Institute of Geography, University of Bern, Switzerland.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, PR China.
Sci Total Environ. 2022 Oct 10;842:156631. doi: 10.1016/j.scitotenv.2022.156631. Epub 2022 Jun 9.
The fate of antimony (Sb) in submerged soils and the impact of common agricultural practices (e.g., manuring) on Sb release and volatilization is understudied. We investigated porewater Sb release and volatilization in the field and laboratory for three rice paddy soils. In the field study, the porewater Sb concentration (up to 107.1 μg L) was associated with iron (Fe) at two sites, and with pH, Fe, manganese (Mn), and sulfate (SO) at one site. The surface water Sb concentrations (up to 495.3 ± 113.7 μg L) were up to 99 times higher than the regulatory values indicating a potential risk to aquaculture and rice agriculture. For the first time, volatile Sb was detected in rice paddy fields using a validated quantitative method (18.1 ± 5.2 to 217.9 ± 160.7 mg ha y). We also investigated the influence of two common rice agriculture practices (flooding and manuring) on Sb release and volatilization in a 56-day microcosm experiment using the same soils from the field campaign. Flooding induced an immediate, but temporary, Sb release into the porewater that declined with SO, indicating that SO reduction may reduce porewater Sb concentrations. A secondary Sb release, corresponding to Fe reduction in the porewater, was observed in some of the microcosms. Our results suggest flooding-induced Sb release into rice paddy porewaters is temporary but relevant. Manuring the soils did not impact the porewater Sb concentration but did enhance Sb volatilization. Volatile Sb (159.6 ± 108.4 to 2237.5 ± 679.7 ng kg y) was detected in most of the treatments and was correlated with the surface water Sb concentration. Our study indicates that Sb volatilization could be occurring at the soil-water interface or directly in the surface water and highlights that future works should investigate this potentially relevant mechanism.
锑（Sb）在潜水土壤中的命运以及常见农业措施（例如施肥）对 Sb 释放和挥发的影响研究较少。我们研究了三种稻田土壤的现场和实验室中的孔隙水 Sb 释放和挥发。在现场研究中，两个地点的孔隙水 Sb 浓度（高达 107.1μg/L）与铁（Fe）有关，一个地点的孔隙水 Sb 浓度与 pH、Fe、锰（Mn）和硫酸盐（SO）有关。地表水 Sb 浓度（高达 495.3±113.7μg/L）比监管值高 99 倍，表明对水产养殖和水稻农业有潜在风险。首次使用经过验证的定量方法在稻田中检测到挥发性 Sb（18.1±5.2 至 217.9±160.7mg/ha/y）。我们还使用来自野外调查的相同土壤在 56 天的微宇宙实验中研究了两种常见的水稻农业措施（淹水和施肥）对 Sb 释放和挥发的影响。淹水会立即但暂时将 Sb 释放到孔隙水中，随着 SO 的减少，孔隙水中的 Sb 浓度会降低，这表明 SO 的减少可能会降低孔隙水中的 Sb 浓度。在一些微宇宙中观察到与孔隙水中 Fe 还原相对应的二次 Sb 释放。我们的结果表明，淹水引起的 Sb 释放到稻田孔隙水中是暂时的，但相关的。施肥不会影响孔隙水 Sb 浓度，但会增强 Sb 的挥发。在大多数处理中都检测到挥发性 Sb（159.6±108.4 至 2237.5±679.7ng/kg/y），并与地表水 Sb 浓度相关。我们的研究表明，Sb 挥发可能正在土壤-水界面或直接在地表水发生，并强调未来的工作应调查这一潜在相关机制。
