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 - 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
SN - 0013-936X
VL - 55
SP - 12393
EP - 12402
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 18
ER -