How are Mercury Sources Determined? Active
Mercury Research Laboratory
Uses Specialized Equipment to Measure Mercury Isotopes in Water, Sediment, and Tissues
Mercury Isotope Measurements
Are Used to Determine Mercury Sources and Pathways
Mercury Isotopes are Measured in Fish Tissues
To Determine Sources and Exposure
USGS scientists use innovative isotopic identification methods to determine mercury sources in air, water, sediments, and wildlife.
Mercury is recognized as a neurotoxin that can accumulate in fish and move through the food chain to other wildlife and humans. Innovative techniques are used to measure differences in mercury isotopes and provide unique signatures that can differentiate mercury sources deposited from the atmosphere, released from local ongoing and legacy point sources, or mobilized from the watershed and transported downstream.
Scientists have used these techniques in the Great Lakes and the Northeastern United States to answer questions about mercury sources in fish. For example:
•Mercury signatures in Great Lake’s predatory fish were found to be more reflective of atmospherically sourced mercury than of sediment sourced mercury in each lake.
•Mercury signatures in fish in Northeast U.S. Streams indicated atmospheric sources in fish within forested-rural areas, whereas mercury isotope signatures indicated past (legacy) and present local sources in fish within predominantly urban-industrial areas.
•Mercury isotopic signatures provided a tool to understand how mercury cycling and accumulation in a predatory fish in Lake Michigan was affected by changes in sources and by food web alterations.
•Recently developed methods to separate methylmercury, the most bioaccumulative and toxic form of mercury in the environment, from other mercury forms and make isotope measurements will further improve methods to distinguish mercury sources in a wider array of settings.
These innovative methods inform efficient and economically sound mitigation actions that could reduce mercury exposure to fish, wildlife, and humans.
Below are other science projects associated with this project.
Food Web Changes Dampen Expected Reductions in Lake Trout Mercury Levels in Lake Michigan—Invasive Species Play Major Role
Mercury Isotope Ratios used to Determine Sources of Mercury to Fish in Northeast U.S. Streams
Below are publications associated with this project.
Isolation of methylmercury using distillation and anion-exchange chromatography for isotopic analyses in natural matrices
Use of stable isotope signatures to determine mercury sources in the Great Lakes
- Overview
USGS scientists use innovative isotopic identification methods to determine mercury sources in air, water, sediments, and wildlife.
Mercury is recognized as a neurotoxin that can accumulate in fish and move through the food chain to other wildlife and humans. Innovative techniques are used to measure differences in mercury isotopes and provide unique signatures that can differentiate mercury sources deposited from the atmosphere, released from local ongoing and legacy point sources, or mobilized from the watershed and transported downstream.
Scientists have used these techniques in the Great Lakes and the Northeastern United States to answer questions about mercury sources in fish. For example:
•Mercury signatures in Great Lake’s predatory fish were found to be more reflective of atmospherically sourced mercury than of sediment sourced mercury in each lake.
•Mercury signatures in fish in Northeast U.S. Streams indicated atmospheric sources in fish within forested-rural areas, whereas mercury isotope signatures indicated past (legacy) and present local sources in fish within predominantly urban-industrial areas.
•Mercury isotopic signatures provided a tool to understand how mercury cycling and accumulation in a predatory fish in Lake Michigan was affected by changes in sources and by food web alterations.
•Recently developed methods to separate methylmercury, the most bioaccumulative and toxic form of mercury in the environment, from other mercury forms and make isotope measurements will further improve methods to distinguish mercury sources in a wider array of settings.
These innovative methods inform efficient and economically sound mitigation actions that could reduce mercury exposure to fish, wildlife, and humans.
- Science
Below are other science projects associated with this project.
Food Web Changes Dampen Expected Reductions in Lake Trout Mercury Levels in Lake Michigan—Invasive Species Play Major Role
Combined analyses of mercury, nitrogen, and carbon isotopes in archived lake trout ( Salvelinus namaycush ) tissues and sediment cores in Lake Michigan from 1978 to 2012 indicated that lake trout mercury concentrations mirrored declines in mercury sources prior to the arrival of invasive species that changed mercury transfer through the food and dampened the expected decreases in mercury...Mercury Isotope Ratios used to Determine Sources of Mercury to Fish in Northeast U.S. Streams
Mercury isotope analyses were used to distinguish different sources of mercury to fish in 23 streams along a forested-rural to urban-industrial land-use gradient in the Northeastern United States. The use of mercury isotope measurements in fish tissue allow for distinguishing different sources of mercury that are bioaccumulating into the food web. Mercury isotope signatures in fish in forested... - Publications
Below are publications associated with this project.
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 importance. The lack of MeHg isotope measurements is due toAuthorsTylor Rosera, Sarah E. Janssen, Michael T. Tate, Ryan F. Lepak, Jacob M. Ogorek, John F. DeWild, Christopher L. Babiarz, David P. Krabbenhoft, James P. HurleyUse of stable isotope signatures to determine mercury sources in the Great Lakes
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 and Δ199Hg) identified three primary Hg sources for sediments: atmospheric, industrial, and watershed-derived. Results indicate atmospheAuthorsRyan F. Lepak, Runsheng Yin, David P. Krabbenhoft, Jacob M. Ogorek, John F. DeWild, Thomas M. Holsen, James P. Hurley