Low levels of radiation from Fukushima persist in seafood

Japanese eel

Researchers have found that large freshwater species like wild Japanese eel may carry higher levels of lingering radioactive cesium from the Fukushima nuclear disaster. Most freshwater fish eaten in Japan come from cultures, not wild catches, but the findings have implications for recreational fishing. 

opencage/Wikimedia Commons (CC BY-SA 2.5)

Radiation from the 2011 disaster at the Fukushima Daiichi nuclear power plant contaminates most Japanese seafood at low levels, researchers estimate February 29 in the Proceedings of the National Academy of Sciences.

For aquatic foods, data on lingering concentrations of cesium is limited in terms of the number of species sampled and the levels that surveys can even detect. To fill in the blanks, a team of researchers in Japan drew from survey measurements from April 2011 to September 2015 and devised a way to predict cesium contamination in different aquatic species across Japan.

The analysis provides mixed news: Overall, cesium contamination is pretty low. But, some species retain higher levels than others. Larger fish near the top of the food web tended to have the highest levels of contamination. The researchers predict that such factors put some wild freshwater species like the whitespotted char (Salvelinus leucomaenis leucomaenis) and the Japanese eel (Anguilla japonica) at higher risk for contamination. 

Helen Thompson is the multimedia editor. She has undergraduate degrees in biology and English from Trinity University and a master’s degree in science writing from Johns Hopkins University.

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