LOS ANGELES (Kyodo) — A small amount of radioactive sulfur released from Japan’s crisis-hit Fukushima Daiichi nuclear power plant has been detected on the U.S. west coast, a team of U.S. researchers said Monday.
But the researchers said it poses no threat to human health.
The team from the University of California, San Diego, announced the findings Monday in the Proceedings of the National Academy of Sciences of the United States of America.
The researchers detected two kinds of sulfur oxide, both of which contain radioactive sulfur-35.
The higher-than-normal level of radioactive sulfur-35 was detected at an atmospheric observatory near San Diego between late March and early April.
The density peaked on March 28 to hit an all-time high of two to three times the level normally seen at the observatory, U.S. media reports said.
The research team believes chlorine in seawater reacted with neutron and generated radioactive sulfur-35, which was released into the atmosphere together with steam and carried to the west coast by westerly winds.
Trace amounts of radioactive substances, such as radioactive iodine, believed to have come from the Fukushima Daiichi nuclear power plant, have already been detected in many parts of the United States.
In California, these radioactive substances have been detected in milk.
The Fukushima Daiichi nuclear power station was damaged by the March 11 earthquake and tsunami that devastated coastal regions of northeastern Japan.