Thallium geochemical fractionation and migration in Tl-As rich soils: The key controls

Xudong Wei, Jin Wang, Jingye She, Jing Sun, Juan Liu, Yuxuan Wang, Xiao Yang, Qi'’en Ouyang, Yuyang Lin, Tangfu Xiao, Daniel C.W. Tsang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Thallium (Tl) pollution caused by mining and processing of Tl-enriched ores has become an increasing concern. This study explored the geochemical fractionation and vertical transfer of Tl in a soil profile (200 cm) from a representative Tl-As mineralized area, Southwest China. The results showed that the soils were heavily enriched by Tl and As, with concentration ranging from 3.91–17.3 and 1830–8840 mg/kg (6.79 and 2973 mg/kg in average), respectively. Approximately 50% of Tl occurred in geochemically mobile fractions in the topsoil, wherein the reducible fraction was the most enriched fraction. Further characterization using LA-ICP-MS and TEM revealed that enriched Tl and As in soils were mainly inherited from the weathering of mine tailing piles upstream. XPS characterization indicated that Fe oxides herein may play a critical role in the oxidation of Tl(I) to Tl(III) which provoked further adsorption of Tl onto Fe oxides, thereby facilitating Tl enrichment in the reducible fraction. The findings highlight that the pivotal role of Fe oxides from mineralized area in the co-mobility and migration of Tl and As in the depth profile.

Original languageEnglish
Article number146995
JournalScience of the Total Environment
Volume784
DOIs
Publication statusPublished - 25 Aug 2021

Keywords

  • Geochemical fractionation
  • LA-ICP-MS
  • Metal/metalloid speciation
  • Mine tailings contamination
  • Tl-As in soil

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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