April 03, 2012
CRS: Effects of Radiation from Fukushima Dai-ichi on the U.S. Marine Environment
"The massive Tohoku earthquake and tsunami of March 11, 2011, caused extensive damage in northeastern Japan, including damage to the Fukushima Dai-ichi 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 arose 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 albacore tuna or salmon in the North Pacific) might have been exposed to radiation in or near Japanese waters, or might have consumed prey with 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) were measured in seawater adjacent to the Fukushima Dai-ichi site after the March 2011 events. EPA rainfall monitors in California, Idaho, and Minnesota detected trace amounts of radioactive iodine, cesium, and tellurium consistent with the Japanese nuclear incident, at concentrations below any level of concern. It is uncertain how precipitation of radioactive elements from the atmosphere may have affected radiation levels in the marine environment...Based on computer modeling of ocean currents, debris from the tsunami produced by the Tohoku earthquake was projected to spread eastward from Japan in the North Pacific Subtropical Gyre. Approximately two to three years after the event, the debris plume likely will reach the U.S. West Coast, dumping debris on California beaches and the beaches of British Columbia, Alaska, and Baja California. Although much of the radioactive release from Fukushima Dai-ichi is believed to have occurred after the tsunami, there is the possibility that some of the tsunami debris might also be contaminated with radiation."