Formation and mobilization of methylmercury across natural and experimental sulfur deposition gradients

Staffan Åkerblom; Mats B Nilsson; Ulf Skyllberg; Erik Björn; Sofi Jonsson; Bo Ranneby; Kevin Bishop

doi:10.1016/j.envpol.2020.114398

Formation and mobilization of methylmercury across natural and experimental sulfur deposition gradients

Environ Pollut. 2020 Aug;263(Pt A):114398. doi: 10.1016/j.envpol.2020.114398. Epub 2020 Mar 17.

Authors

Staffan Åkerblom¹, Mats B Nilsson², Ulf Skyllberg², Erik Björn³, Sofi Jonsson⁴, Bo Ranneby⁵, Kevin Bishop⁶

Affiliations

¹ Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SE-756 51, Uppsala, Sweden. Electronic address: staffan.akerblom@slu.se.
² Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
³ Department of Chemistry, Umeå University, SE-901 87, Umeå, Sweden.
⁴ Department of Chemistry, Umeå University, SE-901 87, Umeå, Sweden; Department of Environmental Science and Analytical Chemistry, SE-11418 Stockholm University Stockholm, Sweden.
⁵ Department of Forest Economics, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
⁶ Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SE-756 51, Uppsala, Sweden.

PMID: 32229372
DOI: 10.1016/j.envpol.2020.114398

Abstract

We investigated the influence of sulfate (SO₄^2-) deposition and concentrations on the net formation and solubility of methylmercury (MeHg) in peat soils. We used data from a natural sulfate deposition gradient running 300 km across southern Sweden to test the hypothesis posed by results from an experimental field study in northern Sweden: that increased loading of SO₄^2- both increases net MeHg formation and redistributes methylmercury (MeHg) from the peat soil to its porewater. Sulfur concentrations in peat soils correlated positively with MeHg concentrations in peat porewater, along the deposition gradient similar to the response to added SO₄^2- in the experimental field study. The combined results from the experimental field study and deposition gradient accentuate the multiple, distinct and interacting roles of SO₄^2- deposition in the formation and redistribution of MeHg in the environment.

Keywords: Mercury; Methyl mercury; Methylation; Peatland; Sulfur.

MeSH terms

Environmental Monitoring
Mercury / analysis*
Methylmercury Compounds*
Soil
Sulfur
Sweden

Substances

Methylmercury Compounds
Soil
Sulfur
Mercury