Radioactive materials spread around northern hemisphere in 2 weeks

From Kyodo News :

" Radioactive materials released from Japan's crippled Fukushima Daiichi nuclear power plant had spread around the entire northern hemisphere in the two weeks following the March 11 quake and tsunami disaster, a Vienna-based international nuclear watchdog said Thursday.

The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization said minute traces of radioactive substances spread around the hemisphere by around March 25 after moving across the Pacific Ocean and other places. It said the amounts of such substances were far below levels that could affect human health.

The organization runs 63 monitoring stations around the world, including one in Takasaki, Gunma Prefecture in Japan. The Takasaki station detected radioactive substances on March 12, followed by detection in eastern Russia on March 14 and in the west coast of the United States two days later. The radioactive materials then crossed the Atlantic and reached Iceland on March 22, it said."