Frequently asked questions and answers about foods that contain radioactive materials.Question: What will happen if foods containing radioactive materials are consumed?
Answer: If radioactive substances contained in foods or water are consumed, they will remain in the body and continue emitting radiation. Emissions from the Fukushima nuclear facility of radioactive iodine-131, which has been found in milk, vegetables and water, has an eight-day half life--meaning it loses half of its radiation in eight days and three-quarters in 16 days. Similarly, iodine-131's radiation reduces steadily and does not remain on soil for long periods. Meanwhile, radioactive cesium-137 takes 30 years to lose half of its radiation. It will remain on soil for a longer time and affect agricultural products. However, even if cesium-137 is consumed, much of it will be excreted from the body.
Q: What do provisional limits mean?
A: Provisional limits are the amounts of radiation estimated to cause health hazards such as increased risk of cancer if a person consumes all the following foods containing radioactive materials every day for one year: one liter of milk or other dairy products, two liters of water and 100 grams of leafy and other vegetables, said Atsushi Kasai, former laboratory chief of the Japan Atomic Energy Research Institute. It is significant to note that your body will not be affected even if a food containing radiation at about 100 times the provisional limit is accidentally ingested just once.
However, this does not mean that you should eat foods containing more than the provisional limits of radioactive materials, Kasai said.
Q: How do radioactive substances attach to foodstuffs?
A: Yasuyuki Muramatsu, professor of Gakushuin University, who specializes in radiochemistry, said that radioactive iodine and radioactive cesium are carried by the wind and tend to attach to large leafy vegetables like spinach. They adhere to the surface of cabbage but will not easily make their way inside, Muramatsu said. Radiation levels can be lowered to a certain degree by washing vegetables well with clean water. It also is recommended that cabbage be washed after the outside leaves are removed.
Radioactive substances tend to stay on the soil surface and have only small effects on Japanese radish and other root vegetables in the short term, he added. Radiation was detected in cows' milk because dairy cows probably consumed feedstuff or water containing radioactive substances, Muramatsu said.
Q: How were the latest radiation tests conducted?
A: Each municipal government tested its principal and other products such as rice, vegetables, milk and seafood. In case of Ibaraki Prefecture, the prefectural government took samples in its northern region, which is closer to the Fukushima No.1 nuclear power plant, and areas with larger shipping volumes to test their products.
The Health, Labor and Welfare Ministry advised local governments to test vegetables after washing them so their radiation levels more closely approximate produce just before it is consumed.
Q: What are the effects of radioactive materials on children?
A: Children are more sensitive than adults to the effects of radiation. In case of an adult, about only 7 percent of radioactive iodine taken into the body is stored in the thyroid gland and the rest is excreted within 24 hours, said Gen Suzuki, professor of International University of Health and Medicine. On the other hand, a child's body retains about 20 percent. However, provisional limits are set at a safe level so that children will not be affected if they consume foods containing radioactive substances within the limits.
(Mar. 22, 2011)
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