title: [Effects of aging time on the form transformation and eco-toxicity threshold (ECx) of added Zn in typical China soils].
abstract: Six typical China soils with different properties were selected and added with seven concentrations of ZnCl2 to study the effects of different aging time (14, 90, 180, 360, and 540 days) on the form transformation and eco-toxicity threshold (ECx) of added Zn in the soils, with the main affecting factors analyzed. The results indicated that with the increase of aging time, the fraction of 0.01 mol x L(-1) CaCl2-extracted Zn in the soils decreased sharply initially, then slowed down, and reached the dynamic balance after 540 d incubation. The eco-toxicity thresholds (ECx, x = 10, 50) of Zn to bok choy increased significantly with aging time (P < 0.05), which implied the marked decrease of the phyto-toxicity of Zn. The measured aging factors AF10 and AF50 of Zn ranged from 1.077-1.743 and 1.174-1.441, respectively, and increased with aging time. The balanced concentration of Zn in the soils was significantly negatively correlated with soil pH, CEC, and organic carbon (Org-C) content, and soil pH was the most important controlling factor, followed by CEC and Org-C. It took shorter time to reach Zn balance in the soils with higher pH. The prediction model of the ECx of Zn was developed based on the aging factors and the main soil properties, and could be well validated by the measured ECx under field condition. This study would provide theoretical basis for the normalization of the eco-toxicity thresholds of added Zn in different soils and the formulation of the environmental criterion of Zn in China soils.
authors.affiliation: Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China. linlei8822@163.com
authors.forename: Lei
authors.initials: L
authors.lastname: Lin
authors.forename: Shi-Bao
authors.initials: SB
authors.lastname: Chen
authors.forename: Ji-Fang
authors.initials: JF
authors.lastname: Liu
authors.forename: Yi-Bing
authors.initials: YB
authors.lastname: Ma
mesh_terms: D002681:China; D017753:Ecosystem; D004777:Environment; D004784:Environmental Monitoring; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry; D013997:Time Factors; D015032:Zinc / Q000032:analysis / Q000737:chemistry*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D015032:Zinc