Studies on the background levels of heavy metals in major vegetables in Guangzhou vegetable garden soils

Based on the investigation of background levels of heavy metals (lead, mercury, cadmium, chromium and arsenic) in Guangzhou vegetable garden soils and in some popular vegetables, the contents of the five elements in pakchoi, chinese kale, leaf mustard, flowering chinese cabbage, turnip, chinese cabbage, watercress, head cabbage, celery, kidney been, pea, head lettuce, longleaf lettuce, spinach and tomato were detected. With manifold analytical method, we had done some comparison among different vegetables. The content ranges of the five elements in 15 vegetables are as follows (fresh mass): Pb 0.002~0.148 mg/kg, Hg ND~0.006 mg/kg, Cd 0.001~0.034 mg/kg, Cr 0.002~0.150 mg/kg, As 0.001~0.070 mg/kg. The results showed that the background levels of Pb, Hg, Cd, Cr and As in various vegetables have something to do with the discrepancy of vegetable species as well as with the discrepancy of soil condition in Guangzhou vegetable garden soils.