Leaves of trees and shrubs as bioindicators of air pollution by particulate matter in Saint Petersburg

Abstract

Accumulation of chemical elements by leaves of trees and shrubs in urban (Central District of St. Petersburg) and background habitats were studied. To determine proportion of pollutants accumulating on the surface of leaves, chemical content of washed and unwashed leaves were analyzed. The results of the study showed that big part (19-62%) of pollutants is deposited on the surface of leaves of urban lindens, and only 10% on the surface of leaves from background places. Average difference between quantity of particulate matter for them is 4 times. Tilia cordata and Ulmus laevis has the highest value of ash content between washing and washing leaves. The level of contamination (Kk) showed high values for Fe (8.83), Co (7.47), Cr (5.62), Pb (4.31), Zn (3.04) for unwashed leaves of urban lindens; for the washed leaves this index slightly increased only for Fe (3.12) and Pb (2.13). Accumulative ability depends on the structure of leaf blade of each species, and the ecological situation of the habitat. Ulmus laevis, Tilia cordata, Populus sp., and Rosa rugosa accumulate more pollutants, and can be recommended for protective green plantings. Tilia cordata, as the most common species in the city green spaces, can be used as an indicator of the level of atmospheric pollution.