Leaf Accumulation Capacity of Herbaceous Plants Growing on Fields Contaminated With Anthropogenically Induced Potentially Toxic Elements Under Natural Soil Conditions

Abstract

Estimation and knowledge of potentially toxic elements (PTEs) in soils and herbaceous plants are vital for ecotoxicological reasons. This study explored PTE accumulation in the aerial organ (leaf) of herbaceous plants in PTE-contaminated soils in a linear transect of three localities close to the Litavka River in Pribram, Czech Republic. Leaf accumulation answers questions on PTE hyperaccumulation and removal during phytoremediation. The study adopted the pseudo-total extraction (aqua regia soluble) of PTE contents (Cd, Cu, Zn, Pb, and Ni) of soil and leaf samples determined by inductively coupled plasma optical emission spectroscopy. Except for Ni, the contents of Cd, Cu, Pb, and Zn were above the permissible limits in soil following WHO with contamination factors ranging from moderate to serious contamination in the sites. Of the 118 herbaceous species in the sites, 43% (52 species) accumulated Cd above the WHO limit in leaves with Geranium pusillum Burm. f. having the highest content (0.84 mg kg⁻¹) while only Geum urbanum L. (132 mg kg⁻¹) and G. pusillum (166 mg kg⁻¹) were above the limit that supports the principal option to clean the infested soils. There was a low bioaccumulation of all plants indicated by a bioaccumulation factor less < 1 (BAF_leaf < 1) with PTE content lower than reported hyperaccumulator values. The hyperaccumulation status of PTE of plants stated by previous authors in leaves can be unreliable, under natural soil conditions, accumulations can even be lower than the permissible limits. Further studies requiring different soils and other plants are needed to make a reliable inference on which organs of plants support hyperaccumulation status.