京郊蔬菜重金属含量特征及安全评价

Concentration analysis and health risk assessment of heavy metals in vegetables of Beijing suburban

采用原子吸收光谱法测定北京市10个郊区县25种蔬菜154个样品中Cr,Cd,Cu和Zn重金属含量,并与中国食品中污染物限量标准进行比较;运用目标危害系数方法 (the target hazard quotient,THQ)评价当地居民摄食蔬菜导致的健康风险,比较成人和儿童居民THQ值大小。结果显示,蔬菜中Cr,Cd,Cu和Zn的平均含量分别是0.210,0.0123,1.034,3.343mg/kg,均未超过中国食品中污染物限量标准,但根茎类蔬菜Cr含量均值超过限量标准,在根菜类中其超标率为41.2%;部分生菜样品的Cr含量有超标,在叶菜类蔬菜中的超标率为2.22%;蔬菜重金属综合污染指数的评价结果属于优良,在安全级别之列,其中Cr为轻污染,Cd,Cu和Zn为优良。成人摄食蔬菜导致的Cr,Cd,Cu和Zn的THQ值分别为1.134,0.199,0.419和0.181,儿童为1.490,0.262,0.550和0.237,两者均存在因摄食蔬菜导致的Cr潜在健康风险。成人和儿童重金属复合风险系数分别为1.932和2.539,复合风险主要由Cr引起。各单一重金属的复合风险对成人和对儿童贡献率基本上一致,儿童因为摄取蔬菜而引起的重金属健康风险相对大于成人。

In order to assess human health risk posed by elevated concentrations of heavy metals including chromium, cadmium, copper and zinc in vegetables, a survey of heavy metals levels in vegetables planted in suburban areas of Beijing was conducted. 154 fresh vegetable samples were obtained. The heavy metals contents of Cr, Cd, Cu and Zn in vegetables were measured using atomic absorption spectrometer （AAS）. The results were compared with main vegetable standards of China. Possible health risks to local residents caused by the heavy metals through consumption of vegetables were assessed based on target hazard quotient （THQ）, and THQ values between adults and children were compared. Results showed that the average contents of Cr, Cd, Cu and Zn in vegetables were 0. 210mg/kg, 0. 0123mg/kg, 1. 034mg/kg and 3. 343mg/kg, in which the four heavy metals were all in line with Chinese national food safety standards, while Cr content in part of root vegetables exceeded. THQs of Cr, Cd, Cu and Zn for adults due to consumption of vegetables were 1. 123, 0. 199, 0. 419 and 0. 181, while for children were 1. 490, 0. 262, 0. 550 and 0. 237, and both of which had potential health risks from Cr. Total metal THQs for adults and children were 1. 932 and 2. 539, which were mainly caused by Cr. Single heavy metal contribution rate to the combined risk was basical- ly the same for adults and children, but health risks for children caused by heavy metals were bigger than adults.