the detection level. The highest measured levels of Cs 134 and 137 combined in the food consumed by the participating households are:
— Test A: 11.7Bq/kg /day (one family, which ate a lot of home-grown, unchecked food) — Test B: 3.2Bq/kg /day — Test C: 3.5Bq/kg/day — Test D: 1.6 Bq/day — Test E: 2.6 Bq/day
NOTE: It’s worth comparing these results with cesium intake levels during the atomic bomb testing period. For instance, according to Japanese government data, in 1963, every household in the country was consuming 4.4Bq per person per day nationwide. Similar intake levels continued for several years.
— — Market basket tests
The government has conducting several “market basket” tests, though the most recent data we can find is from 2012. It covered 18 prefectures, including Fukushima. The samples were all commercially available food, from 13 food groups, with a focus on local fresh products. Over 200 food varieties were tested. The reports themselves are in Japanese, but a paper by Tsutsumi, et al, based on the 2011 MHLW market basket study is available. It includes an English abstract and many useful graphs, including fairly complete breakdowns in Bq/kg by food type and area studied:
March-August, 2011 MHLW market basket study (in Japanese)
September-November, 2011MHLW market basket study (in Japanese)
February-March 2012 MHLW market basket study (in Japanese)
September-October, 2012 MHLW market basket study (in Japanese)
Results summary:
— The annual radiation dose that would be received from eating food for an entire year that had the radioactive cesium levels found in food tested from September to October, 2012 (15 areas), is from 0.0009 ~ 0.0057 mSv/year. This dose is 0.6% or less of the 1mSv/year annual limit .
— The annual dose from K-40 is 0.14~0.22mSv/year, and is unaffected by the NPP accident.
— Highest doses are in Miyagi, followed by Iwate, Fukushima, Ibaraki, Tochigi
— Changes in dose from 2011–2012: see graph: — — Sept- Nov 2011: Cs = 0.0024–0.019 mSv/y — — Feb-Mar 2012: Cs = 0.0009–0.0094 mSv/y — — Sept-Oct 2012: Cs = 0.0009 ~ 0.0057 mSv/y
— Central Fukushima only: — — Sept- Nov 2011: Cs = 0.019 mSv/y — — Feb-Mar 2012: Cs = 0.0066 mSv/y — — Sept-Oct 2012: Cs = 0.0038 mSv/y
This indicates that the dose has been decreasing over time.
— Fukushima Pref. duplicate portion tests
Fukushima Pref. has also been conducting duplicate portion tests, but as has often been the case with prefectural data, their results have not been reported as informatively as they should be, though the 2013 report is slightly improved over the 2012 report. No 2014 report is available.
Report, Sept. 24, 2012 (link dead)
Report, Feb. 20, 2013 (link dead)
Summary of Feb. 2013 report:
This was the second duplicate portion survey done by Fukushima Pref.. 77 Fukushima residents participated from Sept-Nov 2012. The survey included households from 7 regions in Fukushima prefecture, with participants ranging in age from 0 to 70 years old. Each person saved an extra portion of all meals, including snacks and beverages, that he/she consumed for one day, and sent it to the testing center.
Cesium was detected in 56 samples, or 73%. The breakdown is as follows: — 21 samples ND (not detected) at a detection limit of 0.054–0.029 Bq/kg — 53 detected, less than 1 Bq/kg — 2 detected, between 1–2 Bq/Kg — 1 detected, more than 2 Bq/kg. (This person’s food showed 171 Bq/kg. This family habitually ate wild foods it gathered, such as mushrooms, as well as food it grew itself. )
— Minna no Data
Minna no data (“Everyone’s data”) is a joint searchable online database which combines food radiation measurements from approximately 20 citizens’ run labs in several prefectures. The site was launched in Sept. 2014, and new features gradually added. Both English and Japanese language are available:
Tested food items can be searched by prefecture, by food variety, by date tested, and a few other parameters. The base currently contains slightly over 10,000 items from all over the country. Of the 2337 tested samples from Fukushima, 57 had cesium detected, 8 were over 100 Bq/kg (0.34%). All others were ND. The over-limit rate for these samples is actually much lower than for official testing.
For Miyagi Pref., 45 of 1003 samples were over 100 Bq/kg (4.4%); almost all were mushrooms, and several of wild boar. This seems to reflect the fact that locals are concerned about these items and so the database includes many of them; also that many are in fact contaminated.
— CRMS
CRMS (Citizens Radioactivity Measuring Station) operates several food monitoring labs, in Nihonmatsu, Sukagawa, Tamura, Koriyama, and Tokyo (In late 2013, their former lab in Fukushima City was split off.)
Results page (in Japanese, but very readable with auto-translate):
Summary of results from 2013 (English press release; no more recent summary appears to be available):
Analysis of results (Japanese)
Brief take away:
Of 6886 items tested until 2013 from all over the country, 452 were (6.56%) were above 100Bq/kg. For Fukushima alone, 6126 items tested, 427 (6.97%) were above 100Bq/kg.
Higher percentages are reported for lower levels of contamination, such as 13.61% at 50Bq/kg for food from Fukushima. These samples include many homegrown items, and items which were not approved for sale and for which advisories have been in place since 2011, such as wild mushrooms, wild boar, etc.. This dataset may well represent what the contamination levels of the food supply would be like if no monitoring was being done.
— Greenpeace:
Greenpeace has conducted several food monitoring surveys, and results (in Japanese) can be found here:
The most recent survey including food measurement data is from June 2013. These surveys are usually not very large, a couple of dozen items each time. Some recent ones include:
— Fish samples caught at sea, which appears to have been done in collaboration with local fishermen. A recent report from June, 2013, has several samples from Tomioka, 10 km south of the plant, as well as from Chiba and other locations, 25 samples in all. The highest level found in this group was in a sea snail collected off Tomioka, at 90Bq/kg. Only 8 of the samples had detectable cesium.:
Greenpeace 20th Japan Monitoring report, June 2013
— Samples bought in supermarkets. The most recent test at the time of writing is from April, 2013, and includes 30 samples of seafood products which originated in Hokkaido, Iwate, Miyagi, Chiba, Mie, Wakayama, Hyogo, Tottori, Kagoshima, Oita, and Nagasaki, and had been purchased in supermarkets in Tokyo, Kanagawa, Osaka and Nara. Only two of the samples in this group had detectable cesium; the highest was a Pacific cod from Iwate, which had 7.4 Bq/kg:
Greenpeace Japan supermarket test results April, 2013
A handful of early Greenpeace food test reports in English from 2011 can be downloaded from this page. At the time these were released not much official information was available, and they helped fill the gap:
Greenpeace food test reports in English, 2011
Direct links to English language reports from 2011 (1)
Direct links to English language reports from 2011 (2)
(Thanks to Antonio Portela for his assistance in compiling this data. Some previously appeared on the FCCJ Number 1 Shimbun website)
(end of section 2.4)
TO OTHER SECTIONS:
2.1- Issues at Fukushima Daiichi Nuclear Powerplant (FDNPP)
2.3- Environment and Decontamination
2.4- Food
