Sarah E Janssen
Sarah Janssen is an isotope geochemist working in the M3 Research Lab (MRL) located within the Upper Midwest Water Science Center.
She has a PhD in environmental chemistry from Rutgers University and a bachelor’s in chemistry from
University of the Sciences in Philadelphia. Her work focuses on the application of stable isotope techniques for understanding sources and transformations of mercury (Hg) in the environment. Her research interests include Hg cycling in contaminated ecosystems, the investigation of microbial Hg transformations using stable isotopes, and development of analytical methods to improve Hg isotope measurements.
Current Projects
- Mercury Cycling and Source Identification in the St Louis River Estuary MN/WI (collaboration with US EPA and Minnesota Pollution Control Agency)
- Mercury Isotope Fractionation during Microbial Uptake and Transformations of Hg (collaboration with Rutgers University and University of Ottawa)
- Method Development for the Pre-concentration of Waters and Low Concentration Environmental Samples for Mercury Isotopic Analysis
Education and Certifications
Ph.D. 2016, Environmental Chemistry, Rutgers University, New Brunswick, NJ
B.S. 2011, Chemistry, University of the Sciences, Philadelphia, PA
Science and Products
Filter Total Items: 38
Isotopic Examination of Mercury Methylation and Demethylation Rates in Yellowstone National Park Thermal Features Isotopic Examination of Mercury Methylation and Demethylation Rates in Yellowstone National Park Thermal Features
Data in this data release were obtained for water samples collected under Yellowstone National Park Research Permit YELL-05194 in 2017 through the Integrated Yellowstone Studies Project funded by the Mineral Resources Program. Isotope-spiked incubations were carried out to determine methylation and demethylation potential for Frying Pan spring, Crystal Sister East, Crystal Sister West...
Yellowstone Thermal Feature Mercury and Methylmercury Characterization Yellowstone Thermal Feature Mercury and Methylmercury Characterization
Data in this data release were obtained from water samples collected under Yellowstone National Park (YNP) Research Permit YELL-05194 in 2017, 2019, and 2020 through the Integrated Yellowstone Studies Project funded by the Mineral Resources Program. These samples were used to assess mercury cycling within YNP. Water samples were analyzed for total mercury and methylmercury, the...
Mercury source identification in the Mobile and Tombigbee Rivers Mercury source identification in the Mobile and Tombigbee Rivers
This dataset details mercury concentrations and mercury stable isotope values collected as part of an environmental mercury assessment encompassing the Mobile and Tombigbee Rivers as well as two U.S. Environmental Protection Agency Superfund sites. The Tensaw River was also sampled as part of this study as a reference site, absent of mercury contamination. As a part of this survey...
Mercury and Methylmercury Stable Isotope Measurements in Giant Petrels Mercury and Methylmercury Stable Isotope Measurements in Giant Petrels
Methylmercury (MeHg) and total mercury (HgT) stable isotope measurements were made by the USGS Mercury Research Lab (MRL) in different organs on the Giant Petrels (Macronectes spp.) to examine internal mercury cycling in these seabirds. These data were collected as a compliment to x-ray spectroscopy measurements made by the University of Grenoble, France. The tissues and feathers of the...
Chemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 3.0, November 2023) Chemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 3.0, November 2023)
This dataset includes laboratory analyses of surface water samples and sediment trap material collected from (1) locations upstream, downstream, and within the Hells Canyon Complex (Idaho, Oregon) of the Snake River, (2) tributaries of the Snake River, and (3) two reservoirs near Boise, Idaho, from 2014 to 2021. The study area spans approximately 232 river miles of the Snake River and...
Mercury Concentrations and Mercury Isotopes in Salmonid fishes from the Snake River and tributaries in Idaho and Oregon, 2015 and 2019 (ver. 2.0, February 2021) Mercury Concentrations and Mercury Isotopes in Salmonid fishes from the Snake River and tributaries in Idaho and Oregon, 2015 and 2019 (ver. 2.0, February 2021)
Comma-separated values (.csv) file containing data related to mercury in Salmonid fishes collected from the Snake River and tributaries, Idaho and Oregon.
