Sunflowers to clean up radioactive soil at Fukushima

Sunflowers to clean up radioactive soil at Fukushima: "Sunflowers to clean up radioactive soil at Fukushima
After the 1986 Chernobyl nuclear disaster, sunflowers and rape blossoms were used to decontaminate soil in Ukraine. -- PHOTO: JOHN TAN

JAPANESE researchers who study space agriculture believe growing sunflowers will remove radioactive caesium from contaminated soil around the Fukushima No.1 nuclear power plant, and are planning a project to plant as many of the yellow flowers as possible this year.

They have invited people to sow sunflower seeds near the Fukushima Prefecture power station, hoping the sunflower will become a symbol of recovery in the areas affected by the nuclear crisis.

After the sunflowers are harvested, they will be decomposed with bacteria, according to a plan by a Japan Aerospace Exploration Agency group led by Professor Masamichi Yamashita. After the 1986 Chernobyl nuclear disaster, sunflowers and rape blossoms were used to decontaminate soil in Ukraine. Radioactive caesium is similar to kalium, a commonly used fertiliser. If kalium is not present, sunflowers will absorb caesium instead.

If the harvested sunflowers are disposed of by burning them, radioactive caesium could be dispersed through smoke, which is why the researchers are considering using hyperthermophilic aerobic bacteria - used to produce compost - to decompose the plants. The decomposing process will reduce the sunflowers to about 1 per cent of their previous volume, which will slash the amount of radioactive waste that needs to be dealt with.

The group has gathered about 300kg of sunflower seeds and has also asked Thailand, a major producer of sunflower seeds, for cooperation in the project. They also plan to ask high schools in and near the 30km zone around the Fukushima plant to grow sunflowers on their school grounds.

'We're still in the process of planning for the decomposition facility and some other things. Looking toward the autumn harvest, we'd like as many people as possible to join the project,' Prof Yamashita said. -- THE YOMIURI SHIMBUN/ANN

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