The detection of Fukushima-derived radiocesium in the Bering Sea and Arctic Ocean six years after the nuclear accident

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, radionuclides released by this event were observed in the Pacific Ocean. Models predicted that these radionuclides would be transported to the Bering Sea; however, limited evidence currently reveals the transportation of these radionuclides to the Arctic Ocean. Here, we provide the first direct observation showing that FDNPP-derived 134Cs and 137Cs were present in subarctic regions and the Arctic Ocean (Chukchi Sea) in 2017. Furthermore, we conclude that these radionuclides were transported from the Pacific Ocean into the Bering and Chukchi Seas by ocean currents. Additionally, the 137Cs activity concentrations in the Bering Sea exceed those in all previous reports. Due to the continuous leaking of radionuclides from the FDNPP, we hypothesize that FDNPP-derived radionuclides will be continuously transported to the Arctic Ocean in the next several years. Our results suggest that though far away from Fukushima, the accident-derived anthropogenic radionuclides also influenced the Arctic Ocean by ocean currents. [Display omitted] •134Cs was observed in the Bering and Chukchi Seas in 2017.•Fukushima-derived radiocesium from the Pacific Ocean was transported into the Bering and Chukchi Seas by ocean currents.•Fukushima-derived radiocesium may be transported separately into the Bering Basin and Bering Strait from the Bering Shelf. An analysis of radiocesium in seawater samples six years after the Fukushima accident indicated that accident-derived radiocesium has been transported into the Arctic Ocean by ocean currents.