Mercury Isotopes in Earth and Environmental Sciences

Blum, Joel D.; Sherman, Laura S.; Johnson, Marcus W.

doi:10.1146/annurev-earth-050212-124107

Cited by 571 publications

(743 citation statements)

References 94 publications

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“…The Cache Creek ratio falls between literature averages for freshwater fish (1.28±0.01; 1SE, n=135) 23 and marine fish (1.20±0.01; 1SE, n=60), 23 and is similar to biota from nearby rivers (Yuba R.=1.27±0.03 and Eel R.=1.28±0.08). 42,44 The Yolo Bypass ratio is on the low end of the range reported for MMHg photodegradation experiments (1.17 to 1.38), 75 but still comparable to Cache Creek and also to forest biota from northern Michigan (1.21±0.03) 43 and northern California (1.15±0.06, n=10) 44 .…”

Section: Mmhg Photodegradationmentioning

confidence: 57%

“…23 Experimental studies of Hg isotope fractionation have demonstrated MDF during biotic (i.e, Hg(II) methylation, MeHg degradation, Hg(II) reduction) [24][25][26][27] and abiotic (IHg sorption, coprecipitation, etc.) 28,29 reactions while large magnitude odd-mass-number MIF (>0.5‰) occurs primarily during photochemical reactions.…”

Section: Introductionmentioning

confidence: 99%

“…28,29 reactions while large magnitude odd-mass-number MIF (>0.5‰) occurs primarily during photochemical reactions. 23,30 The Hg isotopic composition of sediment has previously been used to identify anthropogenic Hg sources and trace their transport and deposition in river and estuarine environments. [31][32][33][34][35] Hg isotopes have also been measured in a variety of Hg mine waste materials, including calcines and CA Coast Range Hg-ores.…”

Section: Introductionmentioning

confidence: 99%

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Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

Donovan

Singer

Marvin-DiPasquale

et al. 2016

Science of The Total Environment

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Section: Mmhg Photodegradationmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

Donovan

Singer

Marvin-DiPasquale

et al. 2016

Science of The Total Environment

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“…Hg stable isotope data can further verify a volcanic source of Hg spikes 20,24 . According to Blum et al 25 , Hg stable isotopes exhibit both mass-dependent fractionation (MDF, reported as δ 202 Hg) and mass-independent fractionations (MIF, reported as Δ 199 Hg) in the environment and can be used as multi-dimensional tracers to discriminate Hg sources, transport and cycling [25][26][27][28] . We used the nomenclature of Blum and Bergquist 29 to describe mercury isotope compositions, whereby Hg isotopic composition is reported in δ…”

Section: Mercury As a Proxy For Lip Eventsmentioning

confidence: 99%

“…Mercury can undergo complex geochemical transformation processes in the environment, that may induce mass dependent fractionation (MDF) and mass independent fractionation (MIF) of Hg isotopes 25,45,46 . MDF can occur during various physical, chemical, or biological transformations of Hg, whereas MIF is generated through a more limited set of pathways (mostly photochemical), making it a more conservative tracer 46 .…”

Section: A Late Ordovician Lip Eventmentioning

confidence: 99%

Mercury Spikes Suggest Volcanic Driver of the Ordovician-Silurian Mass Extinction

