Heavy Metal Uptake and Bioaccumulation in Chives (Allium schoenoprasum L.)

Abstract

This study aimed to evaluate the uptake and accumulation of trace elements in three cultivars of chives (Allium schoenoprasum L.; Bohemia, Pobrežná, and Pražská) grown under identical field conditions in Veľká Mača (Slovak Republic), in order to determine their food safety and suitability for cultivation in moderately contaminated soils. Pseudo-total and mobile forms of heavy metals in soil were determined, along with metal concentrations in plant leaves, using microwave-assisted digestion followed by flame and graphite furnace atomic absorption spectrometry. The soil exhibited elevated pseudo-total concentrations of Zn, Ni, and Cd, with Cd and Pb mobile fractions exceeding regulatory critical values, indicating potential soil–plant transfer risk. Despite these conditions, all chive cultivars accumulated essential micronutrients (Fe, Mn, Zn, Cu) within nutritionally relevant ranges, while concentrations of Pb and Cd in fresh biomass remained below European food safety limits (Commission Regulation (EU) 2023/915). Significant inter-cultivar differences (p < 0.05) were observed, particularly for Fe, Zn, Pb, and Cd. Principal component analysis revealed clear cultivar clustering driven by micronutrient content and Pb accumulation. Bioaccumulation factors were <1 for all elements except Cd (0.43–0.65), confirming low overall metal transfer from soil to plants, with moderate Cd uptake typical for Allium species. The results demonstrate that A. schoenoprasum cultivars differ in trace element uptake capacity and can be safely cultivated even under moderately contaminated soil conditions. These findings support the importance of cultivar selection and soil monitoring to ensure both nutritional value and food safety in Allium crops.