Abstract:

The soil pollution situations by heavy metals in various green space functional regions and their enrichment characteristics in seven plant species, including Salix matsudana, were investigated and comprehensively evaluated by means of field survey and laboratory experiment analysis. The results showed that the pollution degree of Zn, Cu, Cd and Pb in Harbin was different. Of the four kind heavy metals, Cd contamination was the heaviest and reached the severe pollution degree. The main source of soil heavy metal pollution in Harbin was derived from waste containing Zn, Cu, Cd and Pb discharged in industrial areas, automotive emission and the tire abrasion. The pollution level of green space functional regions gradually decreased in the following order: industrial zone, traffic areas, Songhua River area, urban park area, farm land, forest and nursery land. Among the main urban greening tree species in Harbin, Populus simonii enriched more Zn, Cu and Cd than the other tree species, therefore, P. simonii could be selected as an important species to repair heavy metal pollution soil. The other tree species, such as Pinus koraiensis, S. matsudana and Pyrus ussuriensis, also enriched to some less degree the three heavy metals and thus could be selected as alternative ones for restore the contaminated environment.

Key words: soil heavy metal, plant enrichment, Harbin city, green space