Seasonal and spatial variation of atmospheric 210Pb and 7Be deposition: features of the Japan Sea side of Japan

High 210Po atmospheric deposition flux in the subtropical coastal area of Japan

“…Similarly, the 210 Pb atmospheric deposition at Akajima in the lower latitude zone (26 N) (78.5 AE 8.0 Bq m À2 y À1 ) was 0.40 times that observed at the Tsuyazaki coastal area (33 N). All of our results for Japanese temperate and subtropical areas were comparable to previously reported 210 Pb fluxes in the 20 e30 N latitude zone in Asia (approximately 100e 200 Bq m À2 y À1 ) (Preiss et al, 1996;Su and Huh, 2003), while lower than annual deposition fluxes reported for higher latitude areas (35 e44 N, 190e700 Bq m À2 y À1 ) in northern Japan (Fukuda and Tsunogai, 1975;Tsunogai et al, 1985;Tokeida et al, 1996;Yamamoto et al, 2006).…”

“…In contrast, for marginal areas of the Pacific Ocean such as the Akajima area where 210 Pb-depleated Pacific oceanic air prevails, local 210 Pb deposition was low. Though Yamamoto et al (2006) did not report lower 210 Pb deposition for the Okinawa area compared to the Japanese mainland, our results for 210 Pb deposition flux in the lower latitude zone (around 26 N) showed that the atmospheric 210 Pb deposition is reduced in the 25 N zone in ocean air-mass affected areas such as Okinawa. In contrast to the 210 Pb, the estimated 210 Po fluxes at the three study sites (Table 4) show that the annual 210 Po deposition flux at Akajmia (58.4 AE 7.7 Bq m À2 y À1 ) was 2.7e4.5 times larger than those at Tsuyazaki (21.9 AE 4.4 Bq m À2 y À1 ) and Odawa Bay (13.0 AE 2.3 Bq m À2 y À1 ).…”

Speciation of 210Po and 210Pb in air particulates determined by sequential extraction

“…Only total suspended particulates were collected and analysed in this study; no particle size distribution was determined. Several other studies (Marley et al, 2000;Paadero et al, 2003;Vecchi et al, 2005;Yamamoto et al, 2006;Narayana et al, 2006;Gaffney et al, 2004) focused on this topic. Higher values of both radionuclides were observed in the mine site than the Tartous port site and a high radon and phosphate dust concentration was expected.…”

“…These also depend on the climatic conditions during the release, which are variable throughout the year. The dominant radioactive isotopes in fine aerosols are 210 Pb and its daughters 210 Bi and 210 Po (Marley et al, 2000;Paadero et al, 2003;Vecchi et al, 2005;Yamamoto et al, 2006;Narayana et al, 2006). Another recent study (Gaffney et al, 2004) showed that most 210 Pb is in the submicron aerosol component and significant concentrations of this radionuclide were found in the size range higher than 1 mm.…”

Evaluation of historical beryllium abundance in soils, airborne particulates and facilities at Lawrence Livermore National Laboratory

“…Be-7 attaches predominantly to aerosols in the submicron size range, and is susceptible to the same transport and depositional processes governing these aerosols, making it a useful tracer of atmospheric particulate matter (Doering and Akber, 2008). Several studies have shown that atmospheric Be-7 concentrations are seasonally variable, with a maximum in the summer season and a minimum in the fall/winter months (Azahra et al, 2004;Doering and Akber, 2008;Yamamoto et al, 2006). Feely et al (1989) investigated the atmospheric Be-7 concentration at a large number of sites across the world.…”