If the old testing method is used, this tea could contain 2,400 Bq/kg of radioactive cesium in dry leaves.
The other sample from Kanuma City in Tochigi Prefecture also exceeded the new safety limit for brewed tea (10 Bq/kg), with 12 Bq/kg of cesium.
Checking the Kanuma City’s website, there is no mention of this test result, even though it was in the news on May 18, 2012 (Shimotsuke Shinbun). Instead, the page for Kanuma’s agricultural products has this interesting mention of how to take care of the tea plantations while the shipment of the tea from the city is halted (it has been halted since June last year, after the fresh leaves of tea from the city tested above the provisional safety limit):
Management of the tea plantations
It is considered desirable to do as you have normally done. As for the tea leaves and branches that have been pruned, there is no problem burying them in the farm land.
I believe many tea growers in Kanto did the deep pruning after their tea was found with high radioactive cesium last year. But if they buried the contaminated cuttings in the soil, they may have simply (re-)introduced radioactive cesium in soil which has been absorbed by the tea plants.
There are people (including Professor Hayakawa of Gunma University) who are speculating that radioactive cesium in green tea this year is the result of strong winds in spring that have blown dust particles off the land which landed on the tea leaves. And there are people who argue radioactive cesium was absorbed through the surfaces of old leaves and sent to the roots, so it is now in the tea plants.
In case of Kanuma City, it may have been absorbed from the roots, in addition to the absorption from old leaves from last year.
To freshen up your memory, Kanuma City in Tochigi Prefecture was the one that fed elementary school children with local beef last October as a PR stunt to prove how safe their beef was. More recently, the city’s mayor is very eager to accept the ashes from disaster debris incineration because the national government would foot the bill for upgrading the city’s aging final disposal site that needs major repairs.