Mercury (Hg) Mobility and Methylation Based on Hg Origin in Some Forest Soils in Czech Republic

The most important soil Hg fractions and species (total Hg, potentially mobilizable Hg and methyl Hg) from two mercury polluted sites with a historic pollution in Czech Republic were compared based on the origin of Hg and their speciation trough interaction with some of the soil properties. The first study site Libčice used to be a gold mine in the 19th and the first half of twentieth century. An amalgamation process has taken place at this location, therefore, Libčice site contains predominantly anthropogenic Hg which was introduced in Hg²⁺ form. The second study site Horní Luby was a cinnabar mine that was closed and reopened on multiple occasions in the period between sixteenth and nineteenth century. It contains both geogenic and anthropogenic Hg which was introduced in HgS form. Based on the total concentration of Hg both sites exceeding legislation limits (Libčice 0.10 to 36.2 mg kg⁻¹ and Horní Luby 1.35 to 90.00 mg kg⁻¹), these sites resent a potential risk for environment and ecosystem functioning, including human health. Furthermore, results show the difference in mobility and methylation of Hg between the horizon type (organic or mineral), caused by the different origin of Hg. These conditions also revealed many different pathways of Hg methylation process occurring at each individual site.