Primitive Technology

Why did scientists plant sunflowers after the nuclear disaster?

Just after lunch on March 11, 2011, a disaster struck the east coast of Japan.

A catastrophic 9-magnitude earthquake, followed by a massive tsunami, hit Miyagi and Fukushima prefectures, killing tens of thousands of people. Subsequently, the Fukushima Daiichi nuclear plant in Ōkuma suffered a series of explosions, releasing toxic radioactive waste into the surrounding environment.

Its consequences locally are still felt to this day, as Japan tries to find a way to deal with millions of tons of radioactive wastewater and huge amounts of solid waste. But among all the controversies and high-tech solutions, there is one radiation cleanup program that you may have overlooked, and that is the sunflower planting solution.

“We grow sunflowers, cabbages, amaranth, and periwinkle cotton, all of which are said to absorb radiation,” Koyu Abe, abbot at the nearby Joenji Buddhist temple, told Reuters a few months later. disaster. “We’ve grown at least 200,000 flowers so far… and are planting more seeds. At least 8 million sunflowers that have bloomed in Fukushima come from here.”

In fact, sunflowers do a great job of cleaning radioactive waste out of the environment – that’s why they were planted in the fields after the 1986 Chernobyl disaster.

Plant sunflowers near the nuclear disaster area
Sunflower seeds that grow in contaminated soil and plant areas will be safely collected and disposed of, but as they grow and bloom, they will create a vibrant yellow landscape that repels the mourning mood.

The double earthquake that claimed the lives of 23,000 people severely damaged the Fukushima plant, causing a radioactive leak for several months. Sunflowers are not only a beacon of hope and a symbol of rebuilding, but also absorb Cesi from radioactive soil. Sunflowers, rosemary leaves, and the like, were previously used for this purpose in environmental remediation at Chernobyl, Ukraine.

Soil scientist Michael Blaylock explained in a 2011 interview: “Sunflowers are really good at picking up certain radioisotopes.” “And that’s really the connection between sunflowers and nuclear power plants that we’re used to seeing today… some of the fallout from the Chernobyl incident was absorbed through the cultivation of sunflowers in places where sunflowers were grown. affected area”.

So why sunflowers? Sunflowers have a lot of practical properties that make them ideal for nuclear waste cleanup: they grow quickly, easily growing anywhere. They even store most of their biomass in the leaves and stems of the plant, so that the radioactive material absorbed by the plant can be processed without having to dig up the roots.

About 95% of the radioactive cesium is deposited between the ground and a depth of 2.5cm, while the roots of mature sunflowers penetrate more than 1m deep into the ground. The most effective way to remove radioactive material from soil is to remove the top layer of soil. According to experimental results, if you peel off the 3cm thick layer of soil where short-rooted grass grows, it will remove up to 97% of radioactive cesium. If the 4cm thick layer of soil is removed in normal areas, this radioactive material will be reduced by 74%. In the case of chemical hardening of the upper soil layer and removal of that layer, the amount of radioactive cesium in the soil is reduced by 82%.

Plant treatment, or the use of plants to remove toxins from the environment, was a huge success at Chernobyl, where the nuclear disaster left radioactive soil and water with radioactive elements cesium and strontium. . These radioisotopes have a structure that “mimics” the nutrients that sunflowers would naturally absorb so that the radioactive substances will be absorbed by the sunflower plant.

After the Chernobyl nuclear disaster on April 26, 1986, scientists used sunflower and rapeseed plants to reduce radioactivity in radioactive soil in Ukraine. Radioactive cesium (Cs) has properties similar to kalium (Ka), a common element in chemical fertilizers. In case the amount of Ka in the soil is not enough, sunflower plants will absorb Cs to grow.

Unfortunately, despite the success at Chernobyl, the plant remediation efforts at Fukushima were ultimately deemed failures. Not much is known about this experiment, but the few analyzes performed did not find any plants that could effectively reduce radioisotope levels in the soil.

To a certain extent, however, this is not surprising – there are simply too many differences between Fukushima and Chernobyl for the experiments to work out the same way.

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