Last week Tepco announced that they had measured 1,000,000 Bq/m3 of Strontium-90 (nuclear radiation) at two locations in sea water near to Fukushima.
Strontium-90 is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 28.8 years.
The 1,000,000 Bq/M3 reading represents the highest reading in recorded history.
The full report can be read at: http://www.tepco.co.jp/nu/fukushima-np/f1/smp/2015/images/2tb-east_15061901-j.pdf
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