The use of X-ray fluorescence spectrometry for the analysis of plants, especially lichens, employed in biological monitoring

Several analytical techniques are available for the elemental analysis of plants such as lichens used in pollution monitoring studies. This paper examines the advantages and disadvantages of one technique, X-ray fluorescence spectrometry, for determining the elemental content of lichen. The technique can be used for macro nutrients such as K and Ca and for trace metals such as Cu, Pb and Zn as well as for non-metals, especially S. Consideration is given to collection, preparation and analytical procedures for lichens using this analytical method. Data from studies using XRF are presented. Improvements are suggested with regard to sample preparation, and the limitations which prevent the method being more widely adopted are reviewed. The new generation of computer-assisted spectrometers have significantly lowered detection limits, so that background elemental levels in remote areas as well as enhanced levels near industrial activities can effectively be assayed in lichen or other plant samples.