Determination of high Zn and Pb concentrations in polluted soils using energy-dispersive X-ray fluorescence spectrometry

A method of determination of high Zn and Pb concentrations by means of EDXRF (energy-dispersive X-ray fluorescence spectrometry) is presented. Zn and Pb concentration in soil samples from contaminated areas ranged within a limit of Zn: 800–2000ppm and Pb: 200–600ppm. Soil analysis was conducted directly after the samples had been dried and powdered, as well as in situ in polluted areas. Due to the absence of the certificate reference materials for soils with such high Zn and Pb concentrations, samples of soil with the Pb and Zn amounts determined using the AAS method were used to perform calibration. The obtained detection limits are 30ppm and 19ppm for Zn and Pb, respectively. Because of the high analytes concentration and material heterogeneity, the repeatability of the results was examined according to the sample holder’s various positions in EDXRF analyzer; repeatability the of the results while putting into the sample holder and out of it, together with the repeatability of making the calibration. The results obtained using the EDXRF method were compared to these obtained using AAS and wavelength-dispersive X-ray fluorescence spectrometry (WDXRF).