典型设施蔬菜基地重金属的累积特征及风险评估

【目的】以北京市设施蔬菜基地为例,研究重金属的累积特征及其健康风险,明确不同重金属在土壤-蔬菜系统中的迁移特征,为蔬菜质量安全和设施蔬菜结构优化提供参考依据。【方法】采集北京市9个典型设施蔬菜基地的148个土壤和96个蔬菜样品,分析土壤和蔬菜样品中As、Cd、Cr、Hg和Pb 5种重金属的统计特征及在土壤-蔬菜系统中迁移系数,并结合美国环保署(US EPA)推荐采用的健康风险评价模型,评价由于蔬菜摄入导致的成人和儿童的健康风险。【结果】设施蔬菜基地土壤中As、Cd、Cr、Hg和Pb的平均含量分别为9.43、0.18、64.4、0.11和21.6 mg·kg-1。设施蔬菜基地蔬菜中As、Cd、Cr、Hg和Pb的平均含量分别为0.0478、0.0391、0.2785、0.0014和0.0454 mg·kg-1。总体上,蔬菜设施基地5种重金属在土壤-蔬菜中迁移能力顺序为:CdHgCrAsPb。5种重金属造成的目标危害系数大小依次为:CdPbHgAsCr。所有蔬菜样品中单一重金属的目标危害系数均小于1,表明单一重金属没有明显的负面影响。【结论】本研究所选设施蔬菜基地的土壤重金属(As、Cd、Cr和Hg)存在积累趋势,须重视健康风险。

Accumulation Characteristics and Risk Assessment of Heavy Metals in Typical Greenhouse Vegetable Bases

【Objective】The objective of this paper is to study accumulation characteristics and health risk of heavy metals in greenhouse vegetable base of Beijing, to determine the migration rule of heavy metals from soil to vegetable, and to provide reference basis for vegetable quality safety and optimization of vegetable structure in Beijing. 【Method】 148 soil samples and 96 vegetable samples were collected from 9 typical greenhouse vegetable bases in Beijing, the statistical characteristics of As, Cd, Cr, Hg and Pb in soil and vegetable samples and their transfer factors from soil to vegetable system were analyzed. Combined with the EPA (US) recommended health risk assessment model, the health risks of adults and children as a result of vegetable intake were evaluated. 【Result】 The mean concentrations of As, Cd, Cr, Hg and Pb in soils were 9.43, 0.18, 64.4, 0.11 and 21.6 mg·kg^-1, respectively. The mean concentrations of As, Cd, Cr, Hg and Pb in vegetables were 0.0478, 0.0391, 0.2785, 0.0014 and 0.0454 mg·kg^-1, respectively. On the whole, the migration ability of heavy metals in greenhouse vegetable bases were decreased in the order of Cd＞Hg＞Cr＞As＞Pb. Target hazard quotients caused by heavy metals were decreased in the order of Cd＞Pb＞Hg＞As＞Cr. The target hazard quotient of single heavy metal in all vegetable samples was less than 1, which indicated that there was no obvious negative effect of single heavy metal. 【Conclusion】 The accumulation of heavy metals (As, Cd, Cr and Hg) in the soil samples from the greenhouse vegetable bases were found, health risks should be emphasized.