Accumulation of cadmium in the edible parts of seven vegetable species grown in Cd-amended soil and Cd-contaminated soil

摘要

Seven vegetable species (rape, Chinese leek, pakchoi, carrot, radish, tomato and cucumber) were grown in a Cd-amended pot experiment and a Cd-contaminated field trial to study the accumulation of Cd in the edible parts of these vegetables under different conditions. Furthermore the relationship between Cd concentrations in soil and vegetables were considered. The soil was amended with CdSO<,4> to obtain a range of six concentrations (0, 0.3, 0.6, 1.0, 1.5, and 2.0mg·kg<'-1>) in the pot experiment and the Cd concentration in the soil of field trial was 2.55mg·kg<'-1>. Cd concentrations in the edible parts of seven vegetables increased linearly with the increasing concentration of Cd added to the soil, and the slope of the regression lines varied by 28 fold among the seven vegetable species, indicating large differences in the characteristics of Cd accumulation. Cd concentrations were above the national allowable limit in pakchoi, Chinese leek, rape, carrot and tomato at a Cd addition level of 2.0mg·kg<'-1>. In the field trial, Cd concentrations in the edible parts of the seven vegetables ranged from 0.01 to 0.1mg·kg<'-1> and were below the national allowable limits. Cadmium concentrations in the selected vegetables of the pot experiment were much higher than those from the field trial. It is clear that the bioavailability of Cd in the soil in the field trial was much lower than that of the freshly added Cd in the pot experiment.