Ecological-geographical analysis of vegetation of near-roads zones of transport corridor Lviv–Krakovets

Abstract

In the article, the eco-geochemical analysis of flora on roadside areas of highway M-10 Lviv-Krakovets is made. In the foliage of following tree species Common hornbeam (Carpinus betulus L.), English oak (Quercus robur L.), Common beech (Fagus sylvatica L.), Common ash (Fraxinus excelsior L.), Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.), using atomic-absorption methods, there were revealed such heavy metals as Pb, Zn, Co, Cu, Ni, Mo, Cr, Mn, V, Ba, Sr, Zr, Fe, Ti, Sn. The analysis of literary sources by Voloshyn, Sobechko, Bessonova and ours investigations reveals that in different areas the content of heavy metals (HM) in the foliage of tree species differs significantly. In addition, it has been investigated the content of chemicals in the foliage of roadside trees along highway Lviv-Krakovets and compared with world clarke indices. Content of Pb, Zn, Mn, V in the foliage of roadside trees is lower than showing of world clarkes, what is caused by characteristics of parent rocks. Elements that exceed world clarkes are Ba, Cu, Ni, Mo, Sr, Ti, Zr and Cr, their content in foliage of tree species varies from 1,2 to 16,7 mg/kg of dry weight. In the article, the accumulation coefficients are calculated. These coefficients confirm accumulation of car pollutants in roadsides and adjoining areas. There is made an investigation of general biological and discrete (by root surface and foliage surface) absorption of 15 chemical elements and as a result several species, which have the highest accumulation coefficients, are set apart. In the foliage of roadside tree species, the general biological absorption coefficients (GBAC) of technogenic (road) pollutants are counted. It has been determined that the maximum GBAC values immanent to Ni and Ва are 10,1 and 3,5 correspondingly (Common hornbeam), Cu – 7,7, Mn – 2,7 and Мо – 1,4 (English oak) and Sr – 1,4 (Common ash). According to the content and distribution of heavy metals in the foliage of roadside trees, it was build the descending rows according to intensity of HM absorption by different tree species. It has been counted the intensity with what tree species absorb road pollutants, Pb absorbs Common ash, Scots pine, Zn, Co, Cr, Sr – Common ash; Ni, Ba – Common hornbeam; Cu, Mo, Mn, V, Zr – English oak; Fe, Ti – Norway spruce. It has been counted the discrete (areal and root) absorption of HM by tree species. It is known from literary sources that foliage does not accumulate Pb by areal way, that is why the value of this HM is considered as constants and according to certain methodological ways is counted areal and root absorption. The discrete biological absorption coefficients (DBAC) of technogenic (road) pollutants by different tree species in roadsides are different. Deciduous tree species in contrast to pinophyta, by areal way accumulate Mо – 0,33 (Common hornbeam) – 0,95 (English oak), partially V – 0,17 (English oak), Zn – 0,14 (Norway spruce). DBAC Со in foliage of tree species varies from 0,33 (English oak) to 0,73 (Common beech), Cu – 0,52 (Scots pine) – 0,99 (English oak, Common hornbeam), Ni – 0,23 (Scots pine) – 0,99 (Common hornbeam, English oak, Common beech, Norway spruce), Mn – 0,61 (Common ash) – 0,98 (English oak, Norway spruce), Ва – 0,43 (Common hornbeam) – 0,92 (English oak, Norway spruce), Sr – 0,64 (Common hornbeam) – 0,94 (English oak, Norway spruce). The most actively foliage absorbs Cu, Ni, Mn, Со (in 100 % of samples); partially – Ba, Sr (80 %); Mo (40 %); V і Zn (20 і 10 %). It has been proposed several tree species for forest plantation, which have the highest biological absorption. The highest intensity of general biological absorption of HM have English oak, Common hornbeam, Common ash, Common beech, Norway spruce, which absorbs Ni, Cu, Ba, Mn, Sr, Mo, Co, Fe, and this considerably reduce pollution in roadsides and adjoining areas.