• 中文核心期刊
  • CSCD来源期刊
  • 中国科技核心期刊
  • CA、CABI、ZR收录期刊

蔬菜对土壤PCNB-Cd复合污染富集效应的种间差异研究

PCNB and Cd Accumulations in Vegetables Grown on Contaminated Soil

  • 摘要:
    目的 不同蔬菜品种在五氯硝基苯(PCNB)和镉(Cd)复合污染环境中的富集能力差异显著。为探讨这一现象并为受污染农田的合理利用提供依据,本研究选取了几种常见蔬菜,分析其在PCNB-Cd污染环境中的生长反应及污染物富集能力。
    方法 通过盆栽试验,考察了生菜(Lactuca sativa)、油麦菜(Lactuca sativa var. longifolia)、小白菜(Brassica rapa subsp. chinensis)、萝卜(Raphanus sativus)和莴笋(Lactuca sativa var. angustata)在PCNB和Cd复合污染条件下的生长状态,以及这几种蔬菜对污染物的吸收及富集表现。
    结果 中、低浓度五氯硝基苯污染土壤(0.44~6.74 mg·kg−1)对叶菜类蔬菜生长有促进作用,高浓度(9.88~9.96 mg·kg−1)时则表现出抑制作用;而PCNB对根茎类蔬菜则为抑制作用;土壤镉污染(0.35~1.96 mg·kg−1)对5种蔬菜的生长也表现为抑制作用。PCNB-Cd污染土壤(PCNB: 0.47~9.88 mg·kg−1; Cd: 0.46~1.63 mg·kg−1)抑制了PCNB和Cd对蔬菜生长的影响。在高PCNB污染水平上,生菜、油麦菜、小白菜、莴笋的叶组织对PCNB的富集量均超过国家食品安全限量标准,而萝卜的块茎、莴笋的茎组织中PCNB的富集量均未超标。5种蔬菜都受到了Cd污染,莴笋叶片中的Cd含量超标最为严重,超过安全标准60倍,其次是莴笋茎部和萝卜。不同蔬菜对PCNB的富集能力从高到低依次为莴笋叶、小白菜、莴笋茎、油麦菜、生菜和萝卜;对Cd的富集表现为莴笋叶片最高,而油麦菜最低,差异显著(P<0.05, n=5)。
    结论 PCNB-Cd复合污染对蔬菜吸收PCNB、Cd无促进作用。综上,生菜、油麦菜PCNB、Cd的富集能力较低,适宜在轻度污染的PCNB-Cd复合污染土壤中种植。本研究的结果为成都平原地区蔬菜种植结构的优化调整提供了理论支持。

     

    Abstract:
    Objective Variations in accumulating PCNB and Cd of different species of vegetables grown on a contaminated soil were studied.
    Method  In a pot experiment, growth and pollutant absorption/accumulation of Lactuca sativa (CL), L. sativa var. longifolia (RL), Brassica rapa subsp.chinensis (PC), Raphanus sativus (RR), and L. sativa var. angustata (AL) on a PCNB-Cd contaminated soil was monitored.
    Result Light and medium levels (i.e., 0.44-6.74 mg·kg-1) of PCNB pollution on the soil stimulated growth of the leafy vegetables tested. However, when the contamination reached the severe level at 9.88-9.96 mg·kg-1, the growth was significantly inhibited. And all levels of the contamination were detrimental to growth of the root vegetables. Cd pollution at between 0.35 mg·kg-1 and 1.96 mg·kg-1 cut the biomass production on all 5 vegetables. In combination, PCNB at 0.47-9.88 mg·kg-1 and Cd at 0.46-1.63mg·kg-1 resulted in varied effects on the vegetable growth. The PCNB contents in the leaves of CL, RL, PC, and AL grown on the severely contaminated soil exceeded the food safety threshold, but the roots of RR and stems of AL did not. Meanwhile, Cd in AL leaves significantly rose to a level surpassing the standard by 60 times, which was followed by the level in the stems of AL and that in the roots of RR. Overall, PCNB absorbed by the vegetables or part of the plants ranked as AL leaves>PC>AL stems>RL>CL>RR, and Cd in the order of AL leaves> AL stems>RR PC>CL>RL (P<0.05, n=5).
    Conclusion The soil contaminated with PCNB-Cd did not significantly affect the absorption of the pollutants individually by the vegetables. In general, L. sativa and L. sativa var. longifolia accumulated PCNB and Cd less than the other tested vegetables making them more suitable for farming on lands moderately polluted with PCNB-Cd.

     

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