Depositional behaviors of plutonium and thorium isotopes at Tsukuba and Mt. Haruna in Japan indicate the sources of atmospheric dust

作者：Hirose K^*; Igarashi Y; Aoyama M; Inomata Y

来源：Journal of Environmental Radioactivity, 2010, 101(2): 106-112.

DOI：10.1016/j.jenvrad.2009.09.003

• Soil contaminants
• Plutonium
• Thorium isotopes
• Deposition
• Re-suspension
• Dust
• Massic activity

Monthly plutonium and thorium depositions at Tsukuba (28 m asl) and Mt. Haruna (1370 In asl) were measured during 2006 and 2007 (Jan 2006-Dec 2007 at Tsukuba, Nov 2006-Dec 2007 at Mt. Haruna). The monthly (239,240)Pu depositions ranged from 0.044 to 2.67 mBq m(-2) at Tsukuba and from 0.05 to 0.9 mBq m(-2) at Mt. Haruna during the measurement periods. Monthly (239,240)Pu deposition did not differ markedly between the two sites except in April 2007. Seasonal pattern of monthly (239,240)Pu depositions at both sites showed high in spring and low in summer, and typical of seasonal variations in northeastern Asia. Thorium deposition at Tsukuba was higher than that at Mt. Haruna except in May and June 2007. (239,240)Pu activity ratios were used to partition deposition samples into locally and remotely derived fractions. The results revealed that a major proportion of total (239,240)Pu and Th deposits are derived from remote sources, especially in spring.

• 出版日期2010-2
• 单位中国气象科学研究院