Instrumental neutron activation analysis of Rosmarinus officinalis : seasonal variations of major, trace, and rare earth elements

The elemental composition of medicinal plants is a key factor influencing their nutritional value, therapeutic properties, and environmental interactions. In this study, Instrumental Neutron Activation Analysis (INAA) was employed to investigate the seasonal variations in the concentrations of major, trace, and rare earth elements in Rosmarinus officinalis collected from the Medea region (Algeria) during autumn, winter, spring, and summer. The INAA technique enabled the simultaneous determination of multiple elements with high sensitivity and accuracy, without requiring chemical pre-treatment. The results revealed significant seasonal variations in elemental concentrations. Major elements such as calcium (Ca) and potassium (K) showed elevated levels during spring and summer, reflecting enhanced physiological activity and nutrient uptake. Trace elements, including iron (Fe), zinc (Zn), cobalt (Co), and chromium (Cr), exhibited increasing trends from autumn to summer, suggesting strong dependence on environmental conditions. Additionally, rare earth elements (REEs), such as lanthanum (La), cerium (Ce), and europium (Eu), showed noticeable seasonal fluctuations, indicating their geochemical mobility and plant uptake dynamics. Toxic elements such as arsenic (As) and antimony (Sb) remained at low concentrations, suggesting minimal environmental risk. Overall, the study highlights significant seasonal variations in the elemental composition of R. officinalis and provides insights into plant–environment interactions and elemental accumulation patterns.