| الوصف: |
To evaluate the impacts of vegetable and soil variables on phytoaccumulation of arsenic (As), cadmium (Cd) and chromium (Cr) and identify their interactions and predictors, 33 paired soil-vegetable samples were collected from the production areas of celery (Oenanthe javanica), green onion (Allium), pak choy (Brassica rapa subsp. chinensis), rape (Brassica campestris L.) and spinach (Spinacia olearacea) in the Wuqing District of Tianjin, China. The concentrations (mean ± sd in mg kg-1) of As, Cd, and Cr were 12.9 ± 2.4, 0.21 ± 0.19, 68.2 ± 11.2 in soils, respectively, higher than their soil backgrounds, and 0.19 ± 0.13, 0.17 ± 0.11, and 1.33 ± 0.94 in shoots (leaves & stems) of all vegetables, respectively. Only Pak Choy’s Cd was significantly higher than its soil concentration and threshold. All vegetables, except green onion, with the lowest concentration of As, Cd, and Cr have been heavily contaminated with Cr. For all vegetables except spinach, Cd concentration in shoots can be well predicted with 0.1M HCl extracted soil Cd (clCd) (R2 > 0.75) with soil clNi; and shoot Cr concentration with shoot Fe (stFe) for celery, pok choy, rape, and spinach (R2 > 0.90).Generally, the concentration of As, Cd, and Cr in shoots depends not only on the availability of their specific forms in soil and soil pH but also on the interactions with other elements (especially Fe) in shoots, despite their variations with vegetable species. Both Cd and Cr have a high accumulation potential, which can be better predicted with either 0.1M HCl extractable soil Cd or Fe concentration in shoots. So, how a trace element interacts with other ingredients and its specific form in the soil should be seen as essential factors in how it gets into the shoots. |
