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
Sarah E Janssen
Biography
Sarah Janssen is an isotope geochemist working in the Mercury 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.
Education
Ph.D. 2016, Environmental Chemistry, Rutgers University, New Brunswick, NJ
B.S. 2011, Chemistry, University of the Sciences, Philadelphia, PA
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
Science and Products
Year Published: 2019
Tracking legacy mercury in the Hackensack River Estuary using mercury stable isotopes
Spatial redistribution of legacy mercury (Hg) contamination in the Hackensack River estuary (New Jersey, USA) was evaluated using mercury stable isotopes. Total Hg varied from 0.06 to 3.8 µg g-1 in sediment from the tidal Hackensack River and from 15 to 154 µg g-1 near historically contaminated sites in upper Berry's Creek, a tributary of the...
Reinfelder, John R; Janssen, Sarah E.
Year Published: 2019
Rapid pre-concentration of mercury in solids and water for isotopic analysis
The precise quantification of mercury (Hg) stable isotope compositions in low concentration or dilute samples poses analytical challenges due to Hg mass limitations. Common Hg pre-concentration procedures require extended processing times, making rapid Hg stable isotope measurements challenging. Here we present a modified pre-...
Janssen, Sarah E.; Lepak, Ryan F.; Tate, Michael T.; Ogorek, Jacob M.; DeWild, John F.; Babiarz, Christopher L.; Hurley, James P.; Krabbenhoft, David P.
Year Published: 2019
Mercury isotopes reveal an ontogenetic shift in habitat use by walleye in lower Green Bay of Lake Michigan
In general, fish residing in rivers differ from fish residing in lakes in their mercury (Hg) isotope ratios. Specifically, fish residing in lakes typically show enriched values for the isotope ratios of δ202Hg (mass-dependent fractionation of isotope 202Hg) and Δ199Hg (mass-independent fractionation of isotope 199Hg) compared with fish...
Madenjian, Charles P.; Janssen, Sarah E.; Lepak, Ryan F.; Ogorek, Jacob M.; Rosera, Tylor J.; DeWild, John F.; Krabbenhoft, David P.; Cogswell, Stewart F.; Holey, Mark E.
Year Published: 2018
Factors affecting mercury stable isotopic distribution in piscivorous fish of the Laurentian Great Lakes
Identifying the sources of methylmercury (MeHg) and tracing the transformations of mercury (Hg) in the aquatic food web are important components of effective strategies for managing current and legacy Hg sources. In our previous work, we measured stable isotopes of Hg (δ202Hg, Δ199Hg, and Δ200Hg) in the Laurentian Great Lakes and estimated source...
Janssen, Sarah E.; Yin, Runsheng; Ogorek, Jacob M.; DeWild, John F.; Tate, Michael T.; Holsen, Thomas M.; Hurley, James P.; Lepak, Ryan F.; Janssen, Sarah E.; Yin, Runsheng; Ogorek, Jacob M.; Krabbenhoft, David P.; DeWild, John F.; Tate, Michael T.; Holsen, Thomas M.; Hurley, James P.Pre-USGS Publications
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