Scientific publications

The concentrations of heavy metals (Cu, Zn, Fe, Mn, Pb, Cd) in labile and acidsoluble form in soils and their content in coltsfoot (Tussilago farfara L.) were studied in the surroundings of various industrial enterprises in Tyumen. Soil and plant samples (n=6 each) were collected in a control site and near a highway, an engine plant, an oil refinery, a battery factory, and a steel mill. The involvement of the metals in air-borne migration was estimated by their content in coltsfoot. Heavy metal content in coltsfoot leaves was analyzed in two variants: with and without washing with distilled water. Samples were analyzed by atomic absorption spectroscopy. Cu, Zn, Fe, Mn, and Pb content in soil samples exceeded the control up to 6-fold. Pb content in soils at the battery factory exceeded the MPC 5.8-fold. Heavy metal lability in soils decreased in the following order: Mn > Zn > Cu > Fe. The concentrations of all the metals both in soils and plants were the highest at the battery factory and the steel mill. Metal accumulation by plants decreased in the following order: Fe > Zn > Cu > Mn > Pb > Cd. The bioconcentration factor in washed coltsfoot leaves declined in the Cu > Zn > Cd > Pb > Mn > Fe sequence, while the actual biogeochemical mobility decreased in the Fe > Cu > Zn > Pb > Cd > Mn sequence. The contribution of Cu, Zn, Fe, and Mn air-borne transfer to their accumulation in plants, which was estimated by the difference of metal concentrations before and after washing, ranged from 10 to 73 %. Air-borne migration was the most pronounced at the highway and the steel mill. Iron accumulation in plants showed the greatest connection to airborne industrial pollution as compared to other metals studied. These results indicate the importance of the air-filtering role of plants and prove that plants from urban habitats must not be used for medicinal or agricultural purposes. Accumulation of heavy metals from air-borne industrial pollution by plants is evidence of additional toxic effect of pollutants in the urban environment and suggests that plant samples for ecological research have to be pre-treated.