lunedì 17 marzo 2014

Radioactive Fukushima Waters Arrive At West Coast Of America

Presenters at the annual Ocean Sciences Meeting of the American Geophysical Union in Honolulu in late February said ocean water containing dissolved radionuclides from Fukushima’s crippled nuclear reactors has reached the northern west coast of North America (msn.com).

The scientific community found it interesting in an academic way. Some folks in the non-scientific community were quite worried.
The amount of Fukushima radioactivity in this seawater is miniscule, about a Becquerel per cubic meter of water, or Bq/m3 of short-lived Cs-134, and poses no concern at all. And never will. By comparison, the EPA drinking water standard for it’s sister radionuclide, Cs-137, is about 7,400 Bq/m3, and for all radioactive materials is almost a million Bq/m3.
But since we can see a single atom disintegrating, we can detect this trace amount of radioactivity easily, way better than we can detect toxic compounds like mercury. This Fukushima rad-signature has already taken its seat alongside that left over from above-ground nuclear tests in the 1950s and 60s as a curious and interesting phenomenon we can use scientifically to track water and air circulation patterns, and to use in forensic oceanography.
But the Fukushima rad-concentrations are nowhere near as high as that left over from the old bomb tests, which are nowhere near as high as that of natural background. In fact, Fukushima’s rad-signature is so low that we need to separate the Cs-134 from the Cs-137 just to know it’s from Fukushima. Cs-134 has such a short half-life (2.1 years versus 30 years for Cs-137) that it has long decayed away from the old tests. The Cs-137 from Fukushima is so low it’s totally eclipsed by the leftover Cs-137 from the 50s and 60s.

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