北京市菜地土壤和蔬菜铅含量及其健康风险评估

【目的】研究北京市菜地土壤和蔬菜铅含量及其健康风险，筛选出抗铅污染能力强的蔬菜品种，为北京市蔬菜食用安全性评估和种植结构优化提供参考依据。【方法】根据各品种蔬菜消费量优先和兼顾品种多样性的原则采集蔬菜样品，计算北京市居民蔬菜铅平均摄入量及其健康风险，利用蔬菜铅富集系数筛选抗铅污染品种。【结果】北京市菜地土壤铅含量范围、算术均值和几何均值分别为13.2～78.8、30.3和28.7 mg·kg-1，蔬菜铅含量范围、中值、算术均值和Box-Cox均值分别为0.1～654.5、51.3、80.9和48.7 μg·kg-1FW，基于《食品中铅限量卫生标准》的综合超标率为9.2%；北京市本地产和裸露地蔬菜铅浓度分别显著高于市售外地产蔬菜和设施栽培蔬菜；叶甜菜抗铅污染能力最强，其次是黄瓜、冬瓜、大白菜、茄子、大葱、西红柿和甘蓝，而云架豆、萝卜、辣椒和小白菜抗铅污染能力最差；北京市成人和儿童蔬菜铅人均每天的摄入量为16.6和13.6 μg。【结论】北京市菜地土壤铅积累明显，蔬菜铅对北京市居民（尤其是儿童）的健康存在较大威胁。

A Survey of Lead Concentrations in Vegetables and Soils in Beijing and their Health Risks

【Objective】 To assess the human health risk posed by elevated concentrations of lead in vegetables and to identify lead pollution-tolerant vegetable varieties. The results could be used to guide vegetable safety evaluation and vegetable optimize planting patterns. 【Method】A large scale survey of lead levels in soils and vegetables planted or sold in Beijing was conducted with giving priority to the consumption weight of vegetables and taking account of varieties. Lead health risk was accessed with lead intake from vegetable consumption, and lead pollution-tolerant vegetable varieties were identified with bioconcentration factors (BCFs). 【Result】Lead concentrations in soils ranged from 13.2 to 78.8 mg·kg-1, with arithmetic, median and geometric means of 30.3 and 28.7 mg·kg-1, respectively. Lead concentrations in the edible plant portions ranged from 0.1 to 654.5 μg·kg-1FW, with arithmetic, median and Box-Cox means of 80.9, 51.3 and 48.7 μg·kg-1FW, respectively. In 9.2% of the samples, lead was higher than the Tolerance Limit of Lead in Foods (TLCF) of 0.8 mg·kg-1 fresh weight for pulse and 0.2 mg·kg-1 for other vegetables. The lead concentration in vegetables from Beijing was significantly higher than that of vegetables imported from other places in China, and the lead in the field-grown vegetables was significantly higher than that of vegetables planted in a greenhouse. Results of hierarchical cluster analysis on the BCF of lead in vegetables indicated that the plants sampled could be separated into three groups based on BCF. Round beans trellis (Vigna unguiculata), radish (Raphanus), chili (Capsicum annuum) and bakchoi (Brassica chinensis), which constituted the first group, had the highest BCFs. The second group, which includes cucumber (Cucumis sativus), wax gourd (Beninacasa hispida), Chinese cabbage (Brassica pekinensis), eggplant (Solanum sp.), Chinese green onion, tomato (Lycopersicon esculentum) and cabbage (Brassica oleracea), had higher lead BCFs while leaf beet (Beta vulgaris) and some special varieties vegetables had lower lead BCFs. For adult and children in Beijing, the average ingestion rates of lead from vegetables were 16.6 and 13.6 μg·d-1, respectively. 【Conclusion】 Compared with the background lead concentrations of soil from Beijing, there appeared to be a significant accumulation of lead in soil collected from vegetables plot. Consuming vegetables with elevated lead concentrations may pose a health risk to local residents, particularly the children or ill.