Cesium from leaves stayed in soil

October 29, 2013

Study: cesium from plant staying in forest soil

http://www3.nhk.or.jp/nhkworld/english/news/20131029_40.html

A team of Japanese researchers says most of the radioactive cesium that was released from the crippled Fukushima Daiichi nuclear power plant and fell on forest soil remains there.

Researchers at the government-affiliated Japan Atomic Energy Agency installed monitoring equipment in woods of northern Ibaraki Prefecture, near Fukushima Prefecture, in May 2011, 2 months after the accident. They hoped to learn how the cesium moved from fallen leaves to soil.

The results of more than 2 years of research show that rain washed cesium off leaves 6 months after the accident, and that as the leaves decomposed, it moved to the surface of underlying soil.

The researchers found that only about 0.1 to 0.2 percent of the cesium went 10 centimeters deep into the ground each year.

They concluded that underground water very likely has not carried cesium from the soil to nearby areas.

Researcher Takahiro Nakanishi said the results suggest that the cesium has not gone deep underground. He said the findings would be useful in efforts to decontaminate affected areas.