Heavy metals in the system «soil - wild medicinal plant» (on the example of <i>Cichorium intybus</i> L.)

Abstract

This paper discusses the features of the heavy metals content in medicinal plant raw materials Cichorium intybus L. in the conditions of the Trans-Ural region of the Republic of Bashkortostan. Variational and statistical indicators of the heavy metals content in soils and plants are calculated. The coefficients of variation of gross and mobile forms of heavy metals in soils are high (above 21%), the exception was the gross form of Fe, which is characterized by low variation (up to 10%). The content of gross forms of heavy metals in soils exceeded the maximum permissible concentrations of Cu (18 times), Zn (13 times), Cd (2 times), Co (1,2 times) in the sample area 2, and Mn (1,2 times) and Cu (2,5 times) in the sample area 3. The content of mobile forms of Fe and Pb in soils did not exceed the maximum permissible concentrations. The samples had an increased level of mobile forms in Cu (39 times), Zn (2,1-4,3 times), Ni (1,12 times), Mn (2,3-2,6 times), Co (1,3-1,5 times), Cd (2,1-5,7 times). The degree of mobility of heavy metals in soils decreases in the series Pb Co Cd Zn Mn Cu Ni Fe. According to the degree of Zc contamination, the studied soils were classified as permissible (Zc from 0,2 to 5,2), with the exception of sample area 2, which was classified as highly hazardous (Zc up to 48,2). The level of contamination of the soil cover is minimal, and the environmental situation is relatively satisfactory (Zc from 0,2 to 5,2), with the exception of test area 2, where the level of pollution is high and the environmental situation is critical (Zc up to 48,2). Plants of Cichorium intybus L. are contaminated with Ni, Cd, Fe, and concentrations of Pb and Mn in plants did not exceed the maximum permissible levels. The most absorbed elements were Fe (25,7) and Cu (65,4), which belonged to the group of elements of energetic accumulation (accumulation index 10), Ni (8,9), Pb (4,7), Zn (2,2), Cd (2,06), Co (1,1), and Mn (1,06) related to a group of elements of strong accumulation (accumulation index from 1 to 10). In plants of Cichorium intybus L. Cu, Fe, Ni, Mn, Cd, Co are distributed by acropetal type (acropetal coefficient 1,0), and Zn and Pb are distributed by basipetal type (acropetal coefficient 1,0). The value of biogeochemical activity in the plant Cichorium intybus L. varies from 47,4 to 728,3.