Combining leaching methods, mineralogical and (micro)spectroscopic techniques to assess the origin and fate of heavy metals in contaminated soils and sediments

摘要

The present paper wants to give an overview of the application of mineralogical and spectroscopic tools in the investigation of contaminated soils and sediments, and illustrate the advantage of using these techniques in combination with more conventional leaching procedures. Mineralogical sample investigations by XRD, optical microscopy an electron microscopy are used to identify and quantify minerals which play a role in heavy metal sequestration and release. Electron probe X-ray microanalysis (EPMA) equipped with an energy-dispersive X-ray (EDX) detector can be used to simultaneously detect the morphology and element composition of a sample and has successfully been applied in sediment research, while spectroscopic tools such as X-ray adsorption fine structure (XAFS) spectroscopy give information on the coordination chemistry of metals. The combination of leaching tests with mineralogical and spectroscopic sample investigation can provide information on the reactivity and solubility of minerals in soil and sediment samples. Besides the improved interpretation of the results of leaching tests for soils/sediments in which minerals are identified, the information concerning the reactivity of minerals is an important tool to evaluate the risk associated with contaminated soils and sediments.