Mercury concentrations and isotopic compositions in biota and sediments from the Hannibal Pool of the Ohio River Mercury concentrations and isotopic compositions in biota and sediments from the Hannibal Pool of the Ohio River
The Hannibal Pool of the Ohio River is heavily industrialized and receives direct effluent discharges from coal power plants, chlor-alkali plants, and sewage treatment facilities. Mercury (Hg) is a contaminant of concern due to the risk of bioaccumulation at wildlife refuges also located within this region. Mercury concentrations and isotopes compositions were measured to assess the...
Mercury Concentrations and Isotopic Compositions in Sediment Cores from North American Lakes (Alaska, Minnesota, and Newfoundland) Mercury Concentrations and Isotopic Compositions in Sediment Cores from North American Lakes (Alaska, Minnesota, and Newfoundland)
Mercury isotope measurements were made across nine sediments cores from remote North American lakes to examine changes in the Hg isotope profiles. The lakes spanned regions of Alaska, Minnesota, and Newfoundland as well as a range of temperate to arctic climates. This data describes the natural record of mass dependent (MDF) and mass independent (MIF) Hg isotope fractionation related to...
Isolation of Methylmercury Using Distillation and Anion-Exchange Chromatography for Isotopic Analyses in Natural Matrices Data Release Isolation of Methylmercury Using Distillation and Anion-Exchange Chromatography for Isotopic Analyses in Natural Matrices Data Release
This dataset consists of concentration and isotopic data for a method designed to isolate and analyze methylmercury. Several matrices (lab-based, and natural) were tested to ensure that the method was capable of recovering methylmercury amendments. Additionally, natural matrices (plankton and sediment) with ambient methylmercury were also analyzed to ensure that the method could be...
Gruber's Grove Bay Mercury Site Assessment Gruber's Grove Bay Mercury Site Assessment
Mercury (Hg) concentrations and isotopic compositions were collected in sediments, soils, and suspended particulate matter from Gruber's Grove Bay (GGB) and upstream reference sites to inform future remedial efforts. The highest concentrations and isotopic signatures were observed in soils collected from historic water settling ponds from the Badger Army Ammunition Plant (BAAP)...
Regional Trends of Isotopic Composition in Total Gaseous Mercury Across the United States Regional Trends of Isotopic Composition in Total Gaseous Mercury Across the United States
The dataset presented here represents the concentrations and stable isotopic composition of gaseous mercury (Hg) for 31 sites across the United States. This national-scale monitoring effort was performed by the National Atmospheric Deposition Program (NADP) and the USGS over a two-year period (March 2016 - May 2018). The network includes a highly diverse set of sites ranging from remote...
Stable Mercury Isotopic Analyses in Natural Matrices via Rapid Pre-Concentration Method Stable Mercury Isotopic Analyses in Natural Matrices via Rapid Pre-Concentration Method
This data relates to the development of a modified pre-concentration method for mercury (Hg) stable isotope measurements that uses chemical Hg reduction and gold trap amalgamation followed by semi-rapid thermal desorption (less than 1 hour) and chemical trapping in a novel oxidizing solution. The thermal desorption method was demonstrated to perform adequately on multiple trapping...
Filter Total Items: 50
Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs
The transfer of aquatic contaminants, including mercury (Hg), to terrestrial food webs is an often-overlooked exposure pathway to terrestrial animals. While research has implemented the use of shoreline spiders to assess aquatic to terrestrial Hg transfer, it is unclear whether Hg sources, estimated from isotope ratios, can be successfully resolved to inform site assessments and remedy
Authors
Sarah E. Janssen, Christopher James Kotalik, Collin A. Eagles-Smith, Gale B. Beaubien, Joel C. Hoffman, Greg Peterson, Marc A. Mills, David Walters
Contrasting mercury contamination scenarios and site susceptibilities confound fish mercury burdens in Suriname, South America Contrasting mercury contamination scenarios and site susceptibilities confound fish mercury burdens in Suriname, South America
In Suriname, mercury (Hg) use has recently increased because of gold mining, which has put fish-reliant communities (e.g., Indigenous and Tribal) at risk of enhanced Hg exposure through the riverine fish these communities consume. To quantify how the magnitude of these risks change according to location and time, we measured total mercury (HgT) in fish at sites downstream and upstream of...
