Influence of past industry and urbanization on elemental concentrations in deposited dust and tree leaf tissue

Abstract

Elemental concentrations of deposited dust and leaf tissue are often used to assess the level of contamination, and for monitoring air pollution. Leaves of Platanus x acerifolia, Fraxinus excelsior and Acer campestre were used to assess the amount of deposited dust and the elemental concentrations of deposited dust and leaf tissue in and around the city of Miskolc, Hungary. Samples were collected from the nearby cement and steel factories and from urban, suburban and rural areas along an urbanization gradient. Both the cement and steel factories were in the suburban area of Miskolc, an influence the air quality of the city. The concentrations of Al, Ba, Cd, Cr, Fe, Na, Pb, Si, Sr and Zn were determined in the deposited dust and leaf tissue, using MP-AES. We found significant differences in the amounts of deposited dust between suburban and rural areas. There were no significant differences among the other areas compared to each other. Canonical discriminant analysis showed a good separation of areas and species based on the elemental concentrations of deposited dust and leaves. In the deposited dust, significant differences were found among studied areas in the case of Al, Ba, Cd, Cr, Fe, Na, Pb, Si, Sr and Zn. There were no significant differences among species in the elemental concentrations of deposited dust, with the exception of Na. However, the Al, Ba, Cr, Cu, Fe, Mn, Si, Sr and Zn concentrations in leaf tissue differed significantly among the studied areas. We found significant differences among leaves of various species in the case of Ba and Si. The organic matter content of leaf tissue was positively correlated with Zn concentration. In the cases of other elements there was no significant correlation between the organic matter content and the elements’ concentration in leaf tissue. Our results suggested that industrial activities and urbanization caused remarkable air contamination. Our findings suggest that the dust deposits on leaf surface may be useful indicators of atmospheric element air pollution. The reconstruction of abandoned industrial buildings are needed because, in addition to general urbanization, they have been a potential air pollution source, and still remain so.