title: Plutonium as a tracer for soil erosion assessment in northeast China.
abstract: Soil erosion is one of the most serious environmental and agricultural problems faced by human society. Assessing intensity is an important issue for controlling soil erosion and improving eco-environmental quality. The suitability of the application of plutonium (Pu) as a tracer for soil erosion assessment in northeast China was investigated by comparing with that of 137Cs. Here we build on preliminary work, in which we investigated the potential of Pu as a soil erosion tracer by sampling additional reference sites and potential erosive sites, along the Liaodong Bay region in northeast China, for Pu isotopes and 137Cs. 240Pu/239Pu atomic ratios in all samples were approximately 0.18, which indicated that the dominant source of Pu was the global fallout. Pu showed very similar distribution patterns to those of 137Cs at both uncultivated and cultivated sites. 239+240Pu concentrations in all uncultivated soil cores followed an exponential decline with soil depth, whereas at cultivated sites, Pu was homogenously distributed in plow horizons. Factors such as planted crop types, as well as methods and frequencies of irrigation and tillage were suggested to influence the distribution of radionuclides in cultivated land. The baseline inventories of 239+240Pu and 137Cs were 88.4 and 1688 Bq m(-2) respectively. Soil erosion rates estimated by 239+240Pu tracing method were consistent with those obtained by the 137Cs method, confirming that Pu is an effective tracer with a similar tracing behavior to that of 137Cs for soil erosion assessment.
authors.affiliation: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Center for Nuclear Technologies, Technical University of Denmark, Risø Campus, DK-4000 Roskilde, Denmark.
authors.forename: Jixin
authors.initials: J
authors.lastname: Qiao
authors.affiliation: 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: Center for Nuclear Technologies, Technical University of Denmark, Risø Campus, DK-4000 Roskilde, Denmark; Xi'an AMS Center, SKLLQG, Institute of Earth Environment, CAS, Xi'an 710075, China. Electronic address: xiho@dtu.dk.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Hou
authors.affiliation: Center for Nuclear Technologies, Technical University of Denmark, Risø Campus, DK-4000 Roskilde, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Roos
authors.affiliation: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
authors.forename: Liguo
authors.initials: L
authors.lastname: Cao
keywords: (137)Cs; Cultivated land; Northeast China; Pu isotopes; Soil erosion models; Tracing technique