In:
Environmental Science: Processes & Impacts, Royal Society of Chemistry (RSC), Vol. 24, No. 10 ( 2022), p. 1748-1757
Abstract:
Tree bark near former mercury (Hg) mines and roasting plants is known to have exceptionally high (up to several mg kg −1 ) Hg concentrations. This study explores the change of Hg speciation with depth (down to 25–30 mm from the outermost surface) in black pine ( Pinus nigra ) bark by means of high-resolution X-ray absorption near edge structure (HR-XANES) spectroscopy at the Hg L III -edge. Principal component analysis and linear combination fitting applied to the HR-XANES spectra suggested that in the outermost layer (∼0–2 mm from the surface), roughly 50% of Hg is in the form of nanoparticulate metacinnabar (nano-β-HgS). A progressive increase in Hg-organic species (Hg bound to thiol groups) is found in deeper bark layers, while nano-β-HgS may decrease below the detection limit in the deepest layers. Notably, bark layers did not contain cinnabar (α-HgS), which was found in the nearby soils along with β-HgS (bulk), nor Hg 0 , which is the main Hg species in the atmosphere surrounding the sampled trees. These observations suggested that nano-β-HgS, at least in part, does not originate from mechanically trapped wind-blown particulates from the surrounding soil, but may be the product of biochemical reactions between gaseous elemental Hg and the bark tissue.
Type of Medium:
Online Resource
ISSN:
2050-7887
,
2050-7895
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2022
detail.hit.zdb_id:
2703791-5
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