潘攀 刘贝贝 吴琳 符旖晴 武春媛 李勤奋 范成五

摘  要：建立土壤重金属安全阈值是保障我国农产品质量安全的一道重要屏障。本研究通过盆栽模拟实验研究香蕉对砷（As）、镉（Cd）、铅（Pb）3种重金属的富集转运特点，进一步通过建立香蕉茎叶与土壤As、Cd、Pb总量和有效态含量的关系，推导香蕉种植系统的土壤As、Cd、Pb的安全阈值。结果显示，Cd、Pb对香蕉生物量表现出“低促高抑”的作用。香蕉各组织对As的富集规律为：根>叶>茎;而对Cd、Pb的富集规律表现为：根>茎>叶。根茎向叶转运As的能力强于转运Cd和Pb。采用回归分析方法，建立香蕉茎叶中重金属与土壤重金属总量和有效态含量之间的回归模型共12个，根据GB 13078—2017《饲料卫生标准》中对原料As、Cd、Pb的限量规定推导出香蕉土壤中As、Cd、Pb总量安全阈值分别为102.40、0.46、15.39 mg/kg，有效态含量安全阈值分别为4.77、0.10、5.27 mg/kg。

关键词：香蕉;重金属;安全阈值;富集转运

中图分类号：S668.1; X26      文献标识码：A

Abstract： Heavy metal safety threshold is important for the control of the quality and safety of agricultural products. In this study， banana （Musa spp.） seedlings were planted in a pot experiment with soils contaminated by different concentrations of arsenic （As）， cadmium （Cd） and lead （Pb） to determine the accumulation and transformation characteristics of As， Cd and Pb by banana， and the heavy metal safety thresholds were calculated by the regression models between the concentrations of heavy metals in banana stems and soils. Low concentrations of Cd and Pb showed positive promoting effect on the growth of banana， while high concentrations of Cd and Pb inhibited the growth of banana. Accumulation of As in banana tissues decreased in the order of root > leaf > shoot， while the accumulation of Cd and Pb in banana tissues decreased in the order of root > shoot > leaf. The transportation of As from root and shoot to leaf was higher than Cd and Pb. Twelve regression models between the concentrations of heavy metals in banana stems and the concentrations of total and available heavy metals in soil were built. According to the criterion of Standard of Feed Hygiene （GB 13078—2017） in China， the safety threshold of heavy metals in banana planting soils was calculated as 102.40， 0.46 and 15.39 mg/kg respectively for total As， Cd and Pb， and 4.77， 0.10， 5.27 mg/kg respectively for available As， Cd and Pb.

Keywords： banana （Musa spp.）; heavy metal; safety threshold; accumulation and transformation

DOI： 10.3969/j.issn.1000-2561.2021.01.036

近年來，土壤重金属污染问题受到了极大的关注。2014年的《全国土壤污染状况调查公报》[1]，报道了我国耕地土壤污染超标率达19.4%，其中以砷（As）、镉（Cd）、铅（Pb）无机物为主。耕地土壤环境中的重金属污染不仅会影响农作物的产量和品质，更可能通过食物链危害人体健康[2]。2019年1月1日正式实施的《中华人共和国土壤污染防治法》明确规定了实施农产品质量安全风险管控、保障农业生产环境安全等制度。而建立土壤重金属安全阈值是保障我国农产品质量安全的一道重要屏障，根据土壤重金属安全阈值，合理布局种植区域能够确保食品安全。