39
Agricultural Measures for Reducing Radionuclide Contamination of Agricultural Products in Japan July 2015
Agricultural Measures for Reducing Radionuclide Contamination of Agricultural Products in Japan
July 2015
Table of Contents 1. Measures taken to ensure distribution of safe foods 2. Measures and monitoring results of each commodity 2.1 Vegetables 2.2 Fruits and tea 2.3 Rice, soybeans and buckwheat 2.4 Livestock products 2.5 Cultivated mushrooms 2.6 Edible wild plants, wild mushrooms and
wild game meat 2
1. Measures taken to ensure distribution of safe foods
3
Measures taken to ensure distribution of safe foods
Restriction on planting
Measures to reduce radionuclides in agricultural products
Sampling and testing
Restriction of distribution
When violations are found in two municipals or more in a prefectural area
Analysis of contamination factors
4
To ensure food safety, distribution of products with radioactive levels exceeding the limits are prevented through (1) reduction measures for radionuclides at farm lands, (2) testing of radioactive cesium before shipment, and (3) restriction of distribution according to testing results.
The limits have been established on the basis of :
Intervention exemption level of 1 mSv/year (same as Codex GLs)
50% of contamination rate
Standard limits for radiocesium concentration in foods
134Cs+137Cs (Bq/kg) General foods 100
Milk 50 Infant foods 50
Drinking water 10 5
17 prefectures Sampling methods for each commodity
Guidelines for sampling and monitoring Prefectural governments carry out monitoring of foods based on the guidelines provided by the Nuclear Emergency Response Headquarters.
Year Total number of samples except for rice produced in Fukushima since 2012*
2011 137,037
2012 278,275*
2013 335,860*
2014 (as of July,2015)
314,216*
Note: All rice produced in Fukushima has been screened since 2012. The number of rice bags screened each year amounts to more than 10 million.
• Vegetables and fruits • Milk • Tea
• Fish/Crustaceans • Wheat • Beef
• Rice • Soybeans and buckwheat • Mushrooms
6
Most of the radiocesium is present in a surface soil layer.
Topsoil is interchanged with subsoil to keep it out of reach of plant roots.
Removal of topsoil Reversal tillage
Decontamination of farmland
7
Experimental removal of topsoil
Ambient dose level（Surface） Before: 7.1 μSv/h After: 3.4 μSv/h （52％ Reduction） After harvest: 1.9μSv/h
Radioactive Cs in soil Before: 10,370 Bq/kg After: 2,599 Bq/kg (75％ Reduction )
Radioactive Cs in husked rice cultivated after decontamination: 20 Bq/kg
Neighboring field without decontamination: 5.7 μSv/h 8
Measures for fertilizers
The Ministry of Agriculture, Forestry and Fisheries (MAFF) has established reference value of radioactive cesium for fertilizers, soil conditioners and nursery soil : 400 Bq/kg.
This value is intended to ensure fertilizers
with radioactive cesium do not increase concentration of radioactive cesium in soil even after the long-term use of the fertilizers.
9
2.Measures and monitoring results of each commodity
10
Fallout Uptake from soil
Leafy vegetables Fruit trees/Tea trees
Pathways of radionuclide contamination of crops
11
2.1 Vegetables
12
99.9% (16,697）
0.09% (15)
0% (0)
0% (0)
0% (0)
0102030405060708090
100
FY 2014 （16,712 samples）
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in vegetables
13
Rat
e of
sam
ples
(%)
Radioactive cesium (Bq/kg)
• Samples exceeding the limit were reported from some vegetables which were being cultivated at the time of the accident.
• No samples have exceeded the limit since 2013.
99.9% (1,643)
0.06 (1)
0% (0)
0% (0)
0% (0)
0102030405060708090
100
FY 2015 （as of May 25) （1,644 samples）
99.8% (19,623)
0.2% (32)
0.01% (2)
0% (0)
0% (0)
0102030405060708090
100
FY 2013 （19,657 samples）
2.2 Fruits and tea
14
Measures to reduce radionuclides of fruit trees
The levels of radioactive cesium deposited onto above-ground parts of fruit trees have been reduced by cleaning the surface of bark with high-pressure water.
