Five and half years after the Tohoku earthquake and subsequent meltdown of the Fukushima Daiichi Power Plant in Japan, a question still lingers for some tea enthusiasts:

Is Japanese tea safe to drink?

The short answer?

Yes.

The longer answer?

Resoundingly, yes!

And the reason why is multi-faceted.

Firstly, by “safe to drink”, the layman might think this means, “the tea is absent from radioactive particles”. While this may be true for many producers, this interpretation isn’t entirely accurate, for reasons that will soon become apparent.

Why shouldn’t you be worried? Thankfully, radiation doesn’t travel far unless carried by a radioactive material, and the tea growing regions of Japan are a significant distance from Fukushima. The distance from Fukushima to Shizuoka Prefecture, where 40% of all Japanese tea is grown, is 360 km (224 miles), or just a bit further than the distance from New York City to Washington D.C. Another 30% is grown on a completely different island, Kyushu, where you have the infamous tea growing Prefectures Fukuoka and Kagoshima, the latter of which is as far away from Fukushima as New York City is from Atlanta. It’s worth noting that the exclusion zone around the power plant is only 30 km (18 miles), and over the last five and a half years, the Japanese government has been systematically removing a layer of topsoil, significantly reducing the ambient background radiation.

[Before continuing, let’s clarify two different and useful scientific terms that measure radiation: the becquerel (Bq) and the sievert (Sv). Becquerel measures how much radiation a substance emits. Sievert, usually measured as a millisievert (mSv), measures how radiation effects the body.]

Before Fukushima, Japan allowed food exports to register under 500 Bq / Kg, the same limit as the European Union. After the disaster, Japan reformed their rules to only allow 100 Bq / Kg, the lowest range of any country on Earth. You might be wondering, as a means of comparison, how much does the USA allow in our imports? Even though Canada and the International Codex allow a maximum of 1000 Bq / Kg, the United States tops the list with a maximum of 1200 Bq / Kg, or 12 times Japan’s standard!

Though this seems high (by comparison), we are far from negligent in our duties. The FDA has worked on this issue extensively, coordinating with Japan’s Ministry of Health, Labour, and Welfare (MHLW), and issues reminders to the public that it has found no cause for concern among any imported foods from Japan and that the import standards are considered safe. They also consult the EPA’s environmental radiation monitoring program (RadNet), and the International Atomic Energy Agency (IAEA), who keep a fairly regular (weekly to bi-weekly) journal of what’s happening in Japan.

Provided these organizations are doing their jobs, many tea companies have taken up the mantle of preventative concern themselves. For instance, Aiya, a huge Japanese brand primarily selling matcha, releases monthly reports of radiation testing conducted on their tea, a process that certainly doesn’t come cheap. Numerous other brands do this, and are very open about the testing. Resources are available online to research what levels of radiation are being reported in Japanese foodstuffs and tea, either from governmental bodies or from the tea distributors themselves. If you’re concerned, simply ask!

Finally, there’s the idea of “safe” when it comes to radiation. All of these numbers and concepts can be abstract, so I’d like to provide context.

Let’s perform a thought experiment based on a worst-case scenario:

  • Let’s say that you’ve purchased a Japanese tea that has registered the maximum legal export limit in Japan = 100 Bq / Kilo. (Remember that this is still 1/12 the United State’s limit on imports.)
  • Then, let’s say you drink three cups of tea a day for a whole year, using an average of 4 grams of tea per cup. This translates to 12 grams of tea, or 1.2 Bq, per day.
  • Let’s really shake it up! When you steep dry tea leaves, very little radioactive material enters your cup; only between 2% and 10%, depending on the study and conditions you reference. Instead, let’s pretend that you’re actually just eating the tea, thereby consuming 100% of the radioactive material present, as you would when you make matcha. (Although 12g of matcha a day is about 420 mg of caffeine, or nearly 7 shots of espresso, enough to drive even die-hard caffeine lovers up a wall.)

Taking all these factors into consideration, what would be the total amount of radiation you would ingest over the course of a year?

About 29 bananas.

* Yes, bananas are radioactive, because about 0.0117% of natural potassium is radioactive, thus any foodstuff with potassium, including avocados, potatoes, beans, and yes, coffee (don’t get too excited tea people), are radioactive.

The simple  and unavoidable fact of life is this: we’re all exposed to radiation constantly. It’s a natural part of this planet. It’s everywhere, bombarding us from space, radiating from the building materials of our homes, from minerals in the soil, and in the air we breathe. This is called background radiation. Ever been in a hot spring? Been near a brick or cement building? Flown in an airplane? Been to the dentist? Then you’ve been exposed to multiple forms of radioactive materials. The average human on this planet racks up about 2 to 4 mSv of background radiation a year (and in some places this can be as high as 10 mSv). The experiment detailed above, an exaggerated worst-case scenario, would be effectively the same as walking around the Colorado Plateau for a day or two.

The longer answer summarized into a tasty, bite-sized take away:

Japan and their tea producers took the necessary, often extreme precautions, in coordination with multiple organizations at home and abroad, to make sure their tea was safe for you and me. Radiation is everywhere and the amount you could possibly get from drinking tea is minuscule. So stop worrying about it and go enjoy a cup!

References:

http://www.foodsafetymagazine.com/magazine-archive1/octobernovember-2011/japanese-tea-plan-b/

https://www.o-cha.com/green-tea-radiation-info.html#certificate_of_radiation

http://www.nytimes.com/2015/09/22/science/when-radiation-isnt-the-real-risk.html?_r=1

http://www.matchareviews.com/faq-should-i-be-worried-about-radiation-in-my-matcha/

http://news.mit.edu/2011/explained-radioactivity-0328

https://www.iaea.org/newscenter/focus/fukushima/status-update

http://www.fda.gov/NewsEvents/PublicHealthFocus/ucm247403.htm

http://www.mhlw.go.jp/english/topics/2011eq/index_food_radioactive.html

http://www.teamuse.com/article_110701.html

https://www.worldnomads.com/travel-safety/eastern-asia/japan/how-dangerous-is-the-radiation-in-japan

http://www.forbes.com/sites/jamesconca/2013/01/11/like-weve-been-saying-radiation-is-not-a-big-deal/#4e1782a84c34

http://www.world-nuclear.org/information-library/safety-and-security/radiation-and-health/radiation-and-life.aspx

https://www.epa.gov/radnet

Photo Credit: https://commons.wikimedia.org/wiki/File:Tea_Plantation_in_Nansatsu_Plateau.jpg