Authors
Arioene Vreedzaam, Paul Ouboter, Ashna D. Hindori-Mohangoo, Ryan F. Lepak, Samantha L. Rumschlag, Sarah E. Janssen, Gwen Landburg, Arti Shankar, Wilco Zijlmans, Maureen Y. Lichtveld, Jeffrey K. Wickliffe
National-scale assessment of total gaseous mercury isotopes across the United States National-scale assessment of total gaseous mercury isotopes across the United States
With the 2011 promulgation of the Mercury and Air Toxics Standards by the U.S. Environmental Protection Agency, and the successful negotiation by the United Nations Environment Program of the Minamata Convention, emissions of mercury (Hg) have declined in the United States. While the declines in atmospheric Hg concentrations in North America are encouraging, linking the declines to...
Authors
Michael T. Tate, Sarah E. Janssen, Ryan F. Lepak, Laura Elizabeth Flucke, David P. Krabbenhoft
Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish
Ecosystems downstream of mercury (Hg) contaminated sites can be impacted by both localized releases as well as Hg deposited to the watershed from atmospheric transport. Identifying the source of Hg in water, sediment, and fish downstream of contaminated sites is important for determining the effectiveness of source-control remediation actions. This study uses measurements of Hg stable...
Authors
Chris S. Eckley, Collin A. Eagles-Smith, Todd P Luxton, Joel C. Hoffman, Sarah E. Janssen
Tracing the sources and depositional history of mercury to coastal northeastern U.S. lakes Tracing the sources and depositional history of mercury to coastal northeastern U.S. lakes
Mercury (Hg) deposition was reconstructed in sediment cores from lakes in two coastal U.S. National Parks: Acadia National Park (ANP) and Cape Cod National Seashore (CCNS), to fill an important spatial gap in Hg deposition records and to explore changing sources of Hg and processes affecting Hg accumulation in these coastal sites. Recent Hg deposition chronology was assessed using (1) a...
Authors
Vivien F. Taylor, Joshua D. Landis, Sarah E. Janssen
Elevated mercury concentrations and isotope signatures (N, C, Hg) in yellowfin tuna (Thunnus albacares) from the Galápagos Marine Reserve and waters off Ecuador Elevated mercury concentrations and isotope signatures (N, C, Hg) in yellowfin tuna (Thunnus albacares) from the Galápagos Marine Reserve and waters off Ecuador
We examined how dietary factors recorded by C and N influence Hg uptake in 347 individuals of yellowfin tuna (Thunnus albacares), an important subsistence resource from the Galápagos Marine Reserve (GMR) and the Ecuadorian mainland coast (EMC) in 2015-2016. We found no differences in total Hg (THg) measured in red muscle between the two regions and no seasonal differences, likely due to...
Authors
Laia Munoz-Abril, Carlos A Valle, Juan Jose Alava, Sarah E. Janssen, Elsie M. Sunderland, Francisco Rubianes-Landazuri, Steven D Emslie
Assessment of mercury in sediments and waters of Grubers Grove Bay, Wisconsin Assessment of mercury in sediments and waters of Grubers Grove Bay, Wisconsin
Mercury is a global contaminant that can be detrimental to wildlife and human health. Anthropogenic emissions and point sources are primarily responsible for elevated mercury concentrations in sediments and waters. Mercury can physically move and chemically transform in the environment, resulting in biomagnification of mercury, in the form of methylmercury, in the food web and causing...
Authors
Evan J. Routhier, Sarah E. Janssen, Michael T. Tate, Jacob M. Ogorek, John F. DeWild, David P. Krabbenhoft
Decadal trends of mercury cycling and bioaccumulation within Everglades National Park Decadal trends of mercury cycling and bioaccumulation within Everglades National Park
Mercury (Hg) contamination has been a persistent concern in the Florida Everglades for over three decades due to elevated atmospheric deposition and the system's propensity for methylation and rapid bioaccumulation. Given declines in atmospheric Hg concentrations in the conterminous United States and efforts to mitigate nutrient release to the greater Everglades ecosystem, it was vital...
Authors
Sarah E. Janssen, Michael T. Tate, Brett Poulin, David P. Krabbenhoft, John F DeWild, Jacob M. Ogorek, Matthew S. Varonka, William H. Orem, Jeffrey D Kline
Methylmercury stable isotopes: New insights on assessing aquatic food web bioaccumulation in legacy impacted regions Methylmercury stable isotopes: New insights on assessing aquatic food web bioaccumulation in legacy impacted regions
Through stable isotope measurements of total mercury (HgT), identification of crucial processes and transformations affecting different sources of mercury (Hg) has become possible. However, attempting to use HgT stable isotopes to track bioaccumulation of Hg sources among different food web compartments can be challenging, if not impossible, when tissues have varying methylmercury (MeHg)...
