Resuspension processes controll variations of 137Cs activity concentrations in the ground-level air

The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan

“…Similar seasonal variations at all sites indicate that resuspension occurred with identical processes/sources in both open areas and forests. This result is opposite to that of the seasonal variation (high in winter and low in summer) found in urban areas by other studies (e.g., Igarashi et al 2015;Sýkora et al 2012;Watanabe 2014), suggesting that the dominant resuspension processes/ sources are different because of the locations/surface conditions of the study areas, specifically between the urban sites and the forest sites. The sampling sites in our study are located in low mountainous areas, where the major land uses are agricultural fields (abandoned because of the evacuation) placed along valleys and forests covering mountain slopes.…”

“…These mineral particles were shown to act as resuspended host particles in an atmospheric environment by the previous investigations of the global fallout from atmospheric nuclear weapon tests (e.g., Igarashi et al 2005;Masson et al 2010). Therefore, a major resuspension source has been thought to be the suspension of contaminated dust particles by wind Ishizuka et al 2017;Sýkora et al 2012), even for the case of the FDNPP accident contamination. In addition, a significant amount of water-soluble cesium ions has been absorbed by living organisms, such as mushrooms (Yoshida et al 1994) and plants, and has been relocated within vegetation, from bacteria (Tomioka et al 1992), through plant roots (Ehlken and Kirchner 2002), to pollen and then to honey (Barišić et al 1992;Kanasashi et al 2015).…”

“…The highest total radiocesium concentration in Fukushima cedar pollen was reported to be 25.4 Bq g − 1 (dry weight) in 2014 (Forestry Agency, Japan (FAJ) 2015), suggesting that pollen emissions could still be a candidate for the host particles of radiocesium resuspensions, although pollen emissions occur during limited durations of weeks or months each year depending on plant species. Furthermore, open biomass burning of contaminated vegetation is also a candidate for the radiocesium resuspension process (Bourcier et al 2010;Igarashi 2009;Lujanienė et al 2009;Sýkora et al 2012;Yoschenko et al 2006). Many studies have been carried out to address the environmental radiocesium contamination resulting from the FDNPP accident, but the processes of radiocesium resuspension have not yet been fully identified in this case.…”

Long-term variations of radionuclides in the Bratislava air

“…They have been dispersed all over the world and deposited back to the ground by gravitational settling and precipitation washout. The 137 Cs is presently found mainly in soils and vegetation, and it can get back into the atmosphere by soil resuspension (Pham et al, 2011;Povinec et al, 2012a;Sýkora et al, 2012) and by biomass burning (Bourcier et al, 2010;Hirose and Povinec, 2015). Seasonal variations of the 137 Cs concentration in the atmosphere, associated with local meteorological conditions (like winds, air temperature, pressure and precipitations) were observed in post-Chernobyl period by several authors (Rosner et al, 1996;Lee et al, 2002;Pham et al, 2011;Bourcier et al, 2011;Povinec et al, 2012a).…”

“…They get into the air from surface soil predominantly during spring and autumn when field agricultural activities are frequent, and strong winds transport these radionuclides not only locally but also regionally. Their variations in ground-level air have usually been correlated with other aerosol radionuclides of different origin ( 7 Be, 210 Pb,137 Cs), and used as tracers for investigation of surface soil erosion and intrusion of dust particles into the atmosphere (H€ otzl and Winkler, 1987;Sýkora et al, 2012;Blazej and Mietelski, 2014). A specific case is transport of Saharan sand from North Africa to South Europe (Pham et al, 2005(Pham et al, , 2016Hirose and Povinec, 2015), as well as from Asian deserts in China and Mongolia to East Asia (Korea and Japan) (e.g., Igarashi et al, 2005).…”