Mediation of arsenic mobility by organic matter in mining-impacted sediment from sub-Arctic lakes: implications for environmental monitoring in a warming climate.

Autor: Miller CB; Centre for Ore Deposits and Earth Sciences (CODES), Department of Earth Science, University of Tasmania, Hobart, TAS 7001 Australia.; Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, ON K7L 3N6 Canada., Parsons MB; Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, ON K7L 3N6 Canada.; Geological Survey of Canada/Commission Géologique du Canada, Natural Resources Canada/Ressources Naturelles Canada, 1 Challenger Drive, Dartmouth, NS B2Y 4A2 Canada., Jamieson HE; Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, ON K7L 3N6 Canada., Ardakani OH; Geological Survey of Canada/Commission Géologique du Canada, Natural Resources Canada/Ressources Naturelles Canada, 3303 - 33 Street N.W., Calgary, AB T2L 2A7 Canada., Patterson RT; Ottawa-Carleton Geoscience Centre, Department of Earth Sciences, Carleton University, Ottawa, ON KIS 5B6 Canada., Galloway JM; Geological Survey of Canada/Commission Géologique du Canada, Natural Resources Canada/Ressources Naturelles Canada, 3303 - 33 Street N.W., Calgary, AB T2L 2A7 Canada.; Ottawa-Carleton Geoscience Centre, Department of Earth Sciences, Carleton University, Ottawa, ON KIS 5B6 Canada.
Jazyk: angličtina
Zdroj: Environmental earth sciences [Environ Earth Sci] 2022; Vol. 81 (4), pp. 137. Date of Electronic Publication: 2022 Feb 16.
DOI: 10.1007/s12665-022-10213-2
Abstrakt: Arsenic (As) is commonly sequestered at the sediment-water interface (SWI) in mining-impacted lakes through adsorption and/or co-precipitation with authigenic iron (Fe)-(oxy)hydroxides or sulfides. The results of this study demonstrate that the accumulation of organic matter (OM) in near-surface sediments also influences the mobility and fate of As in sub-Arctic lakes. Sediment gravity cores, sediment grab samples, and porewaters were collected from three lakes downstream of the former Tundra gold mine, Northwest Territories, Canada. Analysis of sediment using combined micro-X-ray fluorescence/diffraction, K-edge X-ray Absorption Near-Edge Structure (XANES), and organic petrography shows that As is associated with both aquatic (benthic and planktonic alginate) and terrestrially derived OM (e.g., cutinite, funginite). Most As is hosted by fine-grained Fe-(oxy)hydroxides or sulfide minerals (e.g., goethite, orpiment, lepidocrocite, and mackinawite); however, grain-scale synchrotron-based analysis shows that As is also associated with amorphous OM. Mixed As oxidation states in porewater (median = 62% As (V), 18% As (III); n  = 20) and sediment (median = 80% As (-I) and (III), 20% As (V); n  = 9) indicate the presence of variable redox conditions in the near-surface sediment and suggest that post-depositional remobilization of As has occurred. Detailed characterization of As-bearing OM at and below the SWI suggests that OM plays an important role in stabilizing redox-sensitive authigenic minerals and associated As. Based on these findings, it is expected that increased concentrations of labile OM will drive post-depositional surface enrichment of As in mining-impacted lakes and may increase or decrease As flux from sediments to overlying surface waters.
Supplementary Information: The online version contains supplementary material available at 10.1007/s12665-022-10213-2.
Competing Interests: Conflict of interestThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(© The Author(s) 2022.)
Databáze: MEDLINE
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