title: Thallium dispersal and contamination in surface sediments from South China and its source identification.
abstract: Thallium (Tl) is a non-essential element in humans and it is considered to be highly toxic. In this study, the contents, sources, and dispersal of Tl were investigated in surface sediments from a riverine system (the western Pearl River Basin, China), whose catchment has been contaminated by mining and roasting of Tl-bearing pyrite ores. The isotopic composition of Pb and total contents of Tl and other relevant metals (Pb, Zn, Cd, Co, and Ni) were measured in the pyrite ores, mining and roasting wastes, and the river sediments. Widespread contamination of Tl was observed in the sediments across the river, with the highest concentration of Tl (17.3 mg/kg) measured 4 km downstream from the pyrite industrial site. Application of a modified Institute for Reference Materials and Measurement (IRMM) sequential extraction scheme in representative sediments unveiled that 60-90% of Tl and Pb were present in the residual fraction of the sediments. The sediments contained generally lower (206)Pb/(207)Pb and higher (208)Pb/(206)Pb ratios compared with the natural Pb isotope signature (1.2008 and 2.0766 for (206)Pb/(207)Pb and (208)Pb/(206)Pb, respectively). These results suggested that a significant fraction of non-indigenous Pb could be attributed to the mining and roasting activities of pyrite ores, with low (206)Pb/(207)Pb (1.1539) and high (208)Pb/(206)Pb (2.1263). Results also showed that approximately 6-88% of Tl contamination in the sediments originated from the pyrite mining and roasting activities. This study highlights that Pb isotopic compositions could be used for quantitatively fingerprinting the sources of Tl contamination in sediments.
authors.affiliation: Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China. Electronic address: liujuan858585@163.com.
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.affiliation: Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China. Electronic address: chenyong_heng@163.com.
authors.forename: Yongheng
authors.initials: Y
authors.lastname: Chen
authors.affiliation: High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Chuan-Chou
authors.initials: CC
authors.lastname: Shen
authors.affiliation: Key Laboratory of Humid Subtropical Eco-geographical Processes, Ministry of Education, College of Geography Science, Fujian Normal University, Fuzhou 350007, China.
authors.forename: Xiuyang
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Xie
authors.affiliation: Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.
authors.forename: Diyun
authors.initials: D
authors.lastname: Chen
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Institut für Ressourcenökologie Forschungsstelle Leipzig, Leipzig 04318, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Lippold
authors.affiliation: Guangdong Provincial Academy of Environmental Science, Guangzhou, 510045, China.
authors.forename: Chunlin
authors.initials: C
authors.lastname: Wang
mesh_terms: D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D006801:Humans; D007501:Iron; D007554:Isotopes / Q000032:analysis; D007854:Lead / Q000032:analysis; D008670:Metals / Q000032:analysis; D008906:Mining; D045483:Rivers; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D013440:Sulfides; D013793:Thallium / Q000032:analysis*
chemical_list: D007554:Isotopes; D008670:Metals; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides; C011342:pyrite; D007854:Lead; D013793:Thallium; D007501:Iron
keywords: Binary model; Pb isotope; Pyrite; Tl contamination