Authors
Tylor Rosera, Sarah E. Janssen, Michael T. Tate, Ryan F. Lepak, Jacob M. Ogorek, John F. DeWild, David P. Krabbenhoft, James P. Hurley
Using carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout Using carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout
Lake trout (Salvelinus namaycush), collected from 13 remote lakes located in southwestern Alaska, were analyzed for carbon, nitrogen, and mercury (Hg) stable isotope values to assess the importance of migrating oceanic salmon, volcanic activity, and atmospheric deposition to fish Hg burden. Methylmercury (MeHg) bioaccumulation in phytoplankton (5.0–6.9 kg L–1) was also measured to...
Authors
Ryan F. Lepak, Jacob M. Ogorek, Krista K. Bartz, Sarah E. Janssen, Michael T. Tate, Yin Runsheng, James P. Hurley, Daniel B. Young, Collin A. Eagles-Smith, David P. Krabbenhoft
Response to comment on “Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science”: Principles and limitations of source tracing and process tracing with stable isot Response to comment on “Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science”: Principles and limitations of source tracing and process tracing with stable isot
No abstract available.
Authors
Alain Manceau, Romain Brossier, Sarah E. Janssen, Brett Poulin
Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science
A prerequisite for environmental and toxicological applications of mercury (Hg) stable isotopes in wildlife and humans is quantifying the isotopic fractionation of biological reactions. Here, we measured stable Hg isotope values of relevant tissues of giant petrels (Macronectes spp.). Isotopic data were interpreted with published HR-XANES spectroscopic data that document a stepwise...
Authors
Alain Manceau, Romain Brossier, Sarah E. Janssen, Tylor Rosera, David P. Krabbenhoft, Yves Cherel, Paco Bustamante, Brett Poulin
Non-USGS Publications**
Janssen, S.E.; Johnson, M.W.; Blum, J.D.; Barkay, T.; Reinfelder, J.R., Separation of monomethylmercury from estuarine sediments for mercury isotope analysis. Chemical Geology 2015
Janssen, S.E.; Schaefer, J.K.; Barkay, T.; Reinfelder, J.R. Fractionation of mercury stable isotopes during microbial methylmercury production in pure culture. Environ. Sci. Technol. 2016
Lloyd, N.; Janssen, S.E.; Reinfelder J.R.; Barkay, T., Exposure to mercury selects for antibiotic resistance in Fundulus heteroclitus gut microbiome, Current Microbiology, 2016
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 38
Isotopic Examination of Mercury Methylation and Demethylation Rates in Yellowstone National Park Thermal Features Isotopic Examination of Mercury Methylation and Demethylation Rates in Yellowstone National Park Thermal Features
Data in this data release were obtained for water samples collected under Yellowstone National Park Research Permit YELL-05194 in 2017 through the Integrated Yellowstone Studies Project funded by the Mineral Resources Program. Isotope-spiked incubations were carried out to determine methylation and demethylation potential for Frying Pan spring, Crystal Sister East, Crystal Sister West...
Yellowstone Thermal Feature Mercury and Methylmercury Characterization Yellowstone Thermal Feature Mercury and Methylmercury Characterization
Data in this data release were obtained from water samples collected under Yellowstone National Park (YNP) Research Permit YELL-05194 in 2017, 2019, and 2020 through the Integrated Yellowstone Studies Project funded by the Mineral Resources Program. These samples were used to assess mercury cycling within YNP. Water samples were analyzed for total mercury and methylmercury, the...
Mercury source identification in the Mobile and Tombigbee Rivers Mercury source identification in the Mobile and Tombigbee Rivers
This dataset details mercury concentrations and mercury stable isotope values collected as part of an environmental mercury assessment encompassing the Mobile and Tombigbee Rivers as well as two U.S. Environmental Protection Agency Superfund sites. The Tensaw River was also sampled as part of this study as a reference site, absent of mercury contamination. As a part of this survey...
