关键词: 重金属污染, 土壤, 植物富集, 分布格局, 合肥

Abstract: This study examined the distribution of heavy metals in soils of the old town of Hefei City and the enrichment potential of heavy metals by four main greening species including Magnolia grandiflora,Osmanthus fragrans,Cinnamomum camphora, and Platanus acerifolia.Soil and biennial branch samples were collected in 36 sites in different types of green space in the old town. The contents of Pb, Cd, Hg, and Cr in the samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that soil Cd, Pb, and Hg contents in green space were 66.2, 3.6, and 3.4 times higher than the background value in the soil of old town, respectively, whereas Cr content was slightly lower than the background value, indicating that Cd pollution was the most serious in the old town. In terms of the heavy metal enrichment potentials, Hg was the most enriched by trees, followed by Pb and Cd, and Cr was the least. The enrichment ability of trees for Pb and Cd followed the order of O. fragrans >M. grandiflora>C. camphora>P. acerifolia.For Hg enrichment, they followed M. grandiflora>O. fragrans>C. camphora >P. acerifolia. For Cr enrichment, they followed C. camphora >P. acerifolia >O. fragrans>O. fragrans>M. grandiflora. The order of comprehensive enrichment ability of the four tree species to heavy metals was O. fragrans >C. camphora> P. acerifolia> M. grandiflora. The concentrations of Pb, Cd, Hg and Cr in the four tree species were below 4.0, 0.2, 0.45 and 0.6 mg·kg^-1, respectively, indicating great potential for heavy metal accumulation and storage.

Key words: heavy metal pollution, soil,  plant enrichment, distribution pattern, Hefei.