MACROCHEMISTRY AND MICROCHEMISTRY OF TRACE-METALS IN VITRIFIED DOMESTIC WASTES BY LASER-ABLATION ICP-MS AND SCANNING ELECTRON-MICROPROBE X-RAY-ENERGY DISPERSIVE SPECTROSCOPY

Management of domestic wastes often relies on incineration, a process that eliminates large amount of wastes but also produces toxic residue s that concentrate heavy metals. Those hazardous secondary wastes requ ire specific treatment. Vitrification is seen as a powerful way to sta bilise them. However, concern exists about the long term behaviour of these glass wastes and the potential release of toxic species into the environment. The answers will come with further investigation into th e physico-chemical evolution of the vitrified wastes and the mobility of hazardous elements within the matrix with appropriate analytical me thods. Laser ablation coupled with inductively coupled mass spectromet ry (LA-ICP-MS) is a challenging technique for the chemical analysis of trace elements in solid materials. This paper presents an evaluation of the potential of LA-ICP-MS for macro and microanalysis of trace met als in domestic vitrified wastes with regards to other physical analyt ical techniques of solids such as scanning electronprobe X-ray energy dispersive spectroscopy (SEM-EDXS). Two typical samples, vitreous and crystallised, are used to compare the analytical performances of the t wo techniques. SEM-EDXS was used for mineralogical characterisation an d chemical analysis of the mineralogical phases. Relative micro-analys is and bulk quantitative analysis of 30 major, minor and trace element s was performed by LA-ICP-MS: precision was between 10 and 20% for mos t elements and quantitative analysis proved possible with an accuracy of 20% and relative detection limits of 0.1 mg kg(-1). (C) 1998 Elsevi er Science B.V. All rights reserved.