Japan’s top government spokesman on Tuesday expressed deep concern over the detection of highly toxic plutonium in soil at the crippled Fukushima Daiichi nuclear power plant, calling for enhanced monitoring of data.
“The situation there is very serious,” Chief Cabinet Secretary Yukio Edano told a press conference.
“The current level does not pose a threat to human health, but we need to step up monitoring of data and do our utmost efforts to contain the damage. If higher levels of plutonium are found, we will apply necessary measures,” Edano said.
Plant operator Tokyo Electric Power Co. (TEPCO) said Monday evening that it has detected low levels of plutonium in soil samples collected on March 21 and 22 in five locations at the plant, the latest piece of bad news in Japan’s ongoing nuclear crisis. The traces of plutonium further suggest some of the radioactivity is coming from damaged reactor fuel rods. But the extent of the damage is unknown.
Plutonium, produced as a result of uranium fission, is more toxic than other radioactive substances such as iodine and cesium.
Radioactivity from plutonium can be shielded by a sheet of paper, but it can remain in lungs and other organs to cause long-term damages including cancer.
A magnitude 9.0-quake and ensuring tsunami on March 11 destroyed vital emergency cooling functions in the Fukushima nuclear complex, 230 km north of Tokyo.
Three of the complex’s six reactors are believed to have partially melted down and TEPCO is struggling to restart the facility’s own cooling systems using outside power. Workers continued efforts on Tuesday to remove highly contaminated water in the basements of the three reactors at the plant.
Meanwhile, the government’s Nuclear and Industrial Safety Agency said Tuesday it has ordered TEPCO to strengthen monitoring of trench water linked to the No. 2 reactor.
The utility detected radiation exceeding 1,000 millisieverts per hour in water in an underground tunnel for the No. 2 reactor on Sunday, adding to fears that radioactive liquid is seeping into the environment.
It has also detected radiation of more than 1,000 millisieverts per hour in water at the basement of the No. 2 reactor’s turbine building.
A single dose of 1,000 millisieverts causes temporary radiation sickness such as nausea and vomiting. A dose of 5,000 millisieverts would kill about half those receiving it within a month.