The Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
The Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2020 Jul 1;724:138246. doi: 10.1016/j.scitotenv.2020.138246. Epub 2020 Mar 26.
The re-emergence of vanadium (V) as a toxic metal has been highlighted recently due to its long-standing environmental and health hazard. This work targeted the world largest reservoir-Three Gorges Reservoir (TGR) to explore the spatial variation of V in the flooding soils from 2014 to 2018; meanwhile, the typical riparian zones with different altitudes and land-uses at the middle reach of the TGR were selected to decipher the key drivers on the V distribution. The results showed that the concentrations of soil V in the mainstream markedly exceeded local background, but they did not vary significantly with time except a marked increase at the upper-middle reaches. Spatially, the concentrations of soil V increased towards the dam, and the increase trend became increasingly significant with time. At the typical riparian zone, the concentrations of soil V decreased strikingly with altitude despite the difference in the land-uses, and a marked change-point occurred at 160-165 m. The soil V dominated by residual fraction, followed by oxidizable and reducible fractions, and then the minimal acid-soluble fraction. The contamination and eco-risk of V in the soils were low with similar spatiotemporal variation to its concentrations. Entrained-sediment flow and particle size rather than pH and organic matters led to the spatiotemporal variation in the distribution of soil V in the mainstream, and the driving effects tended to be more predominant with time. Altitude-regulated alteration of soil properties including particle sizes and iron/manganese (hydr)oxides with different flooding duration dominated the vertical distribution of V over the local land-uses at the riparian zone. Our results reveal the hotspots of V contamination in the riparian soils of the TGR and highlight unceasing focus on the variation in the distribution and dynamic migration of soil V due to its levels out of limits and changing soil conditions.
钒（V）作为一种有毒金属，由于其长期的环境和健康危害，最近再次受到关注。本研究针对世界上最大的水库——三峡水库（TGR），从 2014 年到 2018 年，探讨了洪水土壤中 V 的空间变化；同时，选择了 TGR 中游不同海拔和土地利用类型的典型河岸带，以解析 V 分布的关键驱动因素。结果表明，主流土壤中 V 的浓度明显高于当地背景值，但除了中上游地区明显增加外，它们随时间变化不显著。空间上，土壤 V 的浓度随大坝而增加，随时间的推移，增加趋势越来越显著。在典型的河岸带，尽管土地利用方式不同，土壤 V 的浓度随海拔显著降低，并且在 160-165m 处出现明显的变化点。土壤 V 主要以残渣态为主，其次是可氧化态和可还原态，然后是最小的酸可溶态。土壤 V 的污染和生态风险较低，其浓度的时空变化相似。与 pH 值和有机物相比，挟沙水流和粒径导致了主流中土壤 V 分布的时空变化，并且随着时间的推移，驱动作用往往更加显著。海拔调节的土壤性质变化，包括粒径和铁/锰（氢）氧化物，随着不同的洪水持续时间，主导了河岸带局部土地利用类型的 V 的垂直分布。我们的研究结果揭示了 TGR 河岸带土壤中 V 污染的热点，并强调了由于 V 含量超出限值和土壤条件变化，不断关注土壤 V 分布和动态迁移的变化。
