Distribution and Speciation of Mercury in Mine Waste Dumps

Abstract

Mine waste dumps of historic mercury mines represent environmental threat. In the central Czech Republic, Hg ores were mined at two sites for more than 150 years. Mine wastes collected from dumps near Hg mines were elevated in total Hg (up to 120 microg(-1)). Thermal-desorption method revealed that most of Hg (>80%) in studied waste material was present as cinnabar (HgS), that is relatively stable in soils and resistant to formation of highly toxic methyl-Hg. Nevertheless minor part (<14%) of total Hg was identified as mineral surface bound Hg, which might undergo methylation and thus represents potential long-term environmental risk.

Distribution and speciation of mercury in soil in the area of an ancient mercury ore roasting site, Frbejžene trate (Idrija area, Slovenia)

“…HgS dissolution has been reported in the presence of high sulphide concentrations and at pHN 6 (Wang et al, 2003in Hojdová et al, 2008. Regarding extremely high total Hg concentrations, large amounts of potentially transformable non-cinnabar Hg compounds exist at the area of the studied roasting site, which have the potential to be transformed to bioavailable Hg compounds such as methylmercury (Barnett et al, 1997;Kim et al, 2000).…”

Thermo-desorption: A valid tool for mercury speciation in soils and sediments?

“…Direct measurement of Hg species by XAFS is possible, but requires total Hg concentration above 100 mg kg −1 , restricting its applicability to contaminated sites. In the last decades, thermo-desorption has increasingly been used for Hg speciation in solid matrices (Biester and Scholz, 1997;Bollen et al, 2008;Higueras et al, 2003;Hojdová et al, 2008Hojdová et al, , 2009Piani et al, 2005;Rallo et al, 2010;Rumayor et al, 2013). This technique allows different Hg-binding forms to be distinguished in soils and sediments based on the thermal release of Hg species.…”

The Legacy of Mercury Contamination from a Past Leather Manufacturer and Health Risk Assessment in an Urban Area (Pisa Municipality, Italy)

“…The E a obtained in this study was close to the enthalpy of the Hg 0 liq → Hg 0 gas reaction (about 14 Kcal/mol), and might reflect the vaporization of elemental Hg more deeply retained within the soil structure, compared with that represented by peak #1. Indeed, a double peak for Hg 0 release with a maximum at approximately 100 • C and 200 • C has been reported in the literature (e.g., [76]) and ascribed to Hg 0 as variably bound to Fe oxydydroxides, while a higher desorption temperature (200-300 • C) is attributed to matrix bound Hg 2+ [69,77,78].…”