Variation of atmospheric 137Cs and possible carriers in aerosol samples obtained in Namie in a heavily contaminated area of Fukushima prefecture in 2019
Abstract. A lot of radionuclides were released into the environment from Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on March 11, 2011. Because of the long half-life (30.12 years) and high-concentration deposition about 137Cs, the study regarding on the distribution of 137Cs in aerosol samples and the understanding carriers of 137Cs became a hot topic in the recent decade. However, even nine years after FDNPP accident, the explanation for the fluctuations of 137Cs and their carriers in the atmosphere remains elusive. In this study, a small fluctuation within 0.0002 Bqm-3 from January to April and a slightly higher level of atmospheric 137Cs from May to September was still observed in the aerosol samples obtained in Namie in a heavily contaminated area of Fukushima prefecture in 2019. Therefore, new observations, obtaining by fluorescent upright microscope and scanning electron microscopes (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), quantitatively demonstrated that the carriers of 137Cs were the combination of C-particles and Al-particles (Al-particles was dominated with the percentage of 68 %) in early May; meanwhile the predominate carriers of 137Cs were carbonaceous particles with the average percentage of 88 % in late May and September. Significantly, small particles (less than 2 μm) and medium particles (2–8 μm) of carbonaceous particles had a higher level in the aerosol samples of May and September. Specially, little particles (less than 1 μm), bacteria (1–1.8 μm), and spores (1.8–10 μm) had a linear relationship with the distribution of atmospheric 137Cs in the aerosol samples of September. In addition, the temperature and the precipitation were the main impact factors on the distribution of 137Cs and its carriers.
Status: open (until 07 Mar 2024)
Viewed (geographical distribution)