烟草对砷的吸收累积特征及其健康风险研究

以福建省主栽烟草品种翠碧1号、K326和云烟87为材料,在外源砷添加量为0、10、20、40、70和100 mg·kg~(-1)的土壤中进行盆栽试验,探讨砷对烟草的毒害效应以及砷在土壤-烟草体系中的迁移累积特征,并对植烟土壤中砷的安全临界值进行计算。结果表明,在砷毒害下,烟草生长受到抑制,且烟草根系生长受抑制程度最强。随着砷添加量的增加,土壤中有效砷含量和烟草各部位砷含量均显著提高(P 0.05),砷在根系中的含量最高,在茎中的含量最低。砷处理下各部位间的转移系数表现为TF_((茎-叶)) TF_((土-根)) TF_((根-茎)),且外源砷的增加促进砷从茎到叶片中转移。38.28%～74.37%的砷富集在烟草根部,上部叶中砷的富集量最少(4.61%～11.7%),且所研究的3个烟草品种中翠碧1号对砷的富集能力最强。根据通过吸烟进入人体砷的限量以及土壤有效砷含量与烟草中部叶砷含量的回归模型,推算出翠碧1号、K326和云烟87的植烟土壤有效砷的安全临界值分别为14.17、14.31和11.86 mg·kg~(-1)(磷酸二氢钠浸提)。并将福建省植烟土壤有效砷的安全临界值拟定为11.86 mg·kg~(-1)(磷酸二氢钠浸提)。本研究结果为福建省烟草安全生产提供一定技术指导。

Accumulation and Transfer of As in Tobacco Tissues and Its Health Risk to Human

The objective of this work is to enlighten the positive and negative effects of arsenic (As) in tobacco-growing soils. For this purpose three tobacco cultivars (Cuibi-1, K-326, and Yunyan-87) were grown in pots and the soil was treated with different amounts of As (0, 10, 20, 40, 70, and 100 mg kg^-1). The obtained results indicated that the growth of tobacco was inhibited due to serious effects on roots with the As treated soil. With the increasing amount of As in soil the accumulation in the tobacco tissues was also increased significantly (P<0.05). The transfer factors of As between different tobacco tissues were calculated and showed as: TF_(stem-leaf) > TF_(soil-root) > TF_(root-stem). The highest and lowest percentage of As accumulated in the root and in the upper leaf were 38.28%~74.37% and 4.61%~11.7%, respectively. Cuibi-1 cultivar showed higher As accumulation capacity than other two cultivars. We worked on the regression model between the content of As in tobacco middle leaves and in the soil, based on the limited content of As entering human body by smoking, and obtained the safety threshold level for tobacco cultivated soil. We determined that the safety threshold level for cultivated soils of Cuibi-1, K-326 and Yunyan-87 were 14.17, 14.31 and 11.86 mg kg^-1, respectively. The safe amount of As in tobacco cultivated soil according to our study should be 11.86 mg kg¹.