TY - JOUR
T1 - Impacts of Sediment Particle Grain Size and Mercury Speciation on Mercury Bioavailability Potential
AU - Xu, Jiang
AU - Bland, Garret D.
AU - Gu, Yuan
AU - Ziaei, Hasti
AU - Xiao, Xiaoyue
AU - Deonarine, Amrika
AU - Reible, Danny
AU - Bireta, Paul
AU - Hoelen, Thomas P.
AU - Lowry, Gregory V.
N1 - Funding Information:
Portions of this research were carried out at the SSRL beamline 4–3 and 11–2, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. We thank Ryan Davis at SSRL (BL 4–3 and 11–2) for his support. The authors thank Chevron, the U.S. Army Engineer Research Office under contract W911NF1910063 to G.V.L., and the NSF and EPA funding under NSF Cooperative Agreement EF-1266252, Center for the Environmental Implications of NanoTechnology (CEINT) for partial financial support of the research.
Publisher Copyright:
© 2021 American Chemical Society
PY - 2021/9/21
Y1 - 2021/9/21
N2 - Particle-specific properties, including size and chemical speciation, affect the reactivity of mercury (Hg) in natural systems (e.g., dissolution or methylation). Here, terrestrial, river, and marine sediments were size-fractionated and characterized to correlate particle-specific properties of Hg-bearing solids with their bioavailability potential and measured biomethylation. Marine sediments contained ∼20-50% of the total Hg in the <0.5 μm size fraction, compared to only 0.5 and 3.0% in this size fraction for terrestrial and river sediments, respectively. X-ray absorption spectroscopy (XAS) analysis indicated that metacinnabar (β-HgS) was the main mercury species in a marine sediment, whereas organic Hg-thiol (Hg(SR)2) was the main mercury species in a terrestrial sediment. Single-particle inductively coupled plasma time-of-flight mass spectrometry analysis of the marine sediment suggests that half of the Hg in the <0.5 μm size fraction existed as individual nanoparticles, which were β-HgS based on XAS analyses. Glutathione-extractable mercury was higher for samples containing Hg(SR)2species than β-HgS species and correlated well with the amount of Hg biomethylation. This particle-scale understanding of how Hg speciation and particle size affect mercury bioavailability potential helps explain the heterogeneity in Hg methylation in natural sediments.
AB - Particle-specific properties, including size and chemical speciation, affect the reactivity of mercury (Hg) in natural systems (e.g., dissolution or methylation). Here, terrestrial, river, and marine sediments were size-fractionated and characterized to correlate particle-specific properties of Hg-bearing solids with their bioavailability potential and measured biomethylation. Marine sediments contained ∼20-50% of the total Hg in the <0.5 μm size fraction, compared to only 0.5 and 3.0% in this size fraction for terrestrial and river sediments, respectively. X-ray absorption spectroscopy (XAS) analysis indicated that metacinnabar (β-HgS) was the main mercury species in a marine sediment, whereas organic Hg-thiol (Hg(SR)2) was the main mercury species in a terrestrial sediment. Single-particle inductively coupled plasma time-of-flight mass spectrometry analysis of the marine sediment suggests that half of the Hg in the <0.5 μm size fraction existed as individual nanoparticles, which were β-HgS based on XAS analyses. Glutathione-extractable mercury was higher for samples containing Hg(SR)2species than β-HgS species and correlated well with the amount of Hg biomethylation. This particle-scale understanding of how Hg speciation and particle size affect mercury bioavailability potential helps explain the heterogeneity in Hg methylation in natural sediments.
KW - mercury association
KW - mercury bioavailability proxy
KW - mercury methylation
KW - mercury methylation indicator
KW - mercury nanoparticles
KW - sediment contamination
KW - spICP-TOF-MS
UR - http://www.scopus.com/inward/record.url?scp=85115640345&partnerID=8YFLogxK
U2 - 10.1021/acs.est.1c03572
DO - 10.1021/acs.est.1c03572
M3 - Article
C2 - 34505768
AN - SCOPUS:85115640345
VL - 55
SP - 12393
EP - 12402
JO - Environmental Science and Technology
JF - Environmental Science and Technology
SN - 0013-936X
IS - 18
ER -