A5085100568- Mercury impact and mitigation studies
- Isotope Analysis in Ecology
- Heavy metals in environment
- Toxic Organic Pollutants Impact
- Heavy Metal Exposure and Toxicity
- Geochemistry and Elemental Analysis
- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Nuclear Physics and Applications
- Marine animal studies overview
- Paleontology and Stratigraphy of Fossils
- Groundwater and Isotope Geochemistry
- Chemical Analysis and Environmental Impact
- Marine and coastal ecosystems
- Mining and Resource Management
- Radioactive contamination and transfer
- Fire effects on ecosystems
- Astro and Planetary Science
- Atmospheric and Environmental Gas Dynamics
- Radioactive element chemistry and processing
- Geochemistry and Geologic Mapping
- Radioactivity and Radon Measurements
- Marine Biology and Ecology Research
- Marine Bivalve and Aquaculture Studies
- Atomic and Molecular Physics
University of Toronto
2015-2025
Toronto Public Health
2016-2018
University of Michigan
2004-2008
Massachusetts Institute of Technology
2000-2007
Rutgers, The State University of New Jersey
2007
Lawrence Livermore National Laboratory
1998-2004
Mercury (Hg) isotopes can be used as tracers of Hg biogeochemical pathways in the environment. The photochemical reduction aqueous species by natural sunlight leads to both mass-dependent fractionation (MDF) and mass-independent (MIF) odd-mass isotopes, with relation between MIF for two odd being distinct different photoreduction pathways. Large variations MDF are observed fish provide new insights into sources bioaccumulation food webs. also estimate loss methylmercury via aquatic ecosystems.
The end-Triassic mass extinction overlapped with the eruption of Central Atlantic Magmatic Province (CAMP), and release CO2 other volcanic volatiles has been implicated in extinction. However, timing marine biotic recovery versus CAMP eruptions remains uncertain. Here we use Hg concentrations isotopes as indicators volcanism continental shelf sediments, primary archive faunal data. In Triassic–Jurassic strata, Muller Canyon, Nevada, levels rise interval, peak before appearance first Jurassic...
Abstract Forest biomass and soils represent some of the largest reservoirs actively cycling mercury (Hg) on Earth, but many uncertainties exist regarding source fate Hg in forest ecosystems. We systematically characterized stable isotope compositions foliage, litter, mineral soil horizons across 10 sites contiguous United States. The mass‐independent signatures all depth profiles are more consistent with those atmospheric Hg(0) than Hg(II), indicating that is larger to Within litter...
Abstract Mercury emissions from artisanal and small-scale gold mining throughout the Global South exceed coal combustion as largest global source of mercury. We examined mercury deposition storage in an area Peruvian Amazon heavily impacted by mining. Intact forests near receive extremely high inputs experience elevated total methylmercury atmosphere, canopy foliage, soils. Here we show for first time that intact forest intercepts large amounts particulate gaseous mercury, at a rate...
In nearly a dozen open‐ocean fertilization experiments conducted by more than 100 researchers from 20 countries, adding iron at the sea surface has led to distinct increases in photosynthesis rates and biomass. These confirmed hypothesis proposed late John Martin [ , 1990] that dissolved concentration is key variable controls phytoplankton processes ocean waters However, measurement of seawater remains difficult task Bruland Rue 2001] with significant interlaboratory differences apparent...
There is a need to distinguish among sources of Hg the atmosphere in order more fully understand global pollution. In this study we investigate whether coal deposits within United States, China, and Russia-Kazakhstan, which are three five greatest coal-producing regions, have diagnostic isotopic fingerprints that can be used discriminate sources. We also composition modern organic soil horizons developed areas distant from point North America. Mercury stored displays wide range both mass...
Research Article| December 01, 2009 The Odds and Evens of Mercury Isotopes: Applications Mass-Dependent Mass-Independent Isotope Fractionation Bridget A. Bergquist; Bergquist 1Department Geology, University Toronto Toronto, Ontario, M5S 3B1 Canada E-mail: bergquist@geology.utoronto.ca Search for other works by this author on: GSW Google Scholar Joel D. Blum 2Department Geological Sciences, Michigan Ann Arbor, MI 48109, USA jdblum@umich.edu Elements (2009) 5 (6): 353–357....
Mercury (Hg) undergoes systematic stable isotopic fractionation; therefore, signatures of Hg may provide a new tool to track sources, sinks, and dominant chemical transformation pathways in the environment. We investigated fractionation by Hg(II) resistant (HgR) bacteria expressing mercuric reductase (MerA) enzyme. The composition both reactant added growth medium volatilized product (Hg(0)) was measured using cold vapor generation multiple collector inductively coupled plasma mass...
Thallium (Tl) has been widely used as an internal standard for mass bias correction during high precision mercury (Hg) isotope ratio measurements using multi-collector inductively coupled plasma spectrometry (MC-ICP-MS).
Mercury (Hg) stable isotope fractionation has been widely used to trace Hg sources and transformations in the environment, although many important processes remain unknown. Here, we describe during abiotic dark oxidation of dissolved elemental Hg(0) presence thiol compounds natural humic acid. We observe equilibrium mass-dependent (MDF) with enrichment heavier isotopes oxidized Hg(II) a small negative mass-independent (MIF) owing nuclear volume effects. The measured factors for MDF MIF...
Detailed depth profiles and surface transects of dissolved iron (DFe defined by 0.4‐μm filtration) were investigated on three cruises in the subtropical tropical Atlantic Ocean where dust deposition varied 3 orders magnitude. Surface DFe Mn concentrations reflected trends, but are not proportional to estimated inputs. Using estimates atmospheric flux DFe, residence times calculated be order 1 5 months. Deepwater with water masses depending their source, age, transit pathways. At a site...
Monomethylmercury (MMHg) is a toxic pollutant that bioaccumulates in aquatic food webs. A major mechanism limits MMHg uptake by biota photodemethylation surface waters. Recently, the extent of mass-independent fractionation (MIF) Hg isotopes preserved fish being used to quantify this sink. Here, effects different types and amounts DOM on MIF during were investigated assess how variable enrichment factors may be with respect changing binding sites. From experiments conducted varying reduced...
Large Igneous Provinces (LIPs) are associated with a significant number of mass extinctions and ocean anoxic events (OAEs) during the Phanerozoic. However, role LIPs in triggering sustaining biotic environmental crises is controversial (e.g., [Bond Wignall, 2014][1]). These
Abstract During Arctic springtime, halogen radicals oxidize atmospheric elemental mercury (Hg 0 ), which deposits to the cryosphere. This is followed by a summertime Hg peak that thought result mostly from terrestrial inputs Ocean, photoreduction and emission air. The large contribution Ocean global atmosphere has raised concern over potential release of permafrost Hg, via rivers coastal erosion, with warming. Here we investigate isotope variability atmospheric, marine, Hg. We observe highly...
Non-quantitative Hg cold-vapor generation can compromise the accuracy of isotope analysis, and it should be monitored optimized by performing matrix separation, adopting design gas–liquid separators, tuning sample uptake rate.