title: Colloid-associated plutonium transport in the vadose zone sediments at Lop Nor.
abstract: A framework to describe the characteristics of pore water in unsaturated media was established in order to study transport of colloid-associated (239)Pu (i.e., colloidal Pu) through the vadose sediments. Effluent concentrations and recoveries of Pu were found to decrease with increasing ionic strength. However, they would remain approximately constant at a critical value of 0.0289 M (Na(+)) though ionic strengths were further increased. Fast deposition rate coefficient (k(fast)) was thus experimentally determined. To our knowledge, this relationship between the mobility of colloidal Pu and the critical ionic strength was the first time observed. On the other hand, significant detachment of colloidal Pu once retained in the sediments was not observed during the subsequent chemical and physical perturbations. But slow release and transport could persist as long as flow continued. The threshold infiltration intensity (0.166 cm/min) revealed a nonmonotonic dependence of the cumulative amount of detached colloidal Pu on the intensity.
authors.affiliation: Northwest Institute of Nuclear Technology, P.O. Box 69-14, Xi'an City, Shanxi Province 710024, PR China. xiejinchuan@hotmail.com
authors.forename: Jinchuan
authors.initials: J
authors.lastname: Xie
authors.forename: Xuihui
authors.initials: X
authors.lastname: Wang
authors.forename: Jiachun
authors.initials: J
authors.lastname: Lu
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Zhou
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Lin
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.forename: Qichu
authors.initials: Q
authors.lastname: Xu
authors.forename: Lili
authors.initials: L
authors.lastname: Du
authors.forename: Yueheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Guoqing
authors.initials: G
authors.lastname: Zhou
mesh_terms: D002681:China; D003102:Colloids; D019015:Geologic Sediments / Q000032:analysis*; D060587:Groundwater / Q000032:analysis; D009994:Osmolar Concentration; D011005:Plutonium / Q000032:analysis*; D011834:Radiation Monitoring; D014872:Water Movements; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D003102:Colloids; D014875:Water Pollutants, Radioactive; D011005:Plutonium