Characterization of Suboxic Groundwater Colloids Using a Multi-method Approach

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• 作者：Dan J. Lapworth ; Bj枚rn Stolpe ; Peter J. Williams ; Daren C. Gooddy ; Jamie R. Lead
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：March 19, 2013
• 年：2013
• 卷：47
• 期：6
• 页码：2554-2561
• 全文大小：421K
• 年卷期：v.47,no.6(March 19, 2013)
• ISSN：1520-5851

文摘

Anoxic groundwater colloid properties were measured using a minimally perturbing procedure for sampling, processing, and analysis. Analytical methods included atomic force microscopy (AFM), flow field flow fractionation (FlFFF), and transmission and scanning electron microscopy (TEM and SEM). Shallow groundwater samples showed abundant iron rich nanoparticles (NP) with diameters of 10鈥?0 nm as well as a smaller heterogeneous polydisperse dissolved organic matter (DOM) fraction. AFM results showed NP with average heights of 10 卤 2 nm, which was corroborated by high-resolution TEM and SEM. FlFFF with UV254 nm detection found particles with number average diffusion coefficients of 2鈥? 脳 10^鈥?0 m² s^鈥? and hydrodynamic diameters between 1.5 and 2 nm probably representing smaller organic macromolecules. Aeration of the samples resulted in extensive agglomeration of NP to form larger (>50 nm) colloids, and a reduction of UV-absorbing material in the 0.5鈥? nm range. The complementary methods described have potential applications for investigating the fate and transport of NP in suboxic hotspots such as leachate plumes, wastewater treatment plants, and within the hyporheic mixing zone.