title: Association of Plutonium isotopes with natural soil particles of different size and comparison with137Cs.
abstract: Information on how plutonium (Pu) isotopes associate with natural soil particles of different size is very important for the interpretation involved in the application of Pu isotopes as soil erosion tracers. This work investigated the association of Pu isotopes with different particle size fractions of natural soils and compared it with that of137Cs. Ten bulk soils collected from two different areas were separated into different particle size fractions by a combination of wet sieving and centrifugation techniques and the sub-samples were analyzed for137Cs,239Pu and240Pu. Results showed that the concentrations of both239+240Pu and137Cs increase with decreased particle sizes and are closely related to the specific surface areas of soil particles, which demonstrated a similar preferential association of Pu with finer soil particles as137Cs. The activity ratios of239+240Pu/137Cs in soil fractions increasing with increased particle size further indicated a less preferential transport of Pu with fine particles compared to137Cs. These results not only highlight the suitability of Pu isotopes as soil erosion tracers, but also provide useful information for assessing the migration behavior of Pu in contaminated environments.
authors.affiliation: The key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China. Electronic address: yhxu@nju.edu.cn.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: The key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China. Electronic address: span@nju.edu.cn.
authors.forename: Shaoming
authors.initials: S
authors.lastname: Pan
authors.affiliation: The key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Wu
authors.affiliation: The key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
authors.forename: Kexin
authors.initials: K
authors.lastname: Zhang
authors.affiliation: The key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
authors.forename: Yongpei
authors.initials: Y
authors.lastname: Hao
keywords: (239+240)Pu/(137)Cs activity ratio; Pu isotopes; Size distribution; Soil particles; Wet-sieving