Widespread distribution of radiocesium-bearing microparticles over the greater Kanto Region resulting from the Fukushima nuclear accident

Abstract

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011 emitted a considerable amount of radioactive materials. This study isolated radiocesium-bearing microparticles (CsMPs), a form of radioactive materials emitted from the FDNPP at the early stage of the accident, from aerosols collected hourly on filter tapes at seven monitoring stations at the greater Kanto Region, including the Tokyo metropolitan area, on 15 March 2011. The aerosols had a spherical shape ~ 1 μm in diameter with activity of less than 1 Bq of 137Cs per particle. Their physical and chemical characteristics, including radioactivity ratio 134Cs/137Cs as well as chemical composition and state, are essentially the same as previously reported CsMPs. This study demonstrated that air parcels containing CsMPs emitted from the FDNPP were widespread over the greater Kanto Region, more than 250 km away from the FDNPP, during the daytime of 15 March. Trajectory analysis indicated that these particles were emitted from the reactor No. 2 of FDNPP between 14 March evening and 15 March early morning. The information obtained on the widespread distribution of CsMPs can be useful for assessing the actual impacts of radioactive contamination from the FDNPP accident on the environment and human health.

The Discovery of Radiocesium-bearing Microparticles Directly Delivered to a Person in Tokyo as a Result of the Fukushima Daiichi Nuclear Disaster

“…Another previous study found eight CsMPs in seven suspended particulate matter monitor filters used on 15 March 2011 (Abe et al 2021). The sample was aspirated using a pump with almost the same flow velocity as that of human breath.…”

Improved Radio-Cesium Detection Using Quantitative Real-Time Autoradiography

“…Moreover, CsMPs can be transported (e.g., as dust in the air, by flowing water, etc. ), resulting in an unpredictable, changing radio-Cs distribution in the environment. − Given the existence of CsMPs and their potential long-term impact on the environment and human health, it is essential to detect, evaluate, and differentiate the varying forms of radio-Cs (micro-particle or bulk) found in samples.…”

Atmospheric dispersion of chemical, biological, and radiological hazardous pollutants: Informing risk assessment for public safety

“…Reprinted with permission from ref. [ 227 ] (open access article distributed under the terms of the Creative Commons CC BY license). (b) Identified radioactive plume and reconstructed cloud shine for the in-situ measurements of gamma dose rate obtained at Futatsunuma during the Fukushima accident, between 2:00 UTC, March 14 and 10:00 UTC, March 22, 2011.…”