Presentation from Safecast: The Next Three Years symposium, March 15, 2014

1. List of main reasons of why radioactive cesium is detected from food
A. The detected amount of cesium is proportional to its density in the soil
However the contamination amount is different by many reasons.
B. High level of contamination by concentrated radioactive materials
When the contamination is highly concentrated, there are higher possibility of food high
level contamination as well
1. Directly exposed to radioactive materials (especially absorbed by surface in March 2011)
Example: Citrus, tea leaves and wheat cropped in 2011
2. Seeds and leaves of perennial plants (especially evergreen trees) etc.
Example: Plums, citrus, tea leaves, chestnuts and kiwis
3. Foods that are high in potassium
Example: bamboo shoot, tea leaves, rice bran, soya beans, herb,edible wild plants and so on.
4. Foods that grow in non-clay soil
Example: all kinds of mushrooms and buckwheat (plant in Kuroboku-soil)
5. Foods that grow in acid soil
Example: buckwheat, blue berries that grow in peat moss
6. Exchange between ammonium and cesium (beans’ root nodule bacteria, ammonium
fertilizer)
Example: Soya beans
7. Foods that grow inside soil (Many of them are not contaminated, or low contaminated)
Example: Sweet potatoes
8. Foods that grow in water or mad (example:Rice that grew in water which contained
0.1Bq/L was contaminated as 76Bq/kg)
Example: rice, lotus root
9. Foods that have shallow roots (cesium have higher contamination in the surface layer)
Example: edible wild plants, herbs
10. Wild plants and animals that eat them
Example: edible wild plants, mushrooms, moss, deer and wild pig
11．Foods that grow in immature compost
Example: bamboo shoot
12.Seafood inhabit in the bottom of coastal area, they make an excursion in highly
contaminated areas and also they are on top of the food chain
Example: madara cod ,flatfish and so on
13.Freshwater fish contains minerals therefore they contain cesium easily
Example: most kinds of freshwater fish
(This document was made by KODOMOMIRAI Radiation Measuring Center)