北京市菜地土壤和蔬菜铬含量及其健康风险评估

A survey of chromium concentrations in vegetables and soils in Beijing and the potential risks to human health

对北京市97种蔬菜的345个蔬菜样品和54个菜地土壤中的铬含量进行了研究．结果表明，北京市菜地土壤中铬含量的含量范围、算术均值、中值、几何均值分别为25．4—86．3、44．5、42．2、43．4mg·kg，均低于《土壤环境质量标准》中的蔬菜地土壤质量标准，但显著高于北京市土壤铬背景值．蔬菜铬的含量范围、算术均值和几何均值分别为0.4-1034、64．6、22．7μg·kg^-1．叶菜类和根茎类蔬菜的铬平均含量显著高于特菜类，其它类型的蔬菜铬含量差异不显著．北京市本地产蔬菜和裸露地蔬菜的铬含量均分别显著高于市售外地产蔬菜和设施栽培蔬菜．甘蓝的铬富集系数较高，小白菜、云架豆和冬瓜次之。而西红柿、黄瓜、大葱、叶甜菜、萝卜、大白菜、茄子和辣椒和部分特菜等铬富集系数最低．北京市居民从蔬菜中摄入铬的量为每人50．5μg·d^-1，目前已存在一定的潜在健康风险．

In order to assess the human health risk posed by elevated concentrations of chromium in vegetables, and to identify pollution-tolerant vegetable varieties, a large scale survey of chromium levels in soll and vegetables planted or sold in Beijing was conducted. Fifty-four soil samples were collected from gardens and fields used to grow vegetable plants. In addition, 97 varieties of 345 fresh vegetable samples were obtained from vegetable stalls, supermarkets and wholesale outlets. Chromium concentrations were measured using graphite furnace atomic absorption spectrometry （GF-AAS）. Chromium concentrations in soils ranged from 25. 4 to 86.3 mg· kg ^-1, with arithmetic, geometric and Box-Cox means of gg, 53. 43.45 and 42.25 mg· kg^-1. respectively. Compared with the background chromium concentrations of soil from Beijing, there appeared to be a significant accumulation of chromium in soil collected from fields that produce vegetables. Chromium concentrations in the edible plant portions ranged from 0. 4μg · kg^-1 fresh weight to 1039. 5μg· kg^-1 fresh weight, with arithmetic, geometric means of 64.6, 22.7 μg· kg^ -1 fresh weight, respectively. In 99.04% of the samples, chromium was lower than the Tolerance Limit of Chromium in Foods （TLCF） of 1.0mg·kg^-1 fresh weight for pulse and 0.5mg·kg^-1 for other vegetables. The TLCF is the maximum permissible concentration of chromium in vegetables that will be consumed by people, The highest level of chromium detected in a vegetable plant was 1039.5 μg·kg^-1, which was measured in a hot pepper （Capsicum annuum） sample. Chromium was detected at 1008.0 μg· kg^ -1 in kale （ Brassiea oleraeea） sample. 722.8 μg· kg^ -1 in Heiguo, 698.0 μg· kg^ -1 in a Chinese cabbage （ Brassica chinensis） sample,687.4 μg· kg^- 1 in wax gourd （Benincasa hispida） sample and 587.4 μg· kg^-1 hot pepper （Capsicum annuttm） sample. The chromium concentration in field-grown vegetables was significantly higher than the concentration of those planted in a greenhouse. And the chromium concentration in local vegetables was significantly higher than the concentration of those from other provinces of China. Results of hierarchical cluster analysis on the chromium bioconcentration factor （BCF） in vegetables indicated that the plants sampled could be separated into three groups based on BCF. Cabbage （ Brassica oleracea） had the highest BCF, following were Pakchoi （ Brassica chinensis ） , wax gourd （ Beninacasa hispida ） and beans round trellis （ Vigna unguiculata）, which had higher chromium BCFs while chili （Capsicum annuum）, eggplant （Solarium sp. ）, welsh onion （Allium fistulosum）, Beet （ Beta vulgaris）, Chinese cabbage （ Btassica pekinensis ） , radish （ Raphanus ） , cucumber （ Cucumis sativus ） , tomato （ Lycopersicon esculentum ） had lower chromium BCFs. The average ingestion rate of chromium from vegetables was 50.5 μg/individual/day for people of Beijing. Consuming vegetables with elevated chromium concentrations may pose a health risk to local residents, particular to the youth elder, or illness.