首次深入了解在氧化变化期间在土中的调动和封存过程
Jianxu Wang1,2, Sabry M Shaheen2, Ann-Christin Swertz3
1State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550082 Guiyang, P.R. China.
Environmental science & technology
|September 25, 2024
概括
石灰岩土壤中的 (As) 构成漏风险,特别是在减少条件下. 动员是由铁矿物质溶解和As(V) 减少驱动的,而氧化和封存则在氧化条件下限制它.
科学领域:
- 环境科学 环境科学
- 地质化学 地质化学
- 土壤科学 土壤科学
背景情况:
- 卡斯特地形是重要的水源,为全球25%的人口提供饮用水.
- 石灰岩土壤中的 (As) 污染对地下水质量构成重大威胁,原因是通过沉坑和断层透.
- 在不断变化的氧化还原条件下,从石土壤中释放的机制尚不清楚.
研究的目的:
- 为了研究 (As) 调动和封存在污染的石灰岩土壤中的机制.
- 了解氧化还原变化在模拟场条件下A的释放和漏中的作用.
主要方法:
- 为了详细的调查,利用了基于同步光子的光谱分析.
- 模拟生物地球化学条件模仿现场验证的氧化还原条件 (低和高E).
- 分析了As的物种化和与土壤矿物质的关联.
主要成果:
- 在低氧化还原潜力 (Eh ≤-100 mV) 时,观察到高溶解As度 (294 μM),主要由 (~95%).
- 低Eh的动员与铁和酸盐的溶解有关,促进的释放和减少.
- 在高氧化还原潜力 (Eh ≥+100 mV) 时,溶解As度较低 (17.0 μM), (~68%) 主导,可能是由于铁相的氧化和封存.
结论:
- 从铁性和非铁性土壤阶段减少的释放是减少条件下的动员的主要驱动因素.
- 铁相的再结晶会影响在氧化条件下的As封存.
- 了解这些依赖氧化还原机制对于评估岩环境中A泄漏风险至关重要.
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