High-pressure washing of peach trees Decontamination of
persimmon trees in winter
15
4.2
1.3
0.1 0.6
0.2 0 0.0
1.0
2.0
3.0
4.0
5.0
上部 側部 下部
Rad
iatio
n co
untin
g ra
te (k
cpm
) はく皮前 はく皮後
• As for fruit trees whose bark can be removed with no substantial damage (e.g., grape, pear, apple and persimmon) , the surface of bark was scraped away.
• The radioactive dose of pear trees can be reduced by 90% by scraping the surface of bark.
Radioactive dose of pear trees before and after scraping bark
Scraping bark
16
Measures to reduce radionuclides of fruit trees
Before scraping After scraping
Upper parts Lateral parts Lower parts
100% (52)
0% (0)
0% (0)
0% (0)
0% (0)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2015 (as of May 25) (52 samples)
97.4% (4,134)
1.9% (81)
0.6% (26)
0.05% (2)
0% (0)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2013 (4,243 samples)
No samples have exceeded 100 Bq/kg since 2013.
17
Rat
e of
sam
ples
(%)
Radioactive cesium (Bq/kg)
99.1% (3,271)
0.9% (29)
0.06% (2)
0% (0)
0% (0)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2014 (3,302 samples)
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in fruits
Measures to reduce radionuclides of tea trees
To prevent the transfer of radioactive cesium from leaves and branches to new leaves, leaves and branches were plucked or pruned further than in usual practice.
Before pruning
After pruning
18
Ground Collar pruning
Medium pruning Deep plucking
Plucking
100% (36)
0% (0)
0% (0)
0
10
20
30
40
50
60
70
80
90
100
～5 5～10 10～
FY 2015 (as of May 25) (36 samples)
100% (206)
0% (0)
0% (0)
0
10
20
30
40
50
60
70
80
90
100
～5 5～10 10～
FY 2014 (206 samples)
99.6% (445)
0.4% (2)
0% (0)
0
10
20
30
40
50
60
70
80
90
100
～5 5～10 10～
Radioactive cesium (Bq/kg)
FY 2013 (447 samples)
19
Rat
e of
sam
ples
(%)
No samples have exceeded 100 Bq/kg since 2013.
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 5 Bq/kg.”
Summary of measurements for radiocesium in tea products
2.3 Rice, soybeans and buckwheat
20
y = 1673.2e-0.164x R² = 0.6243
0100200300400500600700800900
1000110012001300
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Levels of exchangeable K2O in soil (mg/100g)
Leve
ls of
radio
activ
e Cs i
n bro
wn ric
e (Bq
/kg)
Average in Fukushima City
(15.9 mg/100g)
National Average (28.5 mg/100g)
Measures for rice, soybeans and buckwheat : Application of potassium
• Soil in paddy fields where rice with high-level radiocesium was produced tend to contain low-level potassium.
• Having similar chemical characteristics to cesium, potassium in soil can suppress absorption of cesium by root uptake.
Fertilizing potassium
21
Potassium fertilizer are applied to control cesium absorption in rice, soybeans and buckwheat.
Restriction of rice planting
22
year area
2011 - Rice paddy fields where the concentration of radioactive Cs in soil exceeded 5,000 Bq/kg
2012 - Rice paddy fields where rice with radioactive Cs above 500 Bq/kg was produced in 2011 - Evacuation areas
2013 - Evacuation areas Note: Restriction in other areas was lifted according to testing results of rice of pilot planting, which were complied with the limit.
2014 - Evacuation areas where it is expected that residents will have difficulties in returning for a long time
Rice is a staple food in Japan and rice planting has hence been restricted in areas where highly contaminated rice could be produced.
Screening of all rice bags produced in Fukushima All rice bags produced in Fukushima have been subject to screening since 2012 .
Bags are approved for shipment only when they
pass screening levels.
