Comparative elemental analysis of organic and inorganic fertilizers using the nuclear analytical techniques: PIXE and RBS

Abstract The presence of trace elements in fertilizers raises concerns about food contamination and public health risks. This study investigates the elemental composition of organic (chicken droppings, cow (processed by earthworms), goat, sheep, and cow dung) and inorganic (NH 4 NO 3 , 28% N, and NPK 0.5% Zn ) fertilizers collected from the Zululand region of South Africa. Proton-induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) were used to quantify elemental concentrations. A silicon lithium (Si (Li)) X-ray detector was engaged in PIXE to identify trace elements with atomic numbers greater than Z > 10. The results revealed the presence of 27 Al, 28 Si, 30 P, 32 S, 35 Cl, 39 K, 40 Ca, 48 Ti, 53 Cr, 54 Mn, 55 Fe, 56 Zn, 79 Br, 87 Sr, 91 Zr, and 85 Rb with average concentrations of 33, 12, 4, 17, 13, 50, 36, 2.1, 0.13, 0.69, 29.3, 1.2, 0.28, 0.13, 0.073, and 0.12 ppm ×10 3 , respectively. The proton backscattering spectrometry in RBS was engaged to determine nitrogen in organic fertilizers, and its concentration range from 0.9 to 1.2 at%. Spectral analysis was performed using GeoPIXE II software. The results demonstrate the applicability of nuclear analytical techniques for fertilizer quality assessment and reveal the presence of potentially toxic elements, highlighting the need for regulatory monitoring and safer, sustainable agricultural practices.