Mercury and Methylmercury Stable Isotope Measurements in Giant Petrels Mercury and Methylmercury Stable Isotope Measurements in Giant Petrels
Methylmercury (MeHg) and total mercury (HgT) stable isotope measurements were made by the USGS Mercury Research Lab (MRL) in different organs on the Giant Petrels (Macronectes spp.) to examine internal mercury cycling in these seabirds. These data were collected as a compliment to x-ray spectroscopy measurements made by the University of Grenoble, France. The tissues and feathers of the...
Chemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 3.0, November 2023) Chemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 3.0, November 2023)
This dataset includes laboratory analyses of surface water samples and sediment trap material collected from (1) locations upstream, downstream, and within the Hells Canyon Complex (Idaho, Oregon) of the Snake River, (2) tributaries of the Snake River, and (3) two reservoirs near Boise, Idaho, from 2014 to 2021. The study area spans approximately 232 river miles of the Snake River and...
Mercury Concentrations and Mercury Isotopes in Salmonid fishes from the Snake River and tributaries in Idaho and Oregon, 2015 and 2019 (ver. 2.0, February 2021) Mercury Concentrations and Mercury Isotopes in Salmonid fishes from the Snake River and tributaries in Idaho and Oregon, 2015 and 2019 (ver. 2.0, February 2021)
Comma-separated values (.csv) file containing data related to mercury in Salmonid fishes collected from the Snake River and tributaries, Idaho and Oregon.
Mercury concentrations and isotopic compositions in biota and sediments from the Hannibal Pool of the Ohio River Mercury concentrations and isotopic compositions in biota and sediments from the Hannibal Pool of the Ohio River
The Hannibal Pool of the Ohio River is heavily industrialized and receives direct effluent discharges from coal power plants, chlor-alkali plants, and sewage treatment facilities. Mercury (Hg) is a contaminant of concern due to the risk of bioaccumulation at wildlife refuges also located within this region. Mercury concentrations and isotopes compositions were measured to assess the...
Mercury Concentrations and Isotopic Compositions in Sediment Cores from North American Lakes (Alaska, Minnesota, and Newfoundland) Mercury Concentrations and Isotopic Compositions in Sediment Cores from North American Lakes (Alaska, Minnesota, and Newfoundland)
Mercury isotope measurements were made across nine sediments cores from remote North American lakes to examine changes in the Hg isotope profiles. The lakes spanned regions of Alaska, Minnesota, and Newfoundland as well as a range of temperate to arctic climates. This data describes the natural record of mass dependent (MDF) and mass independent (MIF) Hg isotope fractionation related to...
Isolation of Methylmercury Using Distillation and Anion-Exchange Chromatography for Isotopic Analyses in Natural Matrices Data Release Isolation of Methylmercury Using Distillation and Anion-Exchange Chromatography for Isotopic Analyses in Natural Matrices Data Release
This dataset consists of concentration and isotopic data for a method designed to isolate and analyze methylmercury. Several matrices (lab-based, and natural) were tested to ensure that the method was capable of recovering methylmercury amendments. Additionally, natural matrices (plankton and sediment) with ambient methylmercury were also analyzed to ensure that the method could be...
Gruber's Grove Bay Mercury Site Assessment Gruber's Grove Bay Mercury Site Assessment
Mercury (Hg) concentrations and isotopic compositions were collected in sediments, soils, and suspended particulate matter from Gruber's Grove Bay (GGB) and upstream reference sites to inform future remedial efforts. The highest concentrations and isotopic signatures were observed in soils collected from historic water settling ponds from the Badger Army Ammunition Plant (BAAP)...
Regional Trends of Isotopic Composition in Total Gaseous Mercury Across the United States Regional Trends of Isotopic Composition in Total Gaseous Mercury Across the United States
The dataset presented here represents the concentrations and stable isotopic composition of gaseous mercury (Hg) for 31 sites across the United States. This national-scale monitoring effort was performed by the National Atmospheric Deposition Program (NADP) and the USGS over a two-year period (March 2016 - May 2018). The network includes a highly diverse set of sites ranging from remote...
Stable Mercury Isotopic Analyses in Natural Matrices via Rapid Pre-Concentration Method Stable Mercury Isotopic Analyses in Natural Matrices via Rapid Pre-Concentration Method
This data relates to the development of a modified pre-concentration method for mercury (Hg) stable isotope measurements that uses chemical Hg reduction and gold trap amalgamation followed by semi-rapid thermal desorption (less than 1 hour) and chemical trapping in a novel oxidizing solution. The thermal desorption method was demonstrated to perform adequately on multiple trapping...
