Fukushima’s Drifting Isotopes Monitored

During the nuclear crisis this year at the Fukushima nuclear power plant in Japan, only small amounts of airborne radioactive material reached Europe, according to a monitoring study (Environ. Sci. Technol., DOI: 10.1021/es2017158). Researchers from universities and government agencies pooled data from some 150 monitoring stations across 25 countries in Europe. They focused on radioactive iodine, ¹³¹I, which is of particular concern for human health because it can disrupt thyroid function and cause thyroid cancer. Background ¹³¹I levels in Europe are usually negligible, and they peaked at 4 millibecquerel per m³ during the crisis. All measured ¹³¹I levels were 0.01% to 0.1% of the concentrations detected in Europe after the 1986 Chernobyl accident in Ukraine, says Lars-Erik De Geer of the Swedish Defense Research Agency, who was a coauthor of the study. Because the amount of radioactive material released from Chernobyl didn’t lead to significant health effects in the rest of Europe, the researchers believe the Fukushima radioisotope levels pose no health risk. In a separate report, U.S. researchers estimate that only 0.7% of the radioactive sulfate (³⁵SO₄^2-) generated at Fukushima reached the California coast (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.1109449108).