Yang Chunxia, Chen Yongheng, Peng Ping'an, Li Chao, Chang Xiangyang, Xie Changsheng
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China.
Sci Total Environ. 2005 Apr 1;341(1-3):159-72. doi: 10.1016/j.scitotenv.2004.09.024.
The total concentrations combined with the chemical speciation of thallium (Tl) were examined in order to track the distribution of natural and anthropogenic Tl in the soils in an industrial pyrite slag disposing area. Their geochemical behaviors in the soils were further discussed. Soil samples were collected from three soil profiles adjacent to a large open-disposed pile of industrial Tl-rich pyrite slag, and from one soil profile in the background area. The results show that the soil contamination with Tl derived from slag (slag-Tl) is generally limited; slag-Tl was mainly accumulated in the upper part (< 16.5 cm) of the vicinal soils of the slag pile and shows large variation in concentration among different sampling sites. Basically, the soils surrounding the slag pile within 5 m are more Tl-contaminated than those under the slag pile and those far away from the slag pile. In respect of the concentrations of total Tl, the deeper soils of the studied profiles seem to be uncontaminated. However, the percentages of Tl in the easily reducible fraction indicate that these soils have been actually contaminated by slag-Tl. Natural Tl and anthropogenic Tl are distributed differently among the soil components in the studied soils. Natural Tl in the background soils is predominantly hosted in the residual fraction ( approximately 98%), while anthropogenic Tl was significantly incorporated into the more labile fractions of the soil (up to approximately 80%), especially in the acid-extractable fractions and easily reducible fraction (up to approximately 30% and approximately 45%, respectively). Detailed analysis of speciation data of Tl suggests that despite being predominantly controlled by the degree of Tl pollution, the distribution of slag-Tl in the soils can be further affected by the general differences in soil properties. In this study, the order for preferential immobilization of anthropogenic Tl among major soil components can be roughly summarized as: Tl(III) carbonates and hydroxides > Mn oxide-hydroxides > Fe oxide-hydroxides > adsorption sites on the surface of soil, while the order can be significantly mediated by the pH conditions in the soils. The correlations between the fractions of Tl in the slag and in the soils indicate that the anthropogenic Tl in the soils in the studied slag disposing area should be mainly derived from the dissolved slag-Tl that was leached by rainwater rather than from the washed-out particles of slag.
为追踪工业硫铁矿渣处置区土壤中天然铊（Tl）和人为源铊的分布情况，对铊的总浓度及其化学形态进行了研究，并进一步探讨了其在土壤中的地球化学行为。从靠近一个大型露天堆放的富铊工业硫铁矿渣堆的三个土壤剖面以及背景区域的一个土壤剖面采集了土壤样本。结果表明，来自矿渣的铊（矿渣铊）对土壤的污染总体有限；矿渣铊主要累积在矿渣堆附近土壤的上部（<16.5厘米），且不同采样点的浓度差异较大。基本上，矿渣堆周围5米范围内的土壤比矿渣堆下方和远离矿渣堆的土壤受铊污染更严重。就总铊浓度而言，所研究剖面较深的土壤似乎未受污染。然而，易还原态铊的百分比表明这些土壤实际上已受到矿渣铊的污染。在所研究的土壤中，天然铊和人为源铊在土壤组分中的分布不同。背景土壤中的天然铊主要存在于残余态（约98%），而人为源铊则显著地进入了土壤中更不稳定的形态（高达约80%），特别是酸可提取态和易还原态（分别高达约30%和约45%）。铊形态数据的详细分析表明，尽管矿渣铊在土壤中的分布主要受铊污染程度控制，但土壤性质的总体差异会进一步影响其分布。在本研究中，主要土壤组分对人为源铊优先固定的顺序大致可概括为：Tl(III)碳酸盐和氢氧化物>锰氧化物氢氧化物>铁氧化物氢氧化物>土壤表面吸附位点，而该顺序会受到土壤pH条件的显著影响。矿渣和土壤中铊各形态之间的相关性表明，所研究的矿渣处置区土壤中的人为源铊应主要来自雨水淋滤出的溶解态矿渣铊，而非矿渣的冲刷颗粒。
