Dandelion Taraxacum linearisquameum does not reflect soil metal content in urban localities

Accumulation of selected heavy metals (Cd, Pb, Ni, Cr, Fe, and Zn) and phenolic metabolites (total soluble phenols, cichoric and caftaric acid) in dandelion organs (leaves, roots, inflorescences/anthodia) collected from six localities within the industrial town Košice (eastern Slovakia) were studied. Localities from the vicinity of a steel factory (Cd, Fe) and heavy traffic (Pb, Ni, Cr, Zn) contained the highest amount of individual metals in the soil but a significant correlation between soil and organ metal content was found only for Cr in the leaves (r² = 0.7679). The amount of Cd and partially Pb differed among localities in all organs and especially in the leaves and anthodia, indicating probably the impact of atmospheric pollution. The bioaccumulation factor was <1 for almost all metals, suggesting that given dandelion species is not metal accumulator. Translocation factor did not reach values close to or over 1 only for Cd, indicating a root-to-shoot movement of Pb, Ni and Zn though the impact of air pollution on leaves cannot be excluded. A strong correlation between leaf Cd and leaf total phenols, cichoric and caftaric acids was observed (r² = 0.7926, 0.8682 and 0.8830, respectively), indicating that phenolic metabolites act in the protection of dandelion against Cd excess. Overall, our data indicate low pollution of urban soil by Cd (5.53–113.8 ng g⁻¹) and partially by Cr and the suitability of above-ground organs of dandelion species for the monitoring of air pollution mainly by Cd. - Highlights: • Heavy metals and metabolites in dandelion from Košice (central Europe) were analyzed. • Low Cd or Cr in dandelion tissues in comparison with other cities were found. • Zn and Ni were stable in all organs but Cd and Pb varied, indicating air pollution. • Metals in leaves/roots yielded TF typically ≥1 but BAF was <1 for most metals. • Correlation between leaf Cd and phenols, caftaric and cichoric acids was observed. - Taraxacum linearisquameum seems to be suitable object for the monitoring of Cd and Pb air pollution and phenolic metabolites help it to cope with Cd deposition.