Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite
The chemical speciation of mercury (Hg), methyl mercury (MeHg), sulfur and iron was investigated in the sediment and porewater of Lake Ängessjön, a boreal, shallow (maximum depth 2.5 m), oligo-/dystrophic lake in northern Sweden. The lake receives terrestrial stream runoff from surrounding coniferou...
Published in: | Geochimica et Cosmochimica Acta |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Umeå universitet, Kemiska institutionen
2021
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Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-180656 https://doi.org/10.1016/j.gca.2020.11.022 |
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ftumeauniv:oai:DiVA.org:umu-180656 2023-10-09T21:54:38+02:00 Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite Skyllberg, Ulf Persson, Anna Tjerngren, Ida Kronberg, Rose-Marie Drott, Andreas Meili, Markus Björn, Erik 2021 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-180656 https://doi.org/10.1016/j.gca.2020.11.022 eng eng Umeå universitet, Kemiska institutionen Geochimica et Cosmochimica Acta, 0016-7037, 2021, 294, s. 106-125 orcid:0000-0001-9570-8738 http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-180656 doi:10.1016/j.gca.2020.11.022 ISI:000609493700007 Scopus 2-s2.0-85098468864 info:eu-repo/semantics/openAccess Mercury Methyl mercury Sulfur Iron Pyrite Mackinawite Metacinnabar Chemical speciation Mercury biogeochemistry Boreal lake Geochemistry Geokemi Article in journal info:eu-repo/semantics/article text 2021 ftumeauniv https://doi.org/10.1016/j.gca.2020.11.022 2023-09-22T13:59:11Z The chemical speciation of mercury (Hg), methyl mercury (MeHg), sulfur and iron was investigated in the sediment and porewater of Lake Ängessjön, a boreal, shallow (maximum depth 2.5 m), oligo-/dystrophic lake in northern Sweden. The lake receives terrestrial stream runoff from surrounding coniferous forest soils and peatlands having a low pH (4.6) and high concentrations of dissolved organic matter (DOM, annual average: 45 mg L−1), Fe (60 µM), sulfate (105 µM), inorganic Hg (1200 pM) and MeHg (250 pM). Sulfur K-edge XANES and Hg LIII-edge EXAFS spectroscopic measurements were used to characterize and quantify the sulfur speciation in the lake sediment at nine occasions, covering different seasons in the years of 2007 and 2009. In the surface sediment (0–3 cm) sulfate is reduced to zero-valent S and inorganic sulfide, that in turn reacts with Fe to form FeSm (mackinawite) and FeS2 (framboidal pyrite). The latter mineral becomes increasingly dominant by depth in the sediment. Thermodynamic modeling successfully predicted measured porewater concentrations of Hg in the sediment. Metacinnabar (β-HgS) and Hg(NOM-RS)2 complexes (the latter formed as a reaction between Hg(II) and thiol groups associated with natural organic matter, NOM-RSH) were the dominant forms of Hg(II) in the solid phase of sediments and Hg(II)-polysulfides (aq) dominated in the porewater. We argue that FeSm is a key component that indirectly controlled the Hg(II) speciation in the sediment by keeping the aqueous phase concentration of inorganic sulfide in the 0.5–2 µM range throughout the year. Besides providing a pool of readily soluble inorganic sulfide for formation of β-HgS(s), as demonstrated by previously reported EXAFS experiments, we further suggest FeSm may serve as a precursor for the formation of a more crystalline (less soluble) β-HgS(s) phase than present in environments devoid of FeSm. Support for this was provided by comparing our results with previously reported thermodynamic modelling results of Hg(II) and MeHg solubility in ... Article in Journal/Newspaper Northern Sweden Umeå University: Publications (DiVA) Boreal Lake ENVELOPE(-127.670,-127.670,58.802,58.802) Geochimica et Cosmochimica Acta 294 106 125 |
institution |
Open Polar |
collection |
Umeå University: Publications (DiVA) |
op_collection_id |
ftumeauniv |
language |
English |
topic |
Mercury Methyl mercury Sulfur Iron Pyrite Mackinawite Metacinnabar Chemical speciation Mercury biogeochemistry Boreal lake Geochemistry Geokemi |
spellingShingle |
