Use of nuclear and nuclear-related analytical techniques in studies of trace and minor elements in air pollution

Abstract

Among nuclear and nuclear-related analytical techniques, neutron activation and X-ray fluorescence analysis are particularly useful for environmental studies owing to their non-destructive character and multi-element capability. In this work, procedures for k₀-standardized instrumental neutron activation analysis (INAA) and energy-dispersive X-ray fluorescence (EDXRF) spectrometry for trace and minor elements in air pollution studies were investigated. The methods applied were validated by the analysis of suitable reference materials: NIST (National Institute for Standards and Technology) SRM 1633a Coal Fly Ash, NIST SRM 1570 Spinach, NIST SRM 3087 Metals on Filter Media and BCR (Community Bureau of Reference) CRM No. 128 Fly Ash on Artificial Filter. Using INAA, 20 experimentally obtained elemental values out of 21 certified and all 29 experimentally obtained values compared with ‘consensus’ values (for the elements where no certified numbers are available) in two SRMs were statistically indistinguishable. Also, the contents of 28 elements in candidate NIST SRM 1573a Tomato Leaves are reported. The EDXRF results were statistically indistinguishable from certified values for eight out of nine elements in NIST SRM 3087. The detection limit for this method is around at 0.1 µg cm^–2 per element, so in BCR CRM No. 128, which is intended for ambient air pollution data, only Fe and Zn out of 14 elements reported in the certificate were detected with acceptable precision (i.e., 10%) owing to the very low air particulate matter loading, lying in the region of only 250 µg cm^–2.