(Subscription Only) Title: Worries over highly radioactive fish prompt study
Author: HIROSHI ISHIZUKA
Date: November 13, 2012
Persistently high radioactivity in some fish caught close to the Fukushima nuclear plant has sparked a government investigation into the physiological basis for contamination and why radiation readings in some specimens remain hundreds of times over the official safe limit.
[...] The overall trend has been a decline in detected amounts of radioactive cesium.
However, in August, two greenlings caught 20 kilometers north of the Fukushima plant were found to have cesium levels of 25,800 becquerels per kilogram, the highest level ever measured in fish since the nuclear accident. The government standard for food is 100 becquerels per kilogram.
And in March, tests recorded a level of 18,700 becquerels per kilogram in freshwater salmon in the Niidagawa river near Iitate [...]
The forthcoming study will analyze cesium levels in the fish’s otolith, a part of the inner ear. The otolith is widely used in such research because it is an organ where trace elements tend to accumulate over the animal’s lifespan, leaving a growth record that can be likened to the rings of a tree. [...]
Published: November 13th, 2012 at 7:09 am ET