铅高暴露地区人群膳食安全暴露评估

1、铅高暴露地区人群膳食安全暴露评估摘 要目的：考察某矿区居民饮用水及自种蔬菜粮食的铅含量，调查当地居民的膳食结构，计算由膳食和饮水途径的铅暴露量，为评估当地居民由膳食铅暴露带来的健康风险，查究导致当地儿童血铅水平超标的原因以及铅来源提供参考和依据。材料和方法：考虑到相对均匀分布，随机选取该矿区20户居民，取其饮用水样品61份（包括对照），自种蔬菜粮食样品166份以及菜地土壤样品50份，用火焰或石墨炉原子吸收法测定样品中的Pb，样品预处理和分析过程均有严格的质量控制，所测标准物质结果均较好地符合标准值。每户选成年女性1名作为饮水量和膳食调查的对象。以样品中的铅含量和膳食调查的数据，计算风险指数，得

2、出当地居民的膳食由于Pb暴露而产生的风险水平。结果：（1）土壤铅含量未显示超标。（2）三个季节饮用水铅含量平均值为18.29±10.83g/L、42.74±36.36g/L和30.33±16.75g/L，分别是对照（2.99±1.13g/d、100.00g/d和63.60g/d，为对照（5.981.41±0.22 mg/kg（黄瓜）5.47±0.71 mg/kg（小白菜），铅含量全部超标。不同蔬菜种类对Pb的富集能力不同，富集系数大小依次为小白菜、葱、南瓜、韭菜、萝卜、白菜、茄子、黄瓜。三次采样居民每日经膳食途径的铅暴露量分别为730

3、g/d、995g/d、1790g/d。（4）该地区居民的平均每周单位体重的膳食Pb暴露量（膳食途径与饮水途径）为144g/kgbw/week，为Pb的PTWI值（25g/kgbw/week）的5.8倍。计算风险指数为5.77。结论：（1）该矿区居民饮用水以及自种蔬菜粮食中Pb含量较高，通过膳食和饮水途径摄入的铅较多，仅该途径的铅暴露量就大大超过了可接受的风险水平，有发生潜在健康危害的风险。必须采取有效措施降低膳食和饮用水Pb污染水平或切断暴露途径，以便减少产生健康危害的风险。（2）膳食途径和饮水途径中的Pb可能是当地儿童出现血铅超标和铅中毒症状的主要原因。关键词：食品安全；铅；暴露评估；可接受

4、风险AN EXPOSURE ASSESSMENT OF LEAD VIA DIET UPON LOCAL RESIDENTS IN A MINING AREAABSTRACTObjective：Through analyzing lead content in drinking water and vegetables of local residents in a certain mining area, investigating the dietary structure and calculating the lead exposure to the residents via loc

5、al diet, the health risk of lead exposure was assessed and scientific clues for locating the main reason of the lead pollution on local children and source of lead were presented.Materials and Methods: 20 female families in the area were randomly selected to collect samples. Corresponding samples in

6、clude 61 samples of drinking water, 166 samples of vegetables and cereals and 50 samples of soil. Flame-AAS and GF-AAS were used to analyze the lead content in samples. Sample preparation and analyzing process were carried out strict quality control measures to make sure the authenticity and accurac

7、y of the results. Housewives of the chosen families were selected as interviewers to undertake the dietary survey. The index of risk was calculated by combining data of lead content in samples and dietary survey to indicate that whether or not the risk level of lead exposure is acceptable.Results: (

8、1)The average level of lead content in the soil is not beyond the safe limit, (2)The average level of lead content in the water in three different sampling time was 18.29±10.83g/L, 42.74±36.36g/L and 30.33±16.75g/L. They are 6.12、14.29 and 10.14 times of the control(2.99±1.13g/L)

9、 respectively. Significantly variation among water lead content sampled in Nov.2004 and April.2005 was observed（P<0.01）.The average daily lead exposure in three sampling time via water was 32.36g/d, 100.00g/d and 63.60g/d. They are 5.41,16.72 and 10.64 times of the control(5.98g/d) respectively.

10、(3)The lead content in all vegetable samples were beyond the safe limit with range of 1.41±0.22 mg/kg(cucumber)5.47±0.71mg/kg(green chinese cabbage). Different varieties of vegetables and cereals have different bioconcentration factors(BCF) with following sequence: green chinese cabbagesha

11、llotcornpumpkinfoxtail milletleekradishcabbageeggplantcucumber. The average daily lead exposure in three sampling time via local diet was 730g/d、995g/d、1790g/d. (4)The average weekly lead exposure of local residents per body weight was 144g/kg bw/week, which is 5.8 times of PTWI for lead(25g/kg bw/w

12、eek). The index of risk was 5.77.Conclusion: (1)The lead content in the local drinking water, vegetables and cereals, and lead exposure to residents via diet were remarkably high in this mining area. Unacceptable risk toward the local residents occurred because of the lead exposure via the diet route. Measures should be taken to control the risk of food safety. (2)It can be infe