Historical roasting of thallium- and arsenic-bearing pyrite: Current Tl pollution in the Riotinto mine area

Abstract

Samples of an open-air pyrite roasting heap from the 19 th century in the Riotinto mine area (SW Spain) and surrounding sediments and soil along a seasonal surface runoff channel were analyzed to study thallium (Tl) phase transformations during historical roasting of Tl-bearing arsenian pyrite, secondary weathering processes, Tl dispersion and current environmental pollution. Results from Electron Probe Microanalyses (EPMA) indicate an even distribution of Tl in pyrite grains of an ore sample (22 mg kg-1 total Tl), suggesting that Tl is incorporated in the pyrite structure rather than in discrete Tl-sulfide microparticles. The roasting residue (122 mg kg-1 total Tl) consists mainly of hematite. EPMA suggested that Tl in the roasting residue and contaminated soil was cooccuring with Fe oxide particles, with a mean Tl point concentration of 0.12% in samples from the roasting residues. Total concentrations of Tl in soil samples decrease with distance from the roasting heap to 14 mg kg-1. X-ray absorption near-edge structure (XANES) spectra collected on pyrite roasting residue and a soil sample suggest that most Tl is Tl(I) substituting K in jarosite. Sequential extractions show that most Tl (85-99%) in the soil and sediment samples is concentrated in the residual fraction and, thus, is rather strongly bound. Lastly, water extracts indicate that colloidal particles (i.e. <1 µm size) may contribute to the dispersion of Tl around and away from the roasting heaps.

CH4 isotopic signatures of emissions from oil and gas extraction sites in Romania

“…In 2014, severe Tl contamination in drinking water (15 mg/L in the spring water) was discovered in northern Tuscany, Italy, resulting in a severe Tl accumulation in urine and hair of local residents (Campanella et al, 2016;Biagioni et al, 2017). China has abundant Tl-bearing mineral resources, and the mining and smelting activities have released large amounts of Tl into aquatic environments (Liu et al, 2010;Xu et al, 2019;Liu et al, 2020). Several rivers in South China such as the North River in Guangdong province, the Hejiang River in Guangxi province, and Xiannv Lake in Jiangxi province were contaminated by the discharge of wastewater containing high Tl.…”

Ecological Risk Assessment of Heavy Metals in Water Bodies around Typical Copper Mines in China

“…In recent years, with the improvement of China's industrial level, the development of the mining industry has accelerated. A large amount of solid waste and wastewater from mining has become the main cause of water pollution around the mine [1][2][3]. The main components of these solid wastes and wastewater are heavy metals.…”

Thallium and co-genetic trace elements in hydrothermal Fe-Mn deposits of Central Spain

“…Thallium is an important element used in superconductive materials (Murakami et al, 1996), medicine (Bauman et al, 1993;Kassis et al, 1983), electronics (Horn et al, 1983;Kaufman et al, 1970), chemical industries (Červeny et al, 1986;Gaikwad, 2011), and radiation dosimetry (Hitomi et al, 1999;Rahman et al, 1987) and it has accordingly been analyzed in various environments (Jacobson et al, 2005;Peter and Viraraghavan, 2005;Xiao et al, 2003;Zhou et al, 2008). Anthropogenic Tl pollution of soils and waters has been related to cement production, coal mining and burning, as well as metal sulfide mining and ore smelting (Belzile and Chen, 2017;Vanĕk et al, 2013;Lukaszewski et al, 2018;Liu, et al, 2018;Ghezzi et al, 2019;López-Arce et al, 2019;Cruz-Hernández et al, 2018).…”