The contents of lead(Pb) in the soil,bark,leaf,walnut peel,shell,and kernel in Panxi region′s walnut were determined by using the atomic absorption spectrometry to study the accumulation characteristics and consumption risk.The results showed that the contents of Pb in the soil were significantly higher than those in the organs of the walnut tree,and one of the soil samples was exceed the national standard;the contents of Pb in the leaves were significantly higher than those in the walnut peel,shell,and kernel;with the increase of Pb content in the soil,the Pb contents in bark,leaf,walnut peel,shell,and kernel didn′t show an obvious enrichment regularity,and the accumulation ability of Pb in the walnut kernel was weaker compared with the other main organs.The results of the Nemerow Index Method showed that the pollution index of Pb in the walnut kernel was less than 1,which indicated that the kernel samples of the experimental point in Panxi production base were out of Pb pollution.Referring to China′s current standards,the target risk factor of Pb in the walnut was figured out by extending the tree nuts consumption of Chinese residents to the recommended value and much lower than 1.0, which meant the content of heavy metal Pb in the edible parts of walnut was temporarily risk-free for Chinese consumers′ health.%采用原子吸收光谱法测定攀西地区核桃产地9个试验点的土壤、树皮、叶、青皮、壳和仁中铅(Pb)的含量,分析了攀西地区核桃中Pb的积累特性及食用风险.结果表明:产地土壤中含Pb量显著高于核桃树各组织部位中的含Pb量,且有1个试验点的土壤含Pb量超标;各点核桃叶样品含Pb量均显著高于核桃青皮、壳和仁样品;随着土壤中含Pb量的增加,核桃树皮、叶、青皮、壳和仁无明显富集规律,与核桃其他主要组织部位相比,核桃可食用部分(核桃仁)富集Pb的能力较弱.内梅罗指数评价方法结果显示,核桃仁中Pb的污染指数P′值均<1,表明攀西核桃基地试验点的核桃仁样品均未受Pb污染.参照中国现行标准,结合我国居民树坚果的消费量,将其扩大化至推荐值,计算发现无论是对成人还是儿童,核桃仁中Pb的目标风险系数(THQ)都远低于1.0,说明核桃仁中重金属Pb含量对我国消费者的健康暂时是风险极低的.
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