Each rice bag is labeled with a barcode linked to its producer
before screening.
All bags are screened for possible contamination.
A Label placed after screening A bar code with producer’s information
Sample image
*Bags of brown rice
23
Screening results can be checked with QR codes on
their labels.
The number of samples exceeding the limit has been decreasing year by year.
24
Year Total number of samples
Number of samples >100 Bq/kg
% of samples >100 Bq/kg
2011 26,464 592 2.2
2012 10,375,002 84 0.0008
2013 11,042,971 28 0.0003
2014 (as of July 2015) 10,998,630 2 0.00002
Summary of measurements for radiocesium in rice
96.6% (2,112)
2.9% (63)
0.4% (9)
0.05% (1)
0.09% (2)
0102030405060708090
100
FY 2014 (2,187 samples)
94.8% (4,473)
3.5% (167) 0.8%
(38) 0.4% (18)
0.5% (21)
0102030405060708090
100
FY 2013 (4,717 samples)
0102030405060708090
100
FY 2012 (5,633 samples)
78.9% (4,445)
15.5% (871)
2.7% (150)
1.9% (106)
1.1% (61)
Radioactive cesium (Bq/kg)
Rat
e of
sam
ples
(%)
25
The number of samples exceeding the limit has been decreasing year by year.
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in soybeans
99.2% (1,415)
0.6% (9)
0.07% (1)
0.1% (2)
0% (0)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2013 (1,427 samples)
No samples have exceeded 100 Bq/kg since 2013.
Radioactive Cesium (Bq/kg)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2012 (2,918 samples)
6.6% (192) 2.2%
(64) 0.7% (21)
0.5% (14)
90.0% (2,627)
26
Rat
e of
sam
ples
(%)
99.9% (847)
0% (0)
0% (0)
0.1% (1)
0% (0)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2014 (848 samples)
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in buckwheat
2.4 Livestock products
27
Measures for livestock products : feed management
28
• Radionuclides can be transferred to livestock products by an animal’s ingestion of feed.
• Reference values for feed have been established to ensure that livestock products are complied with the limits for food.
Reference values for feeds (Bq/kg)
Cattle 100 Pigs 80
Chickens 160 Cultured fish 40
100% (210)
0% (0)
0% (0)
0102030405060708090
100
～25 25～50 50～
FY 2015 (as of May 25) (210 samples)
100% (1,846)
0% (0)
0% (0)
0102030405060708090
100
～25 25～50 50～
FY 2014 (1,846 samples)
100% (2,040)
0% (0)
0% (0)
0102030405060708090
100
～25 25～50 50～
FY 2013 (2,040 samples)
Although samples with radiocesium exceeding 50 Bq/kg were found in the aftermath of the accident, no samples have exceeded the limit since April 2011.
29
Rat
e of
sam
ples
(%)
Radioactive cesium (Bq/kg) Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in raw milk
100% (29,460)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2015 (as of May 25) (29,460 samples)
0% (0)
100% (186,937)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2014 (186,937 samples)
99.9% (193,262)
0.003% (6)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2013 (193,268 samples)
Rat
e of
sam
ples
(%)
Radioactive cesium (Bq/kg)
• In 2011, some samples showed levels exceeding 100 Bq/kg due to highly contaminated feed.
• No samples have exceeded the limit since 2013.
30 Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 50 Bq/kg.”
Summary of measurements for radiocesium in beef
100% (66)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2015 (as of May 25) (66 samples)
100% (781)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2013 (781 samples)
100% (629)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2014 (629 samples)
No samples have exceeded the limit since 2013.
31 Radioactive cesium (Bq/kg)
Rat
e of
sam
ples
(%)
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 50 Bq/kg.”
Summary of measurements for radiocesium in pork
100% (551)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2014 (551 samples)
100 % (705)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2013 (705 samples)
Radioactive cesium (Bq/kg)
Rat
e of
sam
ples
(%)
32
100% (56)
0% (0)
0% (0)
0102030405060708090
100
～50 50～100 100～
FY 2015 (as of May 25) (56 samples)
No samples exceeding the limit has reported, because chicken and eggs are generally fed with imported feed.
