Transfer of heavy metals (Cd, Pb, Cu and Zn) from roadside soil to ornamental plants in Nanjing, China

Roadside soil, dusts, and three ornamental plants-Begoniaceae (Begonia semperflorens Link et Otto), Tagetes (Tagetes erecta Linn.), and Salvia (Salvia splendens Ker-Gawle) were collected from urban arteries in Nanjing City, China. Concentrations of metals (Pb, Cd, Cu and Zn) were analyzed using inductively coupled plasma atom emission spectrometry and inductively coupled plasma mass spectrometry. Cd was the most important contaminant in roadside soil and dusts. Generally, Begoniaceae accumulated more metals than Tagetes and Salvia. The order of bioconcentration factor values for three kinds of plants were Cd > Cu > Zn > Pb, suggesting Cd was more easily accumulated by ornamental plants than Zn and Pb from soils to roots. The values of the translocation factor show the significant species specific characteristics on the ability of metals (Cd, Cu, Zn and Pb) translocation from roots to leaves. Begoniaceae was recommended as a bioindicator of heavy metals in the urban environment.