Filter Total Items: 50
Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs
The transfer of aquatic contaminants, including mercury (Hg), to terrestrial food webs is an often-overlooked exposure pathway to terrestrial animals. While research has implemented the use of shoreline spiders to assess aquatic to terrestrial Hg transfer, it is unclear whether Hg sources, estimated from isotope ratios, can be successfully resolved to inform site assessments and remedy
Authors
Sarah E. Janssen, Christopher James Kotalik, Collin A. Eagles-Smith, Gale B. Beaubien, Joel C. Hoffman, Greg Peterson, Marc A. Mills, David Walters
Contrasting mercury contamination scenarios and site susceptibilities confound fish mercury burdens in Suriname, South America Contrasting mercury contamination scenarios and site susceptibilities confound fish mercury burdens in Suriname, South America
In Suriname, mercury (Hg) use has recently increased because of gold mining, which has put fish-reliant communities (e.g., Indigenous and Tribal) at risk of enhanced Hg exposure through the riverine fish these communities consume. To quantify how the magnitude of these risks change according to location and time, we measured total mercury (HgT) in fish at sites downstream and upstream of...
Authors
Arioene Vreedzaam, Paul Ouboter, Ashna D. Hindori-Mohangoo, Ryan F. Lepak, Samantha L. Rumschlag, Sarah E. Janssen, Gwen Landburg, Arti Shankar, Wilco Zijlmans, Maureen Y. Lichtveld, Jeffrey K. Wickliffe
National-scale assessment of total gaseous mercury isotopes across the United States National-scale assessment of total gaseous mercury isotopes across the United States
With the 2011 promulgation of the Mercury and Air Toxics Standards by the U.S. Environmental Protection Agency, and the successful negotiation by the United Nations Environment Program of the Minamata Convention, emissions of mercury (Hg) have declined in the United States. While the declines in atmospheric Hg concentrations in North America are encouraging, linking the declines to...
Authors
Michael T. Tate, Sarah E. Janssen, Ryan F. Lepak, Laura Elizabeth Flucke, David P. Krabbenhoft
Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish
Ecosystems downstream of mercury (Hg) contaminated sites can be impacted by both localized releases as well as Hg deposited to the watershed from atmospheric transport. Identifying the source of Hg in water, sediment, and fish downstream of contaminated sites is important for determining the effectiveness of source-control remediation actions. This study uses measurements of Hg stable...
Authors
Chris S. Eckley, Collin A. Eagles-Smith, Todd P Luxton, Joel C. Hoffman, Sarah E. Janssen
Tracing the sources and depositional history of mercury to coastal northeastern U.S. lakes Tracing the sources and depositional history of mercury to coastal northeastern U.S. lakes
Mercury (Hg) deposition was reconstructed in sediment cores from lakes in two coastal U.S. National Parks: Acadia National Park (ANP) and Cape Cod National Seashore (CCNS), to fill an important spatial gap in Hg deposition records and to explore changing sources of Hg and processes affecting Hg accumulation in these coastal sites. Recent Hg deposition chronology was assessed using (1) a...
Authors
Vivien F. Taylor, Joshua D. Landis, Sarah E. Janssen
Elevated mercury concentrations and isotope signatures (N, C, Hg) in yellowfin tuna (Thunnus albacares) from the Galápagos Marine Reserve and waters off Ecuador Elevated mercury concentrations and isotope signatures (N, C, Hg) in yellowfin tuna (Thunnus albacares) from the Galápagos Marine Reserve and waters off Ecuador
We examined how dietary factors recorded by C and N influence Hg uptake in 347 individuals of yellowfin tuna (Thunnus albacares), an important subsistence resource from the Galápagos Marine Reserve (GMR) and the Ecuadorian mainland coast (EMC) in 2015-2016. We found no differences in total Hg (THg) measured in red muscle between the two regions and no seasonal differences, likely due to...
