Tuesday, October 4, 2011

Tea and radiation in Japan

Even after the nuclear accident, I have not stopped drinking Japanese tea.  I understand that tea in the market is basically regulated and safe.

Konnichiwa, it’s Kohei(^^)  The other day, I attended a workshop about “Tea and radiation”.  It was lectured by Mr. Nakamura from the Shizuoka prefecture chagyo-kenkyu center (http://www.pref.shizuoka.jp/sangyou/sa-820/).  This workshop included some scientific information and technical data, and it was difficult for me to follow those parts.

However, the overall main idea is …

l  The radiation exists in our daily lives since before the incident and we are exposed to it at some level.  You can’t make it “0” zero. 

l  At the moment, nobody can tell that you'll get cancer just by the number of radiation you are exposed to.  What you can only say is that less is better.  The risk of getting cancer with radiation is quite the same as getting one by smoking.  You can’t exactly tell how many cigarettes does one have to take to develop cancer.

l  The government set a very low maximum contamination point for tea so most Japanese tea is perfectly safe.   It is indicated that tea can only have the maximum of 500 Bq/kg of radioactive cesium.  Anything beyond that is rejected.

One of the data that I was interested in was the difference of the regulation at each organization.  It appears that even on this date, Japanese regulation is quite strict among those organizations.

Regulation for radioactive cesium in tea

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1250500(since Apr8 2011)




3000 (Cs134:1000,  Cs137:2000)





This data is from the workshop.


  1. Please watch this and then talk about the safety of tea in Japan. There is virtually no printed news about this story on the internet, at least not in English, since about three months ago. This is a scary video. I am inclined to buy my green tea from China until someone does an open and honest study and publishes the results in terms that a layman can understand:


  2. Hi, thank you for the link of the video. I didn’t know about the contaminated tea over the limit found in France and a mail order company in Tokyo. I’ll write about it on the next post. Thanks!

  3. Thank you. I would appreciate hearing about anything you can find on this subject. I buy Ito En sencha in bags (with a little macha powder in there too), in the US, very good tea and very inexpensive considering the good quality of the tea. Their tea comes from Shizuoka and I am wondering about that youtube report about Shizuoka.

    I think your blog is very interesting and informative for Westerners who don't know very much about Sado or tea in Japan. I just discovered it yesterday and have read a lot of it already. Thanks. Your English is very good, too.