# Record cesium level detected in fish caught near Fukushima nuclear plant

Kyodo

Tokyo Electric Power Co. said Friday it detected a record 740,000 becquerels per kilogram of radioactive cesium in a fish caught in waters near the crippled Fukushima Daiichi Nuclear Power Station, equivalent to 7,400 times the state-set limit deemed safe for human consumption.

The greenling measuring 38 cm in length and weighing 564 grams was caught near a water intake of the four reactor units in the power station’s port on Feb. 21 during the utility’s operation to remove fish from the port.

Tepco has installed a net on the sea floor of the port exit in Fukushima Prefecture to make it hard for fish living near the sediments of contaminated soil to go elsewhere.

According to Tepco, the previous record of cesium concentration in fish was 510,000 Bq/kg detected in another greenling captured in the same area. Currently, fishermen are voluntarily suspending operations off the coast of the prefecture except for experimental catches.

• Richard Batty

I did the math and this fish is the equivalent to 23 kg BED. That is 23 kg Banana Equivalent Dose.

A banana contains naturally occurring potassium-40. Each banana releases 31 bq/g, so 740,000/(1000*31)=23 kg.

I guess bananas are banned in Japan for exceeding state set radiation limits.

• CBGoodBuddy

The Japanese limit for food appears to be 1 Bq per gram. A banana with a typical weight of 120 grams has about a half a gram of natural potassium, which has an activity of about 31 Bq per gram of potassium. But the potassium is spread throughout the 120 gm banana, not concentrated. So that’s (31 Bq/gm * 0.5 gm)/(120 gm) = 0.13 Bq/gm, which is under the safety limit.

• Vincent BOUCHIAT

Well your calculation is false ! please check ! Banana releases 0.1 bq/g ,( 300 times smaller value than what you claim) so this fish is equivalent to 7,400 kg BED… a more significant value indeed

• Joseph A. Mungai

I imagine there’s worse problems eating that many bananas in one sitting.

• Charles Younger

Potassium-40 and cesium 134/137 behave very similarly in the human body with one notable difference which is the reason why the validity of the Banana Equivalent Dose has been challenged. The amount of potassium in the human body stays fairly constant because of homeostasis. That is, any excess absorbed from food is quickly compensated by the elimination of an equal amount.

http://en.wikipedia.org/wiki/Banana_equivalent_dose