Authors
Laia Munoz-Abril, Carlos A Valle, Juan Jose Alava, Sarah E. Janssen, Elsie M. Sunderland, Francisco Rubianes-Landazuri, Steven D Emslie
Assessment of mercury in sediments and waters of Grubers Grove Bay, Wisconsin Assessment of mercury in sediments and waters of Grubers Grove Bay, Wisconsin
Mercury is a global contaminant that can be detrimental to wildlife and human health. Anthropogenic emissions and point sources are primarily responsible for elevated mercury concentrations in sediments and waters. Mercury can physically move and chemically transform in the environment, resulting in biomagnification of mercury, in the form of methylmercury, in the food web and causing...
Authors
Evan J. Routhier, Sarah E. Janssen, Michael T. Tate, Jacob M. Ogorek, John F. DeWild, David P. Krabbenhoft
Decadal trends of mercury cycling and bioaccumulation within Everglades National Park Decadal trends of mercury cycling and bioaccumulation within Everglades National Park
Mercury (Hg) contamination has been a persistent concern in the Florida Everglades for over three decades due to elevated atmospheric deposition and the system's propensity for methylation and rapid bioaccumulation. Given declines in atmospheric Hg concentrations in the conterminous United States and efforts to mitigate nutrient release to the greater Everglades ecosystem, it was vital...
Authors
Sarah E. Janssen, Michael T. Tate, Brett Poulin, David P. Krabbenhoft, John F DeWild, Jacob M. Ogorek, Matthew S. Varonka, William H. Orem, Jeffrey D Kline
Methylmercury stable isotopes: New insights on assessing aquatic food web bioaccumulation in legacy impacted regions Methylmercury stable isotopes: New insights on assessing aquatic food web bioaccumulation in legacy impacted regions
Through stable isotope measurements of total mercury (HgT), identification of crucial processes and transformations affecting different sources of mercury (Hg) has become possible. However, attempting to use HgT stable isotopes to track bioaccumulation of Hg sources among different food web compartments can be challenging, if not impossible, when tissues have varying methylmercury (MeHg)...
Authors
Tylor Rosera, Sarah E. Janssen, Michael T. Tate, Ryan F. Lepak, Jacob M. Ogorek, John F. DeWild, David P. Krabbenhoft, James P. Hurley
Using carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout Using carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout
Lake trout (Salvelinus namaycush), collected from 13 remote lakes located in southwestern Alaska, were analyzed for carbon, nitrogen, and mercury (Hg) stable isotope values to assess the importance of migrating oceanic salmon, volcanic activity, and atmospheric deposition to fish Hg burden. Methylmercury (MeHg) bioaccumulation in phytoplankton (5.0–6.9 kg L–1) was also measured to...
Authors
Ryan F. Lepak, Jacob M. Ogorek, Krista K. Bartz, Sarah E. Janssen, Michael T. Tate, Yin Runsheng, James P. Hurley, Daniel B. Young, Collin A. Eagles-Smith, David P. Krabbenhoft
Response to comment on “Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science”: Principles and limitations of source tracing and process tracing with stable isot Response to comment on “Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science”: Principles and limitations of source tracing and process tracing with stable isot
No abstract available.
Authors
Alain Manceau, Romain Brossier, Sarah E. Janssen, Brett Poulin
Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science
A prerequisite for environmental and toxicological applications of mercury (Hg) stable isotopes in wildlife and humans is quantifying the isotopic fractionation of biological reactions. Here, we measured stable Hg isotope values of relevant tissues of giant petrels (Macronectes spp.). Isotopic data were interpreted with published HR-XANES spectroscopic data that document a stepwise...
Authors
Alain Manceau, Romain Brossier, Sarah E. Janssen, Tylor Rosera, David P. Krabbenhoft, Yves Cherel, Paco Bustamante, Brett Poulin
Non-USGS Publications**
Janssen, S.E.; Johnson, M.W.; Blum, J.D.; Barkay, T.; Reinfelder, J.R., Separation of monomethylmercury from estuarine sediments for mercury isotope analysis. Chemical Geology 2015
Janssen, S.E.; Schaefer, J.K.; Barkay, T.; Reinfelder, J.R. Fractionation of mercury stable isotopes during microbial methylmercury production in pure culture. Environ. Sci. Technol. 2016
Lloyd, N.; Janssen, S.E.; Reinfelder J.R.; Barkay, T., Exposure to mercury selects for antibiotic resistance in Fundulus heteroclitus gut microbiome, Current Microbiology, 2016
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.