Abstract: To understand the heavy metal pollution in soils of the shelterbelt along the Hefei Loop Expressway and the heavy metal accumulation ability of typical tree species (Populus canadensis, Koelreuteria paniculata, Ligustrum lucidum, Nerium oleander, and Salix babylonica) in the shelterbelt, we collected xylem samples from trunks and branches and soil samples from 60 sampling points in 12 sampling strips perpendicular to the shelterbelt. The concentrations of five kinds of heavy metals (Pb, Cd, Hg, Cr, and As) were measured by inductively coupled plasma emission spectrometry (ICPAES). The results showed that the concentrations of those five kinds of heavy metals in the soils all exceed the background values. The average concentration of Cd in the soil was 15.3 times of the background value. The concentrations of heavy metals in the soil tended to decrease with increasing distance from the expressway. Within the range of 35 m from the expressway, the comprehensive potential ecological risk of soil decreased significantly with increasing distance, but tended to be stable beyond 35 m from the expressway and was reduced to a slight level. The comprehensive enrichment ability of the five tree species to heavy metals was declining with an order ofNerium oleander, Ligustrum lucidum, Koelreuteria paniculata, Salix babylonica, and Populus canadensis.

Key words: heavy metal pollution, soil, plant enrichment, highway traffic.