随着科技的发展,化学物质被广泛使用,重金属对蔬菜的污染与日俱增.为研究重庆城区市售蔬菜的重金属含量特征,在重庆市主城区多个农贸市场随机采集8类37种蔬菜,采用原子吸收光谱法测定其重金属Cd、Ni、Cr和Pb的含量并进行污染评价及健康风险评估,以期为重庆市的蔬菜安全生产提供参考依据和数据支撑.结果表明,蔬菜样品中Ni、Cr、Cd和Pb的平均质量分数分别为383.9 、171.4、15.1和192.1 μg·kg-1;其超标率分别为12.6%、3.9%、2.4%和51.2%,Pb超标率较严重.根据单项污染指数,蔬菜中Cd和Cr为优良状态,Ni为安全状态,而蔬菜受Pb污染的问题较为突出;其中,茎类蔬菜受到的 Pb 污染较为严重,属于中污染;块根类、鳞茎类、茄果类和瓜类蔬菜受 Pb 污染相对较轻,处于轻污染;芸薹类、豆类、叶菜类蔬菜均未受到Pb污染.通过目标危险系数(THQ)评价单一重金属产生的健康风险,结果表明,蔬菜中重金属Cd、Ni、Cr和Pb的THQ均表现为儿童>中老年>青壮年,4种重金属对儿童的危害较大.儿童、青壮年和中老年3类人群的总目标危险系数(TTHQ)分别为1.003、0.802和0.902,其中仅儿童的TTHQ大于1,说明儿童属于敏感人群,长期食用这些蔬菜可能带来较高的健康风险;中老年人群的TTHQ已接近风险值1,也应引起足够重视.%With the development of science and technology, heavy metal pollution to vegetables is increasing day by day, because of the widespread use of chemicals. To study the characteristics of heavy metals in vegetables sold in farmers' markets of Chongqing city, 37 vegetable samples in eight categories were randomly collected from several farm product markets in urban area of Chongqing. The concentration of Cd, Ni, Cr and Pb in vegetables was determined by atomic absorption spectrometry, and pollution assessment and health risk evaluation were carried out. The aim was to provide reference and data for vegetable safety production in Chongqing. The results showed that the average concentration of Ni, Cr, Cd and Pb in vegetable samples was 383.9, 171.4, 15.1and 192.1 μg·kg-1, and their over standard rates were 12.6%, 3.9%, 2.4% and 51.2%, respectively. The rate of Pb exceeding the standard was the most serious. According to the pollution index, Cd and Cr in vegetables were in good state, Ni in vegetables was in safe state, while most vegetables were polluted by Pb. The pollution of stem vegetables caused by Pb was more serious, which belonged to moderate pollution. Heavy metal Pb in root, bulb, solanaceous fruit, and melon vegetables was slight pollution, while brassica, beans, leafy vegetables were not polluted by Pb. The target hazard quotient (THQ) was applied to evaluate the health risk produced by a single heavy metal. The results demonstrated that the THQ of Cd, Ni, Cr and Pb in the vegetables was in the following order:children>the middle aged>young adults, and these four heavy metals were more harmful to children. The total target hazard quotient (TTHQ) of three groups of children, young adults and the middle aged was 1.003, 0.802 and 0.902, respectively. Among them, the TTHQ>1 of children only showed that children belonged to the sensitive population. Long-term consumption of these vegetables might bring higher health risks. However, the TTHQ of the middle-aged was close to the risk value of 1, and should also be paid enough attention.
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