A5085772624- Mercury impact and mitigation studies
- Isotope Analysis in Ecology
- Toxic Organic Pollutants Impact
- Heavy metals in environment
- Heavy Metal Exposure and Toxicity
- Fish Ecology and Management Studies
- Marine animal studies overview
- Water Treatment and Disinfection
- Microbial Community Ecology and Physiology
- Geochemistry and Elemental Analysis
- Hydrology and Watershed Management Studies
- Per- and polyfluoroalkyl substances research
- Aquatic Invertebrate Ecology and Behavior
- Environmental DNA in Biodiversity Studies
- Atmospheric chemistry and aerosols
- Conservation Techniques and Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Hydrology and Sediment Transport Processes
- Mining and Resource Management
Environmental Protection Agency
2020-2025
University of Wisconsin–Madison
2015-2023
United States Geological Survey
2018-2020
Upper Midwest Water Science Center
2018-2020
University of Wisconsin System
2018
Madison Group (United States)
2016
Abstract Sedimentary records from the northwest margin of Pangea and Tethys show anomalously high Hg levels at latest Permian extinction boundary. Background δ202Hg values are consistent with normal marine conditions but exhibit negative shifts coincident increased concentrations. isotope mass-independent fractionation (Δ199Hg) trends volcanic input in deep-water environments. In contrast, nearshore environments have Δ199Hg signatures enhanced soil and/or biomass input. We hypothesize that...
Sources of mercury (Hg) in Great Lakes sediments were assessed with stable Hg isotope ratios using multicollector inductively coupled plasma mass spectrometry. An isotopic mixing model based on mass-dependent (MDF) and mass-independent fractionation (MIF) (δ202Hg Δ199Hg) identified three primary sources for sediments: atmospheric, industrial, watershed-derived. Results indicate atmospheric dominate Huron, Superior, Michigan while watershed-derived industrial Erie Ontario sediments. Anomalous...
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).
Abstract During the past few years, evidence of mass independent fractionation (MIF) for mercury (Hg) isotopes have been reported in Earth’s surface reservoirs, mainly assumed to be formed during photochemical processes. However, magnitude Hg-MIF interior pools crust is largely unknown. Here, we significant variation signature (Δ 199 Hg: −0.24 ~ + 0.18‰) sphalerites collected from 102 zinc (Zn) deposits China, indicating that can recorded into geological recycling crustal material. Changing...
Mercury (Hg) methylation is a microbially mediated process that converts inorganic Hg into bioaccumulative, neurotoxic methylmercury (MeHg). The metabolic activity of methylating organisms highly dependent on biogeochemical conditions, which subsequently influences MeHg production. However, our understanding the ecophysiology methylators in natural ecosystems still limited. Here, we identified potential locations production anoxic, sulfidic hypolimnion freshwater lake. At these sites, used...
Identifying the sources of methylmercury (MeHg) and tracing transformations mercury (Hg) in aquatic food web are important components effective strategies for managing current legacy Hg sources. In our previous work, we measured stable isotopes (δ202Hg, Δ199Hg, Δ200Hg) Laurentian Great Lakes estimated source contributions to bottom sediment. Here, identify isotopically distinct signatures trout (Salvelinus namaycush) walleye (Sander vitreus), driven by both food-web water-quality...
Abstract The Tibetan Plateau (TP), known as the “Third Pole”, is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in globe leads to environmental changes, which may affect loading, transport and deposition of Hg environment. However, history geochemical cycling TP still uncertain. Our records isotopes sediment profiles two largest lakes TP, Lake Qinghai Nam Co, show increased influx since last century, with maximum enrichment ratios 5.4 3.5...
Significance Elevated mercury in fish poses risks to fish-consuming wildlife and humans. Tracing sources of by analyzing stable isotope ratios leads improved source-receptor understanding natural resource management. This work utilizes sediment archives trace the response recent domestic mitigation actions. Fish sediments rapidly responded a source perturbation contemporaneous with reduction late 1980s. Subsequently, energetic pathways were altered due dreissenid invasions, which dampened...
