Department of Soil Science, North Carolina State University, Raleigh, NC 27695, USA.
J Environ Qual. 2011 May-Jun;40(3):667-78. doi: 10.2134/jeq2010.0140.
Soils provide long-term storage of environmental contaminants, which helps to protect water and air quality and diminishes negative impacts of contaminants on human and ecosystem health. Characterizing solid-phase chemical species in highly complex matrices is essential for developing principles that can be broadly applied to the wide range of notoriously heterogeneous soils occurring at the earth's surface. In the context of historical developments in soil analytical techniques, we describe applications of bulk-sample and spatially resolved synchrotron X-ray absorption spectroscopy (XAS) for characterizing chemical species of contaminants in soils, and for determining the uniqueness of trace-element reactivity in different soil microsites. Spatially resolved X-ray techniques provide opportunities for following chemical changes within soil microsites that serve as highly localized chemical micro- (or nano-)reactors of unique composition. An example of this microreactor concept is shown for micro-X-ray absorption near edge structure analysis of metal sulfide oxidation in a contaminated soil. One research challenge is to use information and principles developed from microscale soil chemistry for predicting macroscale and field-scale behavior of soil contaminants.
土壤为环境污染物提供了长期储存库，有助于保护水和空气质量，并减少污染物对人类和生态系统健康的负面影响。在地表广泛存在的众所周知的高度不均匀土壤的情况下，为了开发可广泛应用的原则，对高度复杂基质中固相化学物质进行特征描述至关重要。在土壤分析技术的历史发展背景下，我们描述了使用批量样品和空间分辨同步加速器 X 射线吸收光谱（XAS）来对土壤中的污染物化学物质进行特征描述，以及确定不同土壤微生境中痕量元素反应的独特性。空间分辨 X 射线技术为跟踪作为具有独特组成的高度局部化学微（或纳米）反应器的土壤微生境内的化学变化提供了机会。一个这样的微反应器概念的例子是对污染土壤中金属硫化物氧化的微 X 射线吸收近边结构分析。一个研究挑战是利用从小尺度土壤化学中获得的信息和原理来预测土壤污染物的大尺度和田间尺度行为。
