pXRF application in soil science

Nowadays, when soil pollution poses a worrisome threat to humanity, the need for soil protection is very pronounced with increasing requirements for methods that can quickly and accurately detect pollutants in the soil, especially metals. Portable X-ray fluorescence (pXRF) imposes itself as method with real-time and simultaneous multi- (total) element analysis, along with relatively low detection limits and relatively low cost. The goal of this research was to determine the concentrations of lead (Pb), nickel (Ni), chromium (Cr) and manganese (Mn) in referent soil samples by means of pXRF method and to determine the accuracy (RPD) and precision (RSD) of pXRF analyser using the referent soil samples. The research was based on analysis of 43 referent soil samples which were collected from 2009 to 2019 as part of participation of Analytical laboratory of Department of General Agronomy (Faculty of Agriculture, Zagreb) in Wageningen Evaluating Programme for Analytical Laboratories (WEPAL) within International Soil-analytical Exchange (ISE) program. Measurement was conducted by simple “point and shoot” technique on VantaTM handheld (portable) XRF analyser C Series (Olympus, USA, 2019). Results revealed that portable XRF analyser is capable of measuring Pb, Ni, Cr and Mn in ranges of concentrations (10.5 - 327 mg Pb/kg ; 18 - 70 mg Ni/kg ; 63 -255 mg Cr/kg ; 201 – 1435 mg Mn/kg) with excellent (RPD 0-10 %) to good (RPD 10-25 %) accuracy and acceptable precision (RSD < 20 % ; USA EPA, 2007) especially in clay soil samples. Also it is noticeable that poor accuracy (RPD > 50%) for investigated elements was determined in same soil samples with sandy texture.