Long Shadow of Chernobyl: 224 Bq/kg of Cesium-137 in the Ashes from
Burning Wood Pellets Made from Trees in Shikoku
Posted: 26 Apr 2013 12:02 AM PDT
And of atmospheric testing of nuclear weapons by world nuclear powers,
which did not stop until 1980 (China).
One of my twitter followers lives in southwestern Japan. A while ago he
sent me the result of the test he had it done with the ashes from
burning wood pellets in his stove this winter. The lab test, using the
germanium semiconductor detector, found *223.8 Bq/kg of cesium-137*.
He was upset, thinking it is from Fukushima I Nuclear Power Plant, until
I pointed out to him that *there was no cesium-134* found. The cesium in
the ashes is most likely from the fallout from atmospheric testing, and
the Chernobyl accident in 1986.
He burned 600kg of wood pellets made from cedar trees in Ehime
Prefecture in Shikoku Island in southwestern Japan. According to the
pellet manufacturer, the concentration factor was about 375, and
*radioactive cesium (Cs-137) in the pellets was estimated to be about
He said he will "entomb" the ashes with concrete and bury.
The chart plotting the historical monthly fallout in entire Shikoku (4
prefectures, as they didn't start measuring the fallout in Ehime until
1977) shows the spike from the Chernobyl accident was less than that of
the atmospheric testing, and larger than that from the Fukushima
accident. (The chart was created from data at Japan Chemical Analysis
>. Y-axis in log scale.)
In 2012 he tested the ashes from burning the wood pellets from a
different company, and to his great dismay the test found *1,000 Bq/kg
of radioactive cesium (Cs-137)* in the ashes. He had already spread some
of those ashes on his home garden. *Those pellets, it turned out, were
made from trees from Europe* (Sweden, Finland, Germany, Austria) that
the manufacturer had started to purchase in 1994 . That manufacturer
told him that it had never ever occurred to them that the trees were
contaminated from the Chernobyl accident, and there was no regulation on
importing. The manufacturer told him that *they chose European trees
because they were cheap, and supply was steady*.
April 26 marks the 27th anniversary of the Chernobyl Nuclear Plant accident.
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