Characteristics and Ecological Risk Assessment of Heavy Metal Pollution in Vegetable Soils of Guangzhou Urban Districts

【Objective】This paper was to study the pollution characteristics and ecological risk of heavy metals in vegetable soils of Guangzhou urban districts, which have been impacted by the development of urbanization. 【Method】35 soil samples were collected from 7 central districts in Guangzhou to analyze the concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. Pearson correlation coefficient, principal component analysis and potential ecological risk index were used to study the sources, contents, and ecological risk of heavy metals in soil.【Result】The average contents of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in vegetable soils were 15.93, 0.11, 66.37, 46.84, 0.62, 35.19, 110.09 and 154.95 mg/kg, respectively, all of which were higher than the background values. Comparing with Environmental Quality Standard for Soils, the contents of all metals (except Cr) exceeded the standard values to different extent , with the exceeding rate of Hg being the highest (37.1%). The pollution sources of heavy metals in vegetable soil were compound artificial pollution sources. Some vegetable soils in Guangzhou urban districts were at a high level of ecological hazard and Hg was the main risk element.【Conclusion】Some vegetable soils in Guangzhou urban districts were no longer suitable for vegetable cultivation.