Qing¹,

Zhao²,

Wang³

et al. 2017

Geological Society of America Abstracts With Programs

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The second largest Phanerozoic mass extinction occurred at the Ordovician-Silurian (O-S) boundary. However, unlike the other major mass extinction events, the driver for the O-S extinction remains uncertain. The abundance of mercury (Hg) and total organic carbon (TOC) of Ordovician and early Silurian marine sediments were analyzed from four sections (Huanghuachang, Chenjiahe, Wangjiawan and Dingjiapo) in the Yichang area, South China, as a test for evidence of massive volcanism associated with the O-S event. Our results indicate the Hg concentrations generally vary in parallel with TOC, and that the Hg/TOC ratios remain low and steady state through the Early and Middle Ordovician. However, Hg concentrations and the Hg/TOC ratio increased rapidly in the Late Katian, and have a second peak during the Late Hirnantian (Late Ordovician) that was temporally coincident with two main pulses of mass extinction. Hg isotope data display little to no variation associated with the Hg spikes during the extinction intervals, indicating that the observed Hg spikes are from a volcanic source. These results suggest intense volcanism occurred during the Late Ordovician, and as in other Phanerozoic extinctions, likely played an important role in the O-S event.Refinements in radio-isotopic dating techniques has demonstrated a strong temporal link between Large Igneous Province (LIP) volcanism and four out of the five largest mass extinctions in the Phanerozoic, leading to suggestions that LIP events have devastating effects on global ecosystems that in some ways mirrors concerns over modern anthropogenic impacts on the planet [1][2][3][4] . The one anomaly is the Ordovician-Silurian (O-S) mass extinction, the second largest of the "Big Five" extinctions. In terms of species loss the O-S represented about 86% of marine life 5,6 , including the elimination of graptolites 7-9 and brachiopods 10, 11 . The triggering mechanism of the O-S mass extinction has been extensively debated, and various hypotheses have been proposed, including gamma ray burst and bolide impact 12,13 ; however, the cause still remains highly controversial. Intense Late Ordovician volcanism was also suggested as a potential extinction mechanism 14,15 , although no clear geologic record of a Late Ordovician LIP event has been demonstrated. The age of the event makes it possible that any geologic record has been lost 15 . Given this, we tested for indirect evidence of volcanism at the O-S extinction boundary by examining the Hg record from classic sections in south China. Here we show that significant spikes in Hg concentrations occur at the O-S extinction, along with Hg stable isotope data that indicate a volcanic source for these spikes. We suggest that this reflects Hg loading by a LIP event. If correct, these results demonstrate that LIP events have indeed played a critical role in the evolution of life through time. Mercury as a Proxy for LIP eventsVolcanic eruptions are the main natural source of Hg to the environment 16 . Sanei et al. 17 demonstrated that th...

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Coupling atmospheric mercury isotope ratios and meteorology to identify sources of mercury impacting a coastal urban‐industrial region near Pensacola, Florida, USA

Demers

Sherman

Blum

et al. 2015

Global Biogeochemical Cycles

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Identifying the anthropogenic and natural sources of mercury (Hg) emissions contributing to atmospheric mercury on local, regional, and global scales continues to be a grand challenge. The relative importance of various direct anthropogenic emissions of mercury, in addition to natural geologic sources and reemission of previously released and deposited mercury, differs regionally and temporally. In this study, we used local‐scale, mesoscale, and synoptic‐scale meteorological analysis to couple the isotopic composition of ambient atmospheric mercury with potential sources of mercury contributing to a coastal urban‐industrial setting near a coal‐fired power plant in Pensacola, Florida, USA. We were able to broadly discern four influences on the isotopic composition of ambient atmospheric mercury impacting this coastal urban‐industrial region: (1) local to regional urban‐industrial anthropogenic emissions (mean δ202Hg = 0.44 ± 0.05‰, 1SD, n = 3), (2) marine‐influenced sources derived from the Gulf of Mexico (mean δ202Hg = 0.77 ± 0.15‰, 1SD, n = 4), (3) continental sources associated with north‐northwesterly flows from within the planetary boundary layer (mean δ202Hg = 0.65 ± 0.04‰, 1SD, n = 3), and (4) continental sources associated with north‐northeasterly flows at higher altitudes (i.e., 2000 m above ground level; mean δ202Hg = 1.10 ± 0.21‰, 1SD, n = 8). Overall, these data, in conjunction with previous studies, suggest that the background global atmospheric mercury pool is characterized by moderately positive δ202Hg values; that urban‐industrial emissions drive the isotopic composition of ambient atmospheric mercury toward lower δ202Hg values; and that air‐surface exchange dynamics across vegetation and soils of terrestrial ecosystems drive the isotopic composition of ambient atmospheric mercury toward higher positive δ202Hg values. The data further suggest that mass‐independent fractionation (MIF) of both even‐mass‐ and odd‐mass‐number isotopes, likely generated by photochemical reactions in the atmosphere or during reemission from terrestrial and aquatic ecosystems, can be obscured by mixing with anthropogenic emissions having different MIF signatures.

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Mercury Isotopes in Earth and Environmental Sciences

Cited by 571 publications

References 94 publications

Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

Mercury Spikes Suggest Volcanic Driver of the Ordovician-Silurian Mass Extinction

Coupling atmospheric mercury isotope ratios and meteorology to identify sources of mercury impacting a coastal urban‐industrial region near Pensacola, Florida, USA

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