The ecological assessment of the purity of medicinal plant raw materials Thymus serpyllum L. in the Trans-Urals of the Republic of Bashkortostan

The paper presents the results of the study of heavy metals content in plant raw materials Thymus serpyllum L. growing in the vicinity of the village of Arkaim, Sibay, the Republic of Bashkortostan. The content of mobile forms of Cu, Ni, Mn, Co, Fe, Cd in soils did not exceed the maximum permissible concentrations, with the exception of Zn (1,87 MPC) and Pb (3,16 MPC). It was found that the most mobile element in the soil was Pb (59,4%), while Ni (0,07%) was less mobile. The soils of the studied territory were classified as permissible according to the degree of pollution, and the ecological situation turned out to be relatively satisfactory. The results of the statistical analysis showed that the concentrations of heavy metals in plant ash had a high variability (above 21%), with the exception of Co, which was characterized by an average variability (up to 20%). Cu content in Thymus serpyllum L. plants did not exceed acceptable values. There were exceeding of the maximum permissible levels for Zn (3,88–9,72 times), Fe (6,4–57,9 times), Ni (108–189 times), Cd (1,16–2,16 times), Co (3,7–5,6 times), Pb (4,6–10,8 times) in all organs of the plant Thymus serpyllum L. Mn concentrations exceeded the norms in the stems and roots of the species by 1,51–4,48 times, respectively. The most absorbed by plants Thymus serpyllum L. elements turned out to be Fe and Ni. In plants Thymus serpyllum L. Fe (124,3) and Ni (1567,5) belonged to the group of elements of energetic accumulation (I_A > 10), Zn (8,12), while Cu (8,04), Mn (4,44), Pb (2,08), Cd (1,75), Co (1,31) belonged to the group of elements of strong accumulations (I_A 1–10). In plants of Thymus serpyllum L. Cu, Zn, Ni, Fe, Mn, Pb were distributed by acropetal type (acropetal coefficient >1,0), while Cd, Co were distributed by basipetal type (acropetal coefficient <1,0).