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 50 Bq/kg.”
Summary of measurements for radiocesium in chicken and eggs
2.5 Cultivated mushrooms
33
MAFF has established reference values for radiocesium concentrations in materials used for mushroom cultivation such as logs and spawn beds.
Logs to cultivate mushrooms are decontaminated before using if necessary.
MAFF has provided mushroom producers with guidelines and instructions on cultivation techniques to prevent contamination.
Measures for cultivated mushrooms
34
Reference values
Raw logs for cultivation 50 Bq/kg Media for mushroom beds* and mushroom beds 200 Bq/kg
Note: Mushroom beds are sawdust culture media with mushroom spawn planted.
100% (72)
0% (0)
0% (0)
0% (0)
0% (0)
0102030405060708090
100
FY 2015 (as of May 25) (72 samples)
99.4% (825)
0.6% (5)
0% (0)
0% (0)
0% (0)
0102030405060708090
100
FY 2014 (830 samples)
99.3% (863)
0.7% (6)
0% (0)
0% (0)
0% (0)
0102030405060708090
100
FY 2013 (869 samples)
35 Radioactive cesium (Bq/kg)
Rat
e of
sam
ples
(%)
No samples of Shiitake mushrooms grown on beds have exceeded the limit since 2012.
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in shiitake mushrooms grown on beds
94.6% (424)
4.7% (21) 0.7%
(3) 0% (0)
0% (0)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2015 (as of May 25) (448 samples)
86.9% (1,734)
11.2% (224) 1.3%
(25) 0.5% (10)
0.2% (3)
0102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2014 (1,996 samples)
72.3% (939)
21.4% (278)
5.2% (68) 0.8%
(11) 0.2% (2) 0
102030405060708090
100
～25 25～50 50～75 75～100 100～
FY 2013 (1,298 samples)
36
Rat
e of
sam
ples
(%)
Radioactive cesium (Bq/kg)
• No samples exceeded 100 Bq/kg in FY2015. • Distribution of mushrooms grown on logs have been restricted in
several prefectures as of May 25,2015. - Outdoor cultivation: 6 prefectures (93 municipalities) - Indoor cultivation: 4 prefectures (17 municipalities)
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in mushrooms grown on logs
91.1% （1,851)
4.9% (100) 1.8%
(37) 0.8% (16)
1.4% (29）
0
10
20
30
40
50
60
70
80
90
100
～25 25～50 50～75 75～100 100～
FY 2015 (as of May 25) (2,033 samples)
85.9% （3,061)
8.1% (289) 3.1%
(110) 1.1% (40)
1.7% (62）
0
10
20
30
40
50
60
70
80
90
100
～25 25～50 50～75 75～100 100～
FY 2014 (3,562 samples)
81.7% (2,602)
8.9% (282) 3.2%
(102) 1.8% (56)
4.5% (142)
0
10
20
30
40
50
60
70
80
90
100
～25 25～50 50～75 75～100 100～
FY 2013 (3,184 samples)
Rat
e of
sam
ples
(%)
Radioactive cesium (Bq/kg)
37
The number of samples exceeding the limit has been decreasing every year.
Notes: - Numbers in parentheses are total numbers of samples tested in each fiscal year. - Samples with values below limits of detection fall into the category of “~ 25 Bq/kg.”
Summary of measurements for radiocesium in edible wild plants
2.6 Edible wild plants, wild mushrooms and wild game meat
38
Measures for edible wild plants, wild mushrooms and wild game meat
Samples of edible wild plants, wild mushrooms and wild game meat tend to show higher concentrations of radiocesium than cultivated agricultural products.
Collection and distribution have been restricted in areas where highly contaminated foods can be found on the basis of monitoring results.
39
Items Areas where restrictions have been in place (as of May 25,2015)
Edible wild plants 7 prefectures (102 municipalities)
Wild mushrooms 10 prefectures (109 municipalities)
Wild game meat 9 prefectures (314 municipalities)
