State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
Sci Total Environ. 2013 Apr 15;450-451:140-7. doi: 10.1016/j.scitotenv.2013.02.008. Epub 2013 Mar 6.
Thallium (Tl) is a non-essential and toxic trace metal found in many plants, but it can accumulate at particularly high concentration in green cabbage (Brassica oleracea L. var. capitata L.). The aim of this study is to explore the transfer and accumulation of Tl at the interface of rhizospheric soil and green cabbage from a long-term Tl contaminated site in southwestern Guizhou Province, China. Influencing factors such as Tl distribution in various soil fractions and physical-chemical characteristics of rhizospheric soil were also investigated. Our results demonstrated that green cabbage had high accumulation of Tl, with most bioconcentration factor (BF) values exceeding 1, and up to a maximum level of 11. The enrichment of Tl in the green cabbage tissues followed a descending order, i.e. old leaves>fresh leaves>stems≈roots. The stems functioned as a channel for Tl transportation to the leaves, where most of the Tl (greater than 80%) was found to accumulate. In the rhizospheric soils, 62-95% of Tl existed in the residual fraction, while lower concentrations of Tl (on average, 1.7% of total T1 in rhizospheric soil) were found in the water and acid soluble fractions. The major fraction of labile Tl was located in the reducible fraction (9%). Our results also suggested that the uptake and enrichment of Tl in green cabbage were affected by Tl concentrations, soil water content, soil pH, soil organic material (SOM) and cation exchange capacity (CEC) in rhizospheric soil.
铊（Tl）是一种非必需的有毒痕量金属，存在于许多植物中，但它可以在甘蓝（ Brassica oleracea L. var. capitata L.）中特别高浓度地积累。本研究旨在从中国贵州省西南部一个长期铊污染的地点，探索根际土壤和甘蓝之间铊的迁移和积累。还研究了影响因素，如各种土壤部分中的 Tl 分布和根际土壤的物理化学特性。我们的结果表明，甘蓝对 Tl 具有高积累性，大多数生物浓缩因子（BF）值超过 1，最高可达 11。Tl 在甘蓝组织中的富集遵循一个递减的顺序，即老叶>新叶>茎≈根。茎作为 Tl 向叶片运输的通道，大部分 Tl（大于 80%）都在叶片中积累。在根际土壤中，62-95%的 Tl 存在于残渣部分，而水溶性和酸溶性部分的 Tl 浓度较低（平均占根际土壤中总 T1 的 1.7%）。可利用 Tl 的主要部分位于可还原部分（9%）。我们的结果还表明，甘蓝对 Tl 的吸收和富集受到 Tl 浓度、土壤含水量、土壤 pH 值、土壤有机物质（SOM）和根际土壤阳离子交换容量（CEC）的影响。
