College of Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
J Hazard Mater. 2010 May 15;177(1-3):620-5. doi: 10.1016/j.jhazmat.2009.12.077. Epub 2009 Dec 24.
Shooting range soils with elevated Pb contents are of environmental concern due to their adverse impacts on human and animals. In Florida, the problem merits special attention because of Florida's sandy soil, high rainfall, and shallow groundwater level, which tend to favor Pb migration. This study used large intact soil column to examine colloid-facilitated Pb transport in two Florida shooting-range soils with different physicochemical properties (e.g., organic carbon content, pH, and clay content). Simulated rainwater (SRW) was pumped through the intact soil columns under different ionic strengths (0.07 and 5 mmol L(-1)) and flow rates (2.67, 5.30 and 10.6 cm h(-1)) to mobilize Pb and soil colloids. Our results showed that colloids dominated Pb transport in both soils and there was a significant correlation between colloids and Pb in the leachates. Decreases in ionic strength and increases in flow rate enhanced the release of both colloids and Pb in the soils. Size fraction analyses showed that in OCR soils (sandy soils with low organic carbon), most of the Pb (87%) was associated with coarse colloid fraction (0.45-8 microm). However, high Pb level (66%) was found in the dissolved and nano-sized colloid fraction (<0.1 microm) in the MPR soils (sandy soils with high organic carbon). This suggests that soil properties are important to Pb migration in soils and groundwater. Our study indicated that colloids play an important role in facilitating Pb transport in shooting range soils.
由于其对人类和动物的不良影响，含铅量高的射击场土壤引起了环境方面的关注。在佛罗里达州，由于该州的土壤多沙、降雨量高且地下水位浅，这些因素都有利于铅的迁移，因此该问题值得特别关注。本研究使用大型完整土柱，研究了两种具有不同理化性质（例如，有机碳含量、pH 值和粘粒含量）的佛罗里达州射击场土壤中胶体促进的铅迁移。模拟雨水（SRW）在不同离子强度（0.07 和 5 mmol/L）和流速（2.67、5.30 和 10.6 cm/h）下被泵入完整土柱中，以动员铅和土壤胶体。结果表明，胶体主导了两种土壤中的铅迁移，并且浸出液中的胶体和铅之间存在显著相关性。离子强度降低和流速增加均增强了土壤中胶体和铅的释放。粒径分析表明，在 OCR 土壤（含碳量低的沙质土壤）中，大部分铅（87%）与粗胶体（0.45-8 μm）有关。然而，在 MPR 土壤（含碳量高的沙质土壤）中，溶解态和纳米级胶体（<0.1 μm）中的铅含量很高（66%）。这表明土壤性质对土壤和地下水中的铅迁移很重要。本研究表明，胶体在促进射击场土壤中的铅迁移方面发挥了重要作用。
