The Yomiuri Shimbun reported earlier today:
The Forestry Agency will start checking for radioactive substances in cedar pollen in Fukushima Prefecture as early as next month in response to the crisis at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant, the agency said.
There is very little data in Japan or elsewhere in the world about pollen from plants grown in areas with high levels of radiation. If high levels of pollen-borne radiation are found, the Environment Ministry plans to release the data at the end of this year together with its forecast of the expected amount of cedar pollen to be dispersed in the air next spring.
The agency plans to pick male cedar flowers in the no-entry zone and check them for radioactive cesium, it said.
“As it will be the first such survey, we honestly don’t know how much we will find. We’d like to obtain objective figures by making an accurate survey,” an official of the agency said.
Pollen can be carried great distances by the wind, says the paper:
According to the Social Welfare and Public Health Bureau of the Tokyo metropolitan government, the wind sometimes carries cedar pollen more than 200 kilometers.
“It depends on the velocity and direction of the wind. Pollen is said to fly from dozens to hundreds of kilometers. When a survey was conducted by helicopter, pollen was found as high as 5,000 meters in the air. It is highly likely that pollen from Fukushima Prefecture reaches the Tokyo metropolitan area,” said Norio Sahashi, a visiting science professor at Toho University and an authority on pollen.