摘要:
分析重金属在“环境-牛肝菌-人体”系统中的迁移、富集规律，为牛肝菌重金属污染防治及食用安全评价提供依据。采用ICP-AES法测定云南野生牛肝菌及其生长土壤中Cd和Hg含量，分析牛肝菌对重金属的富集特征及牛肝菌的重金属含量与土壤的联系，推测云南野生牛肝菌中重金属Cd和Hg的来源；根据FAO/WHO规定的每周Cd或Hg的允许摄入量(provisional tolerable weekly intake,PTWI)评估牛肝菌的重金属暴露风险。结果显示，(1)不同种类、产地牛肝菌中Hg和Cd含量具有差异，菌盖中Hg、Cd的含量分别在0.92~16.00 mg·kg-1 dw，4.97~24.07 mg·kg-1 dw之间，菌柄的Hg、Cd含量分别介于0.46~8.2 mg·kg-1 dw和2.11~22.08 mg·kg-1 dw之间。同一种牛肝菌菌盖中Hg或Cd的含量均高于菌柄(Q(C/S)＞1)，表明牛肝菌菌盖对Hg和Cd的富集能力强于菌柄。(2)牛肝菌菌盖和菌柄对Hg的富集系数(bioaccumulation factor,BCF)分别在1.72~19.12和1.30~6.40之间，菌盖、菌柄的Hg含量均高于相应生长土壤的含量，其中采自楚雄永仁县的铜色牛肝菌菌盖的Hg含量是土壤的19.12倍，表明牛肝菌中的Hg不仅来自土壤，根据山地“Hg诱捕效应”及云南大气Hg升高的相关报道，可以推测云南野生牛肝菌中的Hg主要来源于大气沉降。(3)牛肝菌菌盖、菌柄对Cd的富集系数分别在0.16~1.82和0.07~1.67之间，多数牛肝菌的Cd含量低于土壤含量，表明牛肝菌中的Cd主要来自生长土壤。(4)假设成年人(60 kg)毎周食用300 g新鲜牛肝菌则多数牛肝菌菌盖、菌柄的Hg摄入量低于PTWI(Hg)标准，Hg的暴露风险较低(假设未通过其他途径摄入Hg)；食用300 g黑粉孢牛肝菌菌盖或菌柄摄入的Cd达到0.722 mg和0.662 mg，超过PTWI(Cd)标准，食用有Cd暴露风险。
关键词:
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重金属
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汞
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镉
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野生牛肝菌
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食用菌
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富集系数
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健康风险
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云南
Abstract:
This study investigated the transfer and accumulation of heavy metal in the environment-boletes-humansystem. The content of mercury (Hg) and cadmium (Cd) in boletes and the topsoil was determined by ICP-AES. The accumulation characteristics of heavy metal in bolete mushrooms were observed and the relationship of heavy metal contents in boletes with that in the topsoil are studied. Then the source of heavy metal Hg and Cd in boletes were analyzed. The heavy metal exposure risk via the bolete mushrooms was assessed according to the Hg or Cd Provisionally Tolerable Weekly Intake (PTWI) recommended by the United Nations Food and Agriculture Organization and the World Health Organization (FAO/WHO). The results showed that (1) There were differences in Hg and Cd contents in different species of mushroom from different origins, and the Hg and Cd content in caps were in the range of 0.92-16.00 and 4.97-24.07 mg·kg-1 dw, and 0.46-8.2, 2.11-22.08 mg·kg-1 dw in stipes. The Hg and Cd contents in caps were higher than that in stipes in the same bolete species and the Q(C/S) values were greater than 1. It is demonstrated that the accumulation ability of Hg and Cd in caps was stronger than that in stipes in bolete mushrooms. (2) The Hg bioaccumulation factor in caps and stipes of different boletes were in the range of 1.72-19.12 and 1.30-6.40, respectively. The Hg contents in caps and stipes were higher than the topsoil.The Hg content in caps of Boletus aereus which collected from Yongren, Chuxiong was 19.12 times higher than the topsoil, indicating that the soil was not the only source of mercury in boletes. According to the reports of "Mountain Trapping Effect of Mercury" and the reasons for the rise of the Hg content in Yunnan, it can be speculated that the Hg in Yunnan wild boletes mainly comes from atmospheric deposition. (3) The Cd bioaccumulation factor in caps and stipes of different boletes were in the range of 0.16-1.82 and 0.07-1.67, respectively.The Cd contents in most of boletes were below the topsoil, indicating that boletes Cd mainly from the soil. (4) If the adults (60 kg) take 300 g fresh bolete mushrooms a week, Hg intakes of most samples were below the acceptable intake without health risk (assuming no Hg intake by other ways). However, under the same condition, the Cd intakes from caps and stipes of Tylopinus nigerrimus were 0.722 mg and 0.662 mg, which are higher than the the acceptable intake without health risk.
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