Bioindication potential of trees and shrubs leavesof Temirtau city

In many regions of Kazakhstan there is an issue of air pollution by heavy metalswhich are major components of emissions from enterprises. Heavy metals areintensively released in the atmosphere of Temirtau city by a man-made technogenicstream and are related to the activities of steel, chemical, construction and thermalpower industries that dominate in the city as well as a well-developed transportationnetwork. Heavy metals are among the most hazardous pollutants because of theirphysiological and biochemical features. Therefore, a control over the content of heavymetals in the biosphere is an integral part of a set of environmental measures. Onepromising approach to biological characteristics of air pollution is to assess the stateof wood plants according to their degree of resistance to industrial emissions.In this paper, the content of heavy metals in the leaves of trees and shrubs ofTemirtau city under different anthropogenic load was studied. Identified fluctuationsof heavy metals in the leaves of trees and shrubs are due to the combined influence ofinternal (genetic) and external (environmental) factors. The content of heavy metals inthe leaves of trees and shrubs of city Temirtau at different anthropogenic load varies.Plants growing in industrial and transport zones accumulate more heavy metals thanin residential and recreational areas, and this coincided with soil contamination. Theconcentration of heavy metals in the leaves of trees and shrubs of Temirtau exceeds theirclarke in terrestrial vegetation, marking the species specificity. The highest averageconcentration of zinc is typical of Betula pendula Roth., Populus alba L., copper -Crataegus oxyacantha L., Populus alba L., cadmium - Populus nigra L., Populus albaL. and lead - Eleagnus angustifolia L., Syringa vulgaris L. leaves.Thus, the leaves of trees and shrubs of Temirtau city accumulate heavy metal verywell, which shows the intensity of development pressure on urboecosystems by thesecontaminants as well as their bioavailability. On the basis of a significant heavy metalsaccumulation by wood plants leaves as well as the values of PMA and ash content,the most suitable species for the informative display of heavy metals air pollution inTemirtau are leaves of B. pendula Roth, A. negundo L., E. angustifolia L., and leaves ofPopulus type trees. Being cumulative bio-indications, thus, resistant to anthropogenicstress, they can be recommended for use in the landscaping of the city as air filters.

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