COMPARATIVE ASSESSMENT OF HEAVY METALS IN SUBURBAN VEGETABLE PLOTS OF CHANGCHUN, DEHUI AND NONGAN, NORTHEAST CHINA

Recently, enhanced urbanization and industrialization in China have greatly influenced the content of heavy metals in suburban agricultural soils. Concentrations of Pb, Cr, Cu, Ni, Zn and Cd in the top-soils (0-10 cm) from suburban vegetable soils in Changchun City (CC), Dehui County (DH) and Nongan County (NN) of Jilin were measured in the study. The median values of the heavy metals in all samples were 26.34, 58.26, 19.52, 26.94, 74.46 and 0.11 mg kg(-1) for Pb, Cr, Cu, Ni, Zn and Cd, respectively. Compared with the background value of Jilin soil, the concentrations of the heavy metals studied in vegetable plots exceeded their corresponding natural-background values. The variations of median concentrations for Pb, Cu and Zn in soils followed the order of CC > DH > NN. The results of principal component analysis (PCA) indicated that Cr and Ni concentrations were mainly of natural origin, while Cu, Zn and Cd were derived from anthropogenic activities, and Pb tended to be from both sources. The integrated pollution index (IPI) value of the metals varied from 0.90 to 2.74 with an average of 1.33, indicating that most of the soils were moderately contaminated by heavy metals. The findings presented here showed that the level of industry development is an important factor in determining the extent of heavy metal accumulation and the level of pollution in some suburban vegetable fields of CC, DH and NN was very high.