Carlin-style (sediment-hosted, "invisible" gold) and epithermal gold deposits are commonly enriched in mercury (Hg), but the source of this metal is not well-known. In world, association Hg with often related to magmatism; however, it still unclear whether magmatism serves as a direct or only an energy that drives hydrothermal circulation leaches from sedimentary country rocks. Here, we use stable isotopes directly indicate major deposit (Shuiyindong) two small (Xianfeng Sishanlinchang)...
The strongest evidence for anthropogenic alterations to the global mercury (Hg) cycle comes from historical records of deposition preserved in lake sediments. Hg isotopes have added a new dimension these sedimentary archives, promising additional insights into source apportionment and biogeochemical processing. Presently, most interpretations changes are constrained small number locally contaminated ecosystems. Here, we describe natural isotope suite dated sediment cores collected various...
Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human wildlife health. Mercury (Hg) is a contaminant concern many these highly urbanized industrialized regions, one which Saint Louis River estuary (SLRE), second largest tributary Lake Superior. The SLRE has legacy Hg drives high concentrations sediments, but it unclear whether...
Abstract Mercury (Hg) concentrations and Hg isotopic composition were investigated in three sediment cores Lake Michigan (LM). Two collected from Green Bay, a region heavily impacted by contamination one core an offshore of LM absent direct point source Hg. Historical trends influxes suggest increased deposition began the 1890s Bay early 1800’s LM. Recently deposited reflecting more anthropogenic influence shows similar δ202 values (-1.0 to -0.5‰) for all however, deep sediments,...
Abstract In the past decades, China has experienced substantial economic growth and industrialization. However, effects of vast development on Hg input to nearby oceans are still unclear. this study, influx isotopic compositions in four 210 Pb‐dated sediment cores were examined investigate changes deposition marginal seas off over a century. Nearshore had higher influxes than offshore cores. Increases started since 1950s, which coincides with China's development. Dramatic historical...
Mercury concentrations in the Laurentian Great Lakes waters are among lowest reported literature, while game fish approach consumption advisory limits, particularly Superior, Huron, and Michigan, indicating efficient methylmercury transfer from water to fish. To determine if increased efficiency is evident within lower food web, we measured (2010–2018) mercury dissolved organic carbon (DOC) water, size-sieved seston, dietary tracers (carbon nitrogen isotope ratios), phytoplankton...
This study describes and validates a new method for extracting perfluoroalkyl polyfluoroalkyl substances (PFAS) from whole-body fish tissue, demonstrates that freeze-dry preservation of tissue conserves bioaccumulative PFAS, details demonstration on Lake Michigan fish. While filets are more commonly analyzed their significance to human health, whole useful determine ecological impacts, but published methods such as EPA 1633 do not produce reliable results this challenging matrix. Here we...
Increased lake eutrophication, influenced by changing climate and land use, alters aquatic cycling bioaccumulation of mercury (Hg). Additionally, seasonally dynamic circulation plankton community composition can confound our ability to predict changes in biological Hg concentrations sources. To assess temporal variation, we examined seasonal total (THg) methylmercury (MeHg) stable isotope values seston, waters, sediments, fish from two adjacent urban eutrophic lakes Madison, Wisconsin. In...
Abstract With the 2011 promulgation of Mercury and Air Toxics Standards by U.S. Environmental Protection Agency, successful negotiation United Nations Environment Program Minamata Convention, emissions mercury (Hg) have declined in States. While declines atmospheric Hg concentrations North America are encouraging, linking to changing domestic global source portfolios remains challenging. To address these research gaps, Geological Survey initiated first national‐scale effort establish a...
Recent spread of invasive mussels in Lake Michigan has altered primary productivity the nearshore zone, resulting proliferation filamentous benthic green algae (Cladophora glomerata). In areas dense Cladophora and quagga mussel (Dreissena bugensis) assemblages, as well regions where sloughed accumulates, methylmercury (MeHg) production is enhanced. A shoreline transect from a river mouth through waters overlying Cladophora/quagga-rich zones showed that aqueous MeHg concentrations increased,...
Through stable isotope measurements of total mercury (HgT), identification crucial processes and transformations affecting different sources (Hg) has become possible. However, attempting to use HgT isotopes track bioaccumulation Hg among food web compartments can be challenging, if not impossible, when tissues have varying methylmercury (MeHg) contents. We measured MeHg ratios within the lower Fox River examine how these values differed across in biota were influenced by legacy...