Minor Fallout from Daiichi Plant Reached US
A study released by the U.S. Geological Survey confirms EPA measurements soon after the March 2011 earthquake and tsunami damaged the nuclear plant.
Fallout reaching U.S. soil via rainfall as a result of the damaged Fukushima Daiichi plant was minimal, the U.S. Geological Survey reported Feb. 22 in findings that confirmed EPA measurements shortly after the March 2011 release of radioactive elements from it. The damage resulted from an offshore earthquake that produced a devastating tsunami and crippled the plant's cooling systems.
Extensive damage to the plant is still visible, and operators of nuclear power plants in Japan that could be vulnerable to similar natural disasters have been slow to install coastal levees to mitigate tsunamis or measures to prevent hydrogen explosions, Jin Nishikawa and Takashi Sugimoto reported Feb. 22 for The Asahi Shimbun. According to USGS, the new study sampled 167 U.S. sites using the National Atmospheric Deposition Program (NADP) network and found radioactivity levels at about 20 percent of them that were similar to EPA's measurements, which were "well below any level of public health concern," according to USGS.
"Japan's unfortunate nuclear nightmare provides a rare opportunity for U.S. scientists to test an infrequently needed national capability for detecting and monitoring nuclear fallout over a wide network," said USGS Director Marcia McNutt. "Had this been a national incident, NADP would have revealed the spatial and temporal patterns of radioactive contamination in order to help protect people and the environment."
USGS scientists detected Iodine -131, Cesium-134, and Cesium-137 most frequently along the West Coast, in the central and northern Rocky Mountain states, and in the eastern United States where precipitation fell most heavily in the weeks after the Fukushima disaster. EPA had used the rapid-response RadNet to monitor network fallout from Fukushima immediately afterward. (RadNet sites provide information about levels of radiation in the nation's air, drinking water, precipitation, and pasteurized milk.)
Samples from the NADP network have been used only once before to measure radioactive fallout: after the Chernobyl disaster in 1986.