The word from the land is bad enough. As my colleague Hiroko Tabuchi reported on Saturday, Japanese officials have detected elevated radiation levels in rice near the crippled reactors. Worrying radiation levels had already been detected in beef, milk, spinach and tea leaves, leading to recalls and bans on shipments.
Off the coast, the early results indicate that very large amounts of radioactive materials were released, and may still be leaking, and that rather than being spread through the whole ocean, currents are keeping a lot of the material concentrated.
Most of that contamination came from attempts to cool the reactors and spent fuel pools, which flushed material from the plant into the ocean, and from direct leaks from the damaged facilities.
Japanese government and utility industry scientists estimated this month that 3,500 terabecquerels of cesium 137 was released directly into the sea from March 11, the date of the earthquake and tsunami, to late May. Another 10,000 terabecquerels of cesium 137 made it into the ocean after escaping from the plant as steam.
Chernobyl-induced radiation in the Black Sea peaked in 1986 at about 1,000 becquerels per cubic meter, he said in an interview at his office in Woods Hole, Mass. By contrast, the radiation level off the coast near the Fukushima Daiichi plant peaked at more than 100,000 becquerels per cubic meter in early April.
While Mr. Buesseler declined to provide details of the findings before analysis is complete and published, he said the broad results were sobering.
“When we saw the numbers — hundreds of millions of becquerels — we knew this was the largest delivery of radiation into the ocean ever seen,’’ he said. ‘‘We still don’t know how much was released.’’
Mr. Buesseler took samples of about five gallons, filtered out the naturally occurring materials and the materials from nuclear weapon explosions, and measured what was left.
The study also found that the highest cesium values were not necessarily from the samples collected closest to Fukushima, he said, because eddies in the ocean currents keep the material from being diluted in some spots farther offshore.
- Radiation spread reaches Chiba, Saitama prefectures – Up to 60,000 bq/m3 over 200 km from Fukushima Daiichi (enformable.com)
- Japanese Rice’s Radiation Levels Stump Scientists – Fukushima tests show rice contamination over thought transfer coefficient (enformable.com)
- Fukushima Still Spiraling Out of Control – Air and Ocean Contamination Likely to Continue While Groundwater Contamination Is Concerning to Experts (enformable.com)
- 34 points near Fukushima plant exceed radiation standard used for Chernobyl (enformable.com)