Nuclear Tuna Coming to Town

Remember Fukushima nuclear disaster in 2011?

It was the most serious disaster since the Chernobyl disaster in 1986. The crippled reactors released an estimated 22 x 10E 15 Becquerel of Cesium-137 into the ocean, which was then picked up by the Pacific bluefin tuna, Thunnus orientalis and carried all the way across the northern Pacific.

And they got caught by fishermen from Mexico and Southern California.

Image: mnn.com

The bluefin tuna is a migratory fish. Mature fish spawn in the western Pacific, and young fish migrate eastward to the California Current Large Marine Ecosystem (CCLME) when they are 1~2 years old. Some scientists from Stanfod and Stony Brook University bought 15 2-year-old fish caught off San Diego last year to test for the presence of Fukushima-derived radionuclides.

And sure enough, they did find traces of Cesium-134 and Cesium-137 in all 15 fish, and the level was ten times higher than those caught in previous years.

Image: article.wn.com

The scientists, however, said they weren't worried about the radiation level. The Cesium levels in the "contaminated" tunas were thirty times less than concentrations of natural-occuring Potassium-40, and 200 times less than the natural-occuring Polonium-210. Moreover, seafood in general contains traces of Cesium-137 leftover from nuclear weapon testing in the 1950s and 1960s.

In addition, tuna also carries other contaminants which are far more potent than Cesium. One example is methyl mercury, a neurotoxin that could harm developing fetuses.

So if you seek to kill yourself by eating radionuclide-contaminated sushi, you would have to, according to Robert Emery at the University of Texas Health Science Centre, gorge down 2.5 to 4 tons of tuna to acquire the amount of Cesium that exceeds health limit.

Image: newscandy.com

Good luck.

Malcolm
info: 
Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California.Daniel J. Madigana, Zofia Baumannb, and Nicholas S. Fisherb. PNAS June 12, 2012 vol. 109 no. 24. doi: 10.1073/pnas.1204859109