Regional characterization of elemental food composition (cabbage and potato) from lithium-bearing agricultural areas of northern Portugal (Guarda region)

This study focuses on a regional characterization of the elemental composition of food and soil–plant transfer in crops cultivated in lithium-bearing areas. It evaluates the chemical composition of cabbage and potato, irrigation waters, and agricultural soils collected in Eastern center of Portugal (Castanho and Alvarrões). A multi‑element analysis (Li, Be, B, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Sn, Tl, Pb, Fe, Mg, Ca, Na, P, and K) was conducted using ICP-MS and ICP-OES. Li concentrations were below 37 µg/L in irrigation water and between 58 and 259 mg/kg in the analyzed agricultural soils, providing context for a geochemical enrichment of the study region. Cabbage consistently exhibited higher concentrations of chemical elements, particularly for Li (24.4 – 4770 µg/kg FW), B (1518 – 10196 µg/kg FW), Sr (2921 – 19844 µg/kg FW), and K (2297 – 7738 mg/kg FW), and higher soil–plant transfer efficiency than potato, reflecting crop‑specific accumulation behavior. For most potentially toxic elements, soil–plant transfer was limited in both crops. Dietary relevance was assessed through a preliminary exposure screening. Estimated exposure to most elements was low under local consumption conditions. This study provides region‑specific reference information to support future monitoring studies as Li extraction strategies evolve.