Thursday, June 7, 2012

Radiation on the Move

Radioactive materials have a nasty habit – they like to travel.  This phenomenon has caused panic at various times in history after nuclear events and accidents, and continues to do so these days. The nuclear disaster at Chernobyl created clouds of radioactive dust that swept across great swaths of Eastern Europe. Because most of the radiation was leaked into the environment when explosions and resulting fires destroyed the plant, the particles carrying radioactive material were very small and were carried easily by weather patterns. With little warning and even less monitoring, thousands were exposed to unknown amounts of radiation.

As the cleanup of the Fukushima Daiichi Nuclear Complex proceeds, we see a continuation of the same trend. Minute radioactive particles in steam and smoke rose into the atmosphere and were dispersed by wind and rain.  In addition, the proximity of the Fukushima plant to the ocean exacerbated contamination as an immense amount of contaminated ground water leaked into the sea. Although some of the more short-lived radioactive isotopes (such as I-131) soon faded, longer-lasting isotopes continue to cause problems as they travel and coalesce in unexpected areas. The contamination has posed such a problem in ecosystems near the plant that TEPCO began pouring concrete over 786,000 sq. ft. of seafloor near the accident site to encase radioactive materials1.

A recent study published in the journal Proceedings of the National Academy of Science shows another example of traveling radiation. Pacific bluefin tuna were discovered to have carried radiation from the Japanese coast to the shores of Monterrey, California in their annual migrations2. This news is surprising because scientists expected radioactive material to be metabolized and shed by the fish much earlier in their vast migratory movements. The isotopes found were not at dangerous levels for consumption, but definitely identifiable as cesium-134 does not occur naturally in the Pacific Ocean and cesium-137 only occurs at minimal levels. 
Tuna caught off the coast of California are found to have traces of radiation originating in Japan. source
This discovery illustrates how easily radiation can spread even great distances, and is a signal that constant widespread monitoring needs to be part of the Fukushima contamination solution. As radiation continues to travel and settle, we need detectors capable of notifying the public of these trends. Only with increased detection capabilities and constant monitoring can we truly understand the travel patterns of radiation. 
D-tect Systems is a supplier of advanced radiation and chemical detection equipment sold around the world.

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