Applicability of portable XRF systems for screening waste loads on hazardous substances as incoming inspection at waste handling plants

In consequence of several European Union Directives, there is an increasing need for rapid and easy-to-handle screening tools to identify hazardous substances or to verify the absence of those substances. A field trial was executed to evaluate the capability of portable/handheld X-ray fluorescence (XRF) systems for screening waste loads on hazardous substances as incoming inspection at waste handling plants to characterise the waste material or to classify it by its key variables (critical parameters). For the field trial, six different waste materials were prepared: construction waste, shredder material, contaminated soil, waste wood, Pb granulate and slag from a municipal incineration waste. In total, eight different XRF instruments were evaluated. The results indicate that for screening analysis, the pretreatment of the sample is of minor relevance. Additionally, the results prove that the degree of homogeneity/heterogeneity of the material strongly influences the dispersion of the results of repeated measurements. The obtained results proved that for specific samples (e.g. organic matrices, elevated contaminant concentrations and high water content), an appropriate adjustment of the matrix effects and spectral overlap corrections are required to improve the quality of the XRF results. In the overall assessment, this analytical method can be recommended as a screening method for the analysis of waste, as more than 80% of the obtained results were situated within a predefined range of accuracy. Handheld XRF analysers are the detection method of choice for the initial analysis of elements in waste, as this method is fast, reliable, handy and cost-effective and allows easy checking of sample heterogeneity. Copyright (c) 2013 John Wiley & Sons, Ltd.