title: The role of authigenic sulfides in immobilization of potentially toxic metals in the Bagno Bory wetland, southern Poland.
abstract: The supply of Cd, Cu, Fe, Pb, Zn, and Tl into a wetland in the industrial area of Upper Silesia, southern Poland via atmospheric precipitation and dust deposition has been counterbalanced by the biogenic metal sulfide crystallization in microsites of the thin (<30 cm) peat layer, despite the overall oxidative conditions in the wetland. Disequilibrium of the redox reactions in the peat pore water (pH 5.4-6.2) caused by sulfate-reducing microorganisms has resulted in the localized decrease in Eh and subsequent precipitation of micron- and submicron-sized framboidal pyrite, spheroidal ZnS and (Zn,Cd)S, and galena as revealed by high-resolution scanning electron microscopy (SEM)/energy dispersive spectrometer (EDS). Saturation index for each sulfide is at a maximum within the calculated Eh range of -80 and -146 mV. Lead was also immobilized in galena deposited in fungal filaments, possibly at a higher Eh. Thallium (up to 3 mg kg(-1)) in the peat strongly correlates with Zn, whereas Cu (up to 55 mg kg(-1)) co-precipitated with Pb. The metal sulfides occur within microbial exudates, which protect them from oxidation and mechanical displacement. Vertical distribution of toxic metals in the peat layer reflects differences in pollution loads from atmospheric deposition, which has been much reduced recently.
authors.affiliation: Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200, Sosnowiec, Poland. beata.smieja-krol@us.edu.pl.
authors.forename: Beata
authors.identifier: http://orcid.org/0000-0001-5181-1821
authors.initials: B
authors.lastname: Smieja-Król
authors.affiliation: Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200, Sosnowiec, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Janeczek
authors.affiliation: Department of Environmental Monitoring, Central Mining Institute, Plac Gwarków 1, 40-166, Katowice, Poland.
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Bauerek
authors.affiliation: Centre for Geobiology and Department of Earth Science, University of Bergen, Allégaten 41, 5007, Bergen, Norway.
authors.forename: Ingunn H
authors.initials: IH
authors.lastname: Thorseth
mesh_terms: D019187:Cadmium Compounds / Q000032:analysis; D005296:Ferrous Compounds / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis; D007854:Lead / Q000032:analysis; D010084:Oxidation-Reduction; D011044:Poland; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D013440:Sulfides / Q000032:analysis; D053833:Wetlands; D017967:Zinc Compounds / Q000032:analysis
chemical_list: D019187:Cadmium Compounds; D005296:Ferrous Compounds; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides; D017967:Zinc Compounds; C034939:cadmium sulfide; C011342:pyrite; C018391:lead sulfide; D007854:Lead; D007501:Iron; C031238:zinc sulfide; C022597:ferrous sulfide
keywords: Biomineralization; Metal sulfide; Redox disequilibrium; Wetland