姜湖贡米产地土壤-作物系统重金属元素分布、累积特征

Distribution and accumulation of heavy metal elements in soil-crop system of Jianghugongmi producing area in Linyi,south of Shandong province

姜湖贡米是山东省名优特及国家地理标志农产品,通过全面采集该区土壤-作物系统样品,研究Pb、Cd、Hg、As元素在土壤-作物系统中的分布及累积特征。发现:①表层土壤及根系土、籽粒中重金属元素含量均低于相应限量标准值,土壤生态环境及食品安全风险低;②根系土相对表层土壤重金属元素发生了一定的富集,根系土重金属富集因子表明,As、Pb与自然成土过程有关,Hg、Cd可能受到人为来源影响;③水稻和小麦籽粒中重金属生物富集系数存在Cd>Hg>As>Pb的规律,茎叶中存在Cd>Hg>As、Pb的规律,表明水稻和小麦对Cd、Hg的累积程度高于As、Pb;④土壤-作物系统重金属元素富集系数由根系土-茎叶-籽实递减,Pb、As、Hg的分异明显,而Cd在水稻和小麦不同部分间生物富集系数波动较大。此外,水稻和小麦重金属富集系数与部分根系土组份的相关性表明,土壤肥力的提升可能会促进水稻和小麦对重金属的吸收。

Jianghugongmi is a famous,special and national geographical indication agricultural product of Shandong province.Based on soil-crop sampling systematically from Jianghugongmi producing area,the distribution and accumulation characteristics of Pb,Cd,Hg,and As in different soil crop systems were studied.The results showed that:(1)the contents of heavy metals in the top soil,root soil and grains were lower than the corresponding limit values,and the risk of soil ecological environment and food safety was low;(2)the heavy metals in the root soil were enriched relatively to the top soil,and its accumulation factors in the root soil showed that As and Pb were related to the natural soil formation process,and Hg and Cd might be affected by human sources;(3)the BCF of heavy metals in wheat and rice grain was Cd>Hg>As>Pb,and that in stem and leaf was Cd>Hg>As and Pb,which showed that the accumulation of Cd and Hg in wheat and rice is higher than that of As and Pb;and(4)the BCFs of heavy metal elements in soil-crop system decreased from root soil,stem and leaf to grains,and the differential characteristics of Pb,As and Hg were significant,while Cd BCF fluctuated greatly among different parts of wheat and rice.In addition,the correlation between the BCFs of heavy metal and some components of root soil showed that the increase of soil fertility might promote the uptake of heavy metals by wheat and rice.