Occurrence and transformation of mercury in formerly contaminated soils due to operation of amalgamation techniques and assessment of consequences

Abstract

Soils formerly contaminated with mercury due to the implementation of amalgamation processes at two localities in the Czech Republic were analyzed to assess the impact of such contamination on both the environment and human health. One site is an abandoned gold mine at Libčice, where, in the past, gold was extracted from the raw ore by the mercury amalgamation technique. The second site is the environs of a small building in Prague where dental surgery was formerly undertaken. Soils were tested for total mercury (T-Hg), elemental mercury (Hg⁰), methylmercury (MeHg⁺), phenylmercury (PhHg⁺), and gaseous elemental mercury (GEM). The T-Hg concentrations in both localities exceeded many times the maximum permissible limit for soils in the Czech Republic. The most contaminated soils were found around the dental surgery releasing GEM at concentrations of up to 1308 ng m⁻³, which can represent a danger mainly for people through inhalation. Soils near the abandoned gold mine release GEM at concentrations of up to 26 ng m⁻³, which indicates a long-term burden on the environment and a danger for surrounding farmland.

Keywords:

• mercury species
• soil
• abandoned gold mine
• dental surgery
• exposure assessment

Acknowledgements

The authors are grateful to Dr. Slavka Grohová (The National Institute of Public Health, Prague) for her valuable help in gaseous elemental mercury measurements; corrections and the language improvement were provided by a native speaker (UK) with science education.

Additional information

Funding

Financial support for this study was provided by the Grant Agency of the Czech Republic, Project P503/12/0682 and by the Masaryk University Brno, Project MUNI/A/1288/2017.