关键词: 土壤质量, 评价原则, 评价方法, 土壤质量指标

Abstract: Six seasonal vegetable species (lettuce, pepper, eggplant, cauliflower, tomato and welsh onion) and soil samples were collected from the vegetable growing farmland of Zhangshi wastewater irrigation area for Cd analysis. The uptake and accumulation ability of Cd in the edible part of the vegetable was evaluated using overproof multiple method, and the enrichment coefficient (EE) and translocation coefficient (TC) was employed to assess the efficiency of Cd uptake and transportation from soil to vegetables. Results indicated that Cd concentrations in the edible parts of lettuce, pepper and eggplant were higher among the six vegetables investigated, being 4.01, 1.78 and 1.24 mg·kg^-1 DW, respectively. The overproof amount of Cd in the edible part of these vegetables corresponded to 1.92, 2.28 and 2.01 times of that of the national food limited standards (0.20 mg·kg^-1 FW for leaf vegetables, and 0.05 mg·kg^-1 FW for solanaceous vegetables). Cd concentrations in the edible part of the rest vegetables were within the national food limited standards. The Cd concentration was 1.02, 1.20 and 0.83 mg·kg^-1 DW for tomato, cauliflower and welsh onion, respectively, with EE of 0.28, 0.36 and 0.52, respectively, which matched to the standard for low accumulated vegetables. EE was higher for lettuce with a value of 1.26, which indicated a comparatively large eco-risk if lettuce is to plant in Zhangshi soil or soil with similar Cd concentration level.

Key words: Soil quality, Evaluation principle, Evaluation method, Soil quality indices