The intensity of lead and cadmium accumulation of milk thistle in various soils

Abstract

The article aims to study the intensity of heavy metals (lead, cadmium) accumulation in the vegetative mass of milk thistle on different soils. Based on the analysis of literary sources, it was found that milk thistle has a wide range of applications and, due to the presence of biologically active substances in its composition, has useful and medicinal properties. However, we have noted the plants liability for heavy metals accumulation which can affect the quality and safety of milk thistle. The purpose of the research is to study the intensity of the accumulation of heavy metals by the vegetative mass of milk thistle when grown in a modern feld crop rotation on different soils. The article presents data from scientifc literary sources and the results of our own feld and laboratory research. The study results reveal an excess of the maximum permissible concentrations of the toxicants in the vegetative mass under growing milk thistle on light gray podzolized, gray forest and dark gray podzolized soils with a lead content of 2.5 mg/kg–2.8 mg/kg and cadmium content of 0.2 mg/kg–0.22 mg/kg. In particular, an excess of the maximum permissible concentrations in the vegetative mass for lead by 1.97 – 2.86 times and cadmium – by 1.18 – 1.44 times was noted. The lowest content and the lowest coefcient of accumulation of lead and cadmium in the vegetative mass of milk thistle was observed on dark gray podzolized soils, and the highest – on light gray podzolized soils. It was also found that the hazard coefcient of lead and cadmium in the vegetative mass of milk thistle exceeded 1.0, which indicates the low quality of this raw material. The vegetative mass of milk thistle, which was grown on dark gray podzolized soils, was characterized by the lowest hazard coefcient, while the highest – on light gray podzolized soils. Key words: milk thistle, vegetative mass, lead, cadmium, soils, accumulation coefcient, hazard coefcient.