Levels of heavy metals in the «soil – medicinal plants» system in relation to the geographical location and ecological and genetic zone of the Irtysh river floodplain

Abstract

The article provides the material on the levels of zinc, copper, and cadmium in the «soil-medicinal plants» system in relation to the territorial location and ecological and genetic zonality of the Irtysh river floodplain. The heavy metals (zinc, copper, cadmium) contents of medicinal plants growing in the Irtysh river floodplain (Semey, Ozerki village) were assessed in order to determine the safety of the medicinal plant therapeutic application. Standard procedures for collection, transportation, preparation and storage of soil and plant samples and also for chemical analysis were applied in the study. The contents of all studied chemical elements in the total aggregate of medicinal plants descend as follows: zinc 45.8 mg/kg; copper 6.2 mg/kg; cadmium 0.23 mg/kg. As is evident from the findings (Glycyrrhiza glabra (Zn = 17.3 ± 0.79 mg/kg); Inula helenium (Cu = 2.3 ± 0.17 mg/kg); Taraxacum officinale (Cd = 0.12 ± 0.01 mg/kg)), no average values were found to exceed the maximum permissible limits. This information is certainly essential for selecting sites for harvesting safe herbal raw materials; also, medicinal plants can be considered as indicators of environmental pollution. This determines the rationale for research study in this direction and puts forward a vital task: to strengthen quality control of herbal medicinal raw materials taking into account the content of heavy metals.