北京市菜地土壤和蔬菜中铜含量及其健康风险

A Survey of Copper Concentrations in Vegetables and Soils in Beijing and Their Health Risk

根据蔬菜消费量和兼顾品种多样性的原则,在北京市规模化蔬菜栽培基地和蔬菜批发市场分别采集53个菜地土壤和100种蔬菜416个样品,以研究蔬菜和土壤铜含量及其健康风险,并评价不同蔬菜品种对土壤铜的富集能力。结果表明,与北京市土壤背景值相比,北京市菜地土壤铜积累明显,其含量范围、算术均值、中值、几何均值分别为6.0￣65.2、24.5、23.2和22.7 mg.kg-1,菜地土壤铜含量均低于《土壤环境质量标准》的蔬菜地土壤质量标准;北京市蔬菜铜含量符合对数正态分布,其含量范围、算术均值和几何均值分别为0.024￣8.25、0.713和0.505 mg.kg-1鲜重;瓜果类蔬菜铜含量显著高于叶菜类和根茎类蔬菜,特菜类铜含量显著高于叶菜类蔬菜。北京市裸露地蔬菜铜含量显著高于设施栽培蔬菜,但北京市本地产蔬菜和外地产蔬菜铜含量差异不显著。铜含量与对土壤铜的富集能力以云架豆为最高,因而其抗污染能力较差,茄子、辣椒、小白菜和大葱铜含量次之,冬瓜、黄瓜、大白菜、西红柿、甘蓝、萝卜、叶甜菜和部分特菜最低。估算表明,北京市居民从蔬菜中摄入铜的量为815.6μg.人-.1d-1,目前尚无明显的健康风险。

In order to assess the human health risk posed by elevated concentrations of copper in vegetables, and to identify pollution-tolerant vegetable varieties, a large scale survey of copper levels in soil and vegetables planted or sold in Beijing was conducted. 53 soil samples were collected from gardens and fields growing vegetables. 100 varieties of 416 fresh vegetable samples were obtained from vegetable stalls, supermarkets and wholesale outlets. Copper concentrations were measured using graphite furnace atomic absorption spectrometry （GF-AAS）. Copper concentrations in soils ranged from 6.0 to 65.2 mg· kg^-1, with arithmetic, median and geometric means of 24.5, 23.2 and 22.7 mg· kg^-1, respectively. Compared with the background copper concentrations of soil from Beijing, there seemed a significant accumulation of copper in soil collected from fields that produce vegetables. Copper concentrations in the edible plant portions was 0.024-8.25 mg· kg^-1 fresh weight, with arithmetic and geometrical means of 0.713 and 0.505 mg·kg^-1 fresh weight, respectively. In all of the samples and vegetable species, copper was less than the Tolerance Limit of Copper in Foods （TLCF） of 20 mg· kg^-1 fresh weight for pulse and 10 mg· kg^-1 for other vegetables. The highest copper level of 8.25 mg· kg^-1 was found in a sample of beans round trellis. The copper concentration in gourd and fruit vegetables was significantly higher than that of leaf vegetables and rootstalk vegetables. And the copper concentration in vegetables from field-grown vegetables was significantly higher than those planted in a greenhouse, but there was no significant difference between vegetables from other places of China input to Beijing and those of produced from Beijing. Hierarchical cluster analysis on the copper bioconcentration factor （BCF） in vegetables indicated that the plants sampled could be separated into three groups based on BCF. The first group, beans round trellis, had the highest BCF, and the following was the second group, including eggplant, chili, Pakchoi and Chinese green onion, while wax gourd, cucumber, Chinese cabbage, tomato, cabbage, radish and leaf beet had lower copper BCF. The average ingestion rate of copper from vegetables was 815.6 μg· d^-1 for individual people in Beijing, being 82.4% of the quantity demanded （990 μg· individual^-1· d^-1） and 6.8% of Provisional Maximum Tolerable Daily Intake （PMTDIs） （12 mg· individual^-1· d^-1）.Consuming vegetables with elevated copper concentrations may not pose a health risk to local residents.