PARIS - The plume from Fukushima has now reached the western Atlantic but its radioactivity is likely to be "extremely low" and have no impact on health or the environment, France's Institute for Radiological Protection and Nuclear Safety (IRSN) said on Saturday.
"As of yesterday, the cloud covered most of North America and northeastern Siberia. It is currently passing over the North Atlantic," it said, naming French terroritories in the Caribbean and off Canada's eastern coast.
The cloud has been progressively thinning as it heads eastwards around the northern hemisphere at high altitude and will reach mainland Europe on Wednesday or Thursday, it said, citing a computer model jointly compiled with the French weather service, Meteo France.
"The concentrations of caesium 137 in the air over land traversed by the plume are expected to be extremely low," it said.
In France, "these concentrations will be at a level that is too low to be detected."
Caesium 137 is a long-lasting radioactive contaminant that caused the worst environmental problems in the 1986 Chernobyl disaster.
"The IRSN shares the view of the US Environmental Protection Agency (EPA), which judges that these levels will have no impact on health and the environment," the agency said in a press statement.
"Furthermore, they will be so minimal that they will probably will only be detected in the environment by measuring samples carried out by specialised laboratories."
The map will be placed on the IRSN website (www.irsn.fr), it said.