Mercury Methyl mercury Sulfur Iron Pyrite Mackinawite Metacinnabar Chemical speciation Mercury biogeochemistry Boreal lake Geochemistry Geokemi Skyllberg, Ulf Persson, Anna Tjerngren, Ida Kronberg, Rose-Marie Drott, Andreas Meili, Markus Björn, Erik Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
topic_facet |
Mercury Methyl mercury Sulfur Iron Pyrite Mackinawite Metacinnabar Chemical speciation Mercury biogeochemistry Boreal lake Geochemistry Geokemi |
description |
The chemical speciation of mercury (Hg), methyl mercury (MeHg), sulfur and iron was investigated in the sediment and porewater of Lake Ängessjön, a boreal, shallow (maximum depth 2.5 m), oligo-/dystrophic lake in northern Sweden. The lake receives terrestrial stream runoff from surrounding coniferous forest soils and peatlands having a low pH (4.6) and high concentrations of dissolved organic matter (DOM, annual average: 45 mg L−1), Fe (60 µM), sulfate (105 µM), inorganic Hg (1200 pM) and MeHg (250 pM). Sulfur K-edge XANES and Hg LIII-edge EXAFS spectroscopic measurements were used to characterize and quantify the sulfur speciation in the lake sediment at nine occasions, covering different seasons in the years of 2007 and 2009. In the surface sediment (0–3 cm) sulfate is reduced to zero-valent S and inorganic sulfide, that in turn reacts with Fe to form FeSm (mackinawite) and FeS2 (framboidal pyrite). The latter mineral becomes increasingly dominant by depth in the sediment. Thermodynamic modeling successfully predicted measured porewater concentrations of Hg in the sediment. Metacinnabar (β-HgS) and Hg(NOM-RS)2 complexes (the latter formed as a reaction between Hg(II) and thiol groups associated with natural organic matter, NOM-RSH) were the dominant forms of Hg(II) in the solid phase of sediments and Hg(II)-polysulfides (aq) dominated in the porewater. We argue that FeSm is a key component that indirectly controlled the Hg(II) speciation in the sediment by keeping the aqueous phase concentration of inorganic sulfide in the 0.5–2 µM range throughout the year. Besides providing a pool of readily soluble inorganic sulfide for formation of β-HgS(s), as demonstrated by previously reported EXAFS experiments, we further suggest FeSm may serve as a precursor for the formation of a more crystalline (less soluble) β-HgS(s) phase than present in environments devoid of FeSm. Support for this was provided by comparing our results with previously reported thermodynamic modelling results of Hg(II) and MeHg solubility in ... |
format |
Article in Journal/Newspaper |
author |
Skyllberg, Ulf Persson, Anna Tjerngren, Ida Kronberg, Rose-Marie Drott, Andreas Meili, Markus Björn, Erik |
author_facet |
Skyllberg, Ulf Persson, Anna Tjerngren, Ida Kronberg, Rose-Marie Drott, Andreas Meili, Markus Björn, Erik |
author_sort |
Skyllberg, Ulf |
title |
Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
title_short |
Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
title_full |
Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
title_fullStr |
Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
title_full_unstemmed |
Chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
title_sort |
chemical speciation of mercury, sulfur and iron in a dystrophic boreal lake sediment, as controlled by the formation of mackinawite and framboidal pyrite |
publisher |
Umeå universitet, Kemiska institutionen |
publishDate |
2021 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-180656 https://doi.org/10.1016/j.gca.2020.11.022 |
long_lat |
ENVELOPE(-127.670,-127.670,58.802,58.802) |
geographic |
Boreal Lake |
geographic_facet |
Boreal Lake |
genre |
Northern Sweden |
genre_facet |
Northern Sweden |
op_relation |
Geochimica et Cosmochimica Acta, 0016-7037, 2021, 294, s. 106-125 orcid:0000-0001-9570-8738 http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-180656 doi:10.1016/j.gca.2020.11.022 ISI:000609493700007 Scopus 2-s2.0-85098468864 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.gca.2020.11.022 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
294 |
container_start_page |
106 |
op_container_end_page |
125 |
_version_ |
1779318289899454464 |