Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment [April 15, 2011] [open pdf - 466KB]
"The massive Tohoku earthquake and tsunami of March 11, 2011, caused extensive damage in northeastern Japan, including damage to the Fukushima Daiichi nuclear power installation, which resulted in the release of radiation. Some have called this incident the biggest manmade release ever of radioactive material into the oceans. Concerns have arisen about the potential effects of this released radiation on the U.S. marine environment and resources. Both ocean currents and atmospheric winds have the potential to transport radiation over and into marine waters under U.S. jurisdiction. It is unknown whether marine organisms that migrate through or near Japanese waters to locations where they might subsequently be harvested by U.S. fishermen (possibly some tuna in the western Pacific and, less likely, salmon in the North Pacific) might be exposed to radiation in or near Japanese waters, or might consume prey that have accumulated radioactive contaminants. High levels of radioactive iodine-131 (with a half-life of about 8 days), cesium-137 (with a halflife of about 30 years), and cesium-134 (with a half-life of about 2 years) have been measured in seawater adjacent to the Fukushima Daiichi site. EPA rainfall monitors in California, Idaho, and Minnesota have detected trace amounts of radioactive iodine, cesium, and tellurium consistent with the Japanese nuclear incident, with current concentrations below any level of concern. It is uncertain how precipitation of radioactive elements from the atmosphere may affect radiation levels in the marine environment. Scientists have stated that radiation in the ocean will very quickly become diluted and should not be a problem beyond the coast of Japan. The same is true of radiation carried by winds. Barring a major unanticipated release, radioactive contaminants from Fukushima Daiichi should become sufficiently dispersed over time that they will not prove to be a serious health threat elsewhere, unless they bioaccumulate in migratory fish or find their way directly to another part of the world through food or other commercial products."
CRS Report for Congress, R41751
U.S. Department of State, Foreign Press Centers: http://fpc.state.gov/