Article
Speciation and Mobility of Mercury in Soils Contaminated by Legacy Emissions from a Chemical Factory in the Rhône Valley in Canton of Valais, Switzerland Robin Sue Gilli 1 , Claudine Karlen 1 ID , Mischa Weber 1 , Johanna Rüegg 1 , Kurt Barmettler 1 , Harald Biester 2 , Pascal Boivin 3 and Ruben Kretzschmar 1, * ID 1
2 3
*
Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, CHN, ETH Zurich, 8092 Zurich, Switzerland;
[email protected] (R.S.G.);
[email protected] (C.K.);
[email protected] (M.W.);
[email protected] (J.R.);
[email protected] (K.B.) Institute of GeoEcology, Division of Environmental Geochemistry, Technische Universität Braunschweig, 38106 Braunschweig, Germany;
[email protected] Soils and Substrates Group in TNE-hepia, University of Applied Science and Arts Western Switzerland, 1202 Geneva, Switzerland;
[email protected] Correspondence:
[email protected]; Tel.: +41-(0)44-633-6003
Received: 16 June 2018; Accepted: 24 July 2018; Published: 30 July 2018
Abstract: Legacy contamination of soils and sediments with mercury (Hg) can pose serious threats to the environment and to human health. Assessing risks and possible remediation strategies must consider the chemical forms of Hg, as different Hg species exhibit vastly different environmental behaviors and toxicities. Here, we present a study on Hg speciation and potential mobility in sediments from a chemical factory site, and soils from nearby settlement areas in the canton of Valais, Switzerland. Total Hg ranged from 0.5 to 28.4 mg/kg in the soils, and 3.5 to 174.7 mg/kg in the sediments, respectively. Elemental Hg(0) was not detectable in the soils by thermal desorption analysis. Methylmercury, the most toxic form of Hg, was present at low levels in all soils (
