John F DeWild
Science and Products
The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin
Past industrial use and subsequent release of mercury (Hg) into the environment have resulted in severe cases of legacy contamination that still influence contemporary Hg levels in biota. While the bioaccumulation of legacy Hg is commonly assessed via concentration measurements within fish tissue, this practice becomes difficult in regions of high...
Janssen, Sarah E.; Tate, Michael T.; Krabbenhoft, David P.; DeWild, John F.; Ogorek, Jacob M.; Babiarz, Christopher L.; Sowers, Anthony; Tuttle, Peter L. Isolation of methylmercury using distillation and anion-exchange chromatography for isotopic analyses in natural matrices
The development of mercury (Hg) stable isotope measurements has enhanced the study of Hg sources and transformations in the environment. As a result of the mixing of inorganic Hg (iHg) and methylmercury (MeHg) species within organisms of the aquatic food web, understanding species-specific Hg stable isotopic compositions is of significant...
Rosera, Tylor; Janssen, Sarah E.; Tate, Michael T.; Lepak, Ryan F.; Ogorek, Jacob M.; DeWild, John F.; Babiarz, Christopher L.; Krabbenhoft, David P.; Hurley, James P. Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan
To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources....
Lepak, Ryan F.; Hoffman, Joel C.; Janssen, Sarah E.; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Tate, Michael T.; Babiarz, Christopher L.; Yin, Runsheng; Murphy, Elizabeth W; Engstrom, Daniel R; Hurley, James P. Chemical and physical controls on mercury source signatures in stream fish from the northeastern United States
Streams in the northeastern U.S. receive mercury (Hg) in varying proportions from atmospheric deposition and legacy point sources, making it difficult to attribute shifts in fish concentrations directly back to changes in Hg source management. Mercury stable isotope tracers were utilized to relate sources of Hg to co-located fish and bed sediments...
Janssen, Sarah E.; Riva-Murray, Karen; DeWild, John F.; Ogorek, Jacob M.; Tate, Michael T.; Van Metre, Peter C.; Krabbenhoft, David P.; Coles, James F. 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. 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.
Tidal flushing of mercury from the Bremerton Naval Complex through the PSNS015 stormwater drain system to Sinclair Inlet, Kitsap County, Washington, 2011 -12
The sediments of Sinclair Inlet, in Puget Sound, Washington, have elevated levels of contaminants including mercury. The Bremerton Naval Complex is adjacent to Sinclair Inlet, and has known areas of historical soil mercury contamination. The U.S. Geological Survey, in cooperation with the U.S. Navy, has been investigating the potential for mercury...
Conn, Kathleen E.; Paulson, Anthony J.; Dinicola, Richard S.; DeWild, John F. Ratio of mercury concentration to PCB concentration varies with sex of white sucker (Catostomus commersonii)
The whole-fish total mercury (Hg) concentrations were determined in 25 mature female and 26 mature male white suckers (Catostomus commersonii) caught during their spawning run in the Kewaunee River, a tributary to Lake Michigan. The age of each fish was estimated using thin-sectioned otoliths, and total length (TL) and weight were determined for...
Madenjian, Charles P.; Stevens, Andrew L.; Stapanian, Martin A.; Krabbenhoft, David P.; DeWild, John F.; Ogorek, Jacob M.; Edwards, William H.; Ogilvie, Lynn M.; McIntyre, Peter B.
Mercury methylation and bioaccumulation in Sinclair Inlet, Kitsap County, Washington
The U.S. Geological Survey evaluated the transformation of mercury to bioavailable methylmercury in Sinclair Inlet, Kitsap County, Washington, and assessed the effect of the transformation processes on the mercury burden in marine organisms and sediment. In August 2008, samples of sediment, water, and biota from six sites in Sinclair Inlet and...
Paulson, A.J.; Marvin-DiPasquale, M.C.; Moran, P.W.; DeWild, J.F.; Stewart, A.R.; Toft, J.; Agee, J.L.; Kakouros, E.; Kieu, Le H.; Carter, B.; Sheibley, R.W.; Cordell, J.; Krabbenhoft, David P. 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; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Tate, Michael T.; Holsen, Thomas M.; Hurley, James P. Permafrost stores a globally significant amount of mercury
Changing climate in northern regions is causing permafrost to thaw with major implications for the global mercury (Hg) cycle. We estimated Hg in permafrost regions based on in situ measurements of sediment total mercury (STHg), soil organic carbon (SOC), and the Hg to carbon ratio (RHgC) combined with maps of soil carbon. We measured a median STHg...
Schuster, Paul F.; Schaefer, Kevin; Aiken, George R.; Antweiler, Ronald C.; DeWild, John F.; Gryziec, Joshua D.; Gusmeroli, Alessio; Hugelius, Gustaf; Jafarov, Elchin E.; Krabbenhoft, David P.; Liu, Lin; Herman-Mercer, Nicole M.; Mu, Cuicui; Roth, David A.; Schaefer, Tim; Striegl, Robert G.; Wickland, Kimberly P.; Zhang, Tingjun Atmospheric deposition to forests in the eastern USA
Atmospheric mercury (Hg) deposition to forests is important because half of the land cover in the eastern USA is forest. Mercury was measured in autumn litterfall and weekly precipitation samples at a total of 27 National Atmospheric Deposition Program (NADP) monitoring sites in deciduous and mixed deciduous-coniferous forests in 16 states in the...
Risch, Martin R.; DeWild, John F.; Gay, David A.; Zhang, Leiming; Boyer, Elizabeth W.; Krabbenhoft, David P.