Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Department of Environmental Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, USA.
J Hazard Mater. 2019 Oct 15;378:120735. doi: 10.1016/j.jhazmat.2019.06.012. Epub 2019 Jun 5.
Silver, either in ionic or nanoparticulate form, is widely used in consumer products. However, silver sulfide (AgS) are more likely to be the form that Ag enters the environment. The retention of silver sulfide nanoparticles (AgS-NPs) in natural soils is critical for bioavailability and toxicity but remains unclear. Here, we examined the retention of AgS-NPs in 11 natural soils with varying properties using batch assays. More than 99% of AgS-NPs were retained in soil solids, irrespective of soil properties. Such high retention of AgS-NPs, at least partially, explained the distinct differences in phytoavailability performed in soil vs. liquid media in the literature. Nanoparticles containing Ag and S were identified in representative soil solids by high resolution transmission electron microscopy equipped with an energy dispersive X-ray spectrometer. Iron-rich acidic soil had a high dissolution of AgS-NPs ranging from 47.1% to 61.7% in porewater. In contrast to AgS-NPs, silver nanoparticles (AgNPs) and Ag in these soils were less retained (as described by Freundlich model) and the retention was closely associated with soil properties. These findings highlight the unique behaviors of AgS-NPs in natural soils.
银，无论是离子形式还是纳米颗粒形式，都被广泛应用于消费品中。然而，进入环境的银更可能是以硫化银（AgS）的形式存在。硫化银纳米颗粒（AgS-NPs）在自然土壤中的保留对于生物利用度和毒性至关重要，但目前仍不清楚。在这里，我们使用批量实验研究了 11 种具有不同性质的天然土壤中 AgS-NPs 的保留情况。无论土壤性质如何，超过 99%的 AgS-NPs 都被保留在土壤固体中。这种对 AgS-NPs 的高保留率，至少部分解释了文献中在土壤和液体介质中进行的植物有效性的明显差异。通过配备能量色散 X 射线光谱仪的高分辨率透射电子显微镜，在代表性土壤固体中识别出含有 Ag 和 S 的纳米颗粒。富含铁的酸性土壤中 AgS-NPs 的溶解率很高，在孔隙水中的溶解率从 47.1%到 61.7%不等。与 AgS-NPs 不同，这些土壤中的银纳米颗粒（AgNPs）和银的保留率较低（如 Freundlich 模型所描述的），保留率与土壤性质密切相关。这些发现强调了 AgS-NPs 在自然土壤中的独特行为。
