Toxic Substances Hydrology (Toxics) Program scientists use tracer tests to learn more about the transport and fate of contaminants in the environment. By placing a known concentration and amount of tracer in ground water or in a stream and monitoring the movement of the tracer, scientists can test hypotheses on the processes that control the transport and fate of many different types of contaminants. In many cases, changing natural systems and watching the response is one of the most efficient ways to learn how contaminants move in ground water or streams. The Toxics Program’s extensive use of tracer tests is unique when compared to other environmental research programs. Many Toxics Program investigations have used tracer tests as part of their investigation. The information presented on this page cuts across lines drawn by individual investigations and projects so that information on tracer tests conducted by the Toxics Program can be presented in one place.

Investigations and Research Activities

• Contamination from Sources with Mixed Wastes Investigations (including landfills and wastewater discharge)
• Sewage-Contaminated Ground Water, Cape Cod, Massachusetts
• Fate of Landfill Leachate, Norman Municipal Landfill, Norman, Oklahoma
• Contamination in Fractured-Rock Aquifers Investigations
• Multidisciplinary Characterization of Fluid Flow and Solute Transport in Fractured Rock, Mirror Lake, New Hampshire
• Transport Phenomena in Fractured Rock Research
• Hydrology of Fractured Rocks Research
• Investigations of Petroleum Related Contamination Investigations
• Crude Oil Contamination in the Shallow Subsurface, Bemidji, Minnesota
• Processes Affecting the Natural Attenuation of Gasoline in Ground Water, Galloway Township, New Jersey
• Watershed Contamination from Hard-Rock Mining Investigations
• Hard Rock Mining Contamination in Rocky Mountain Terrain -- Upper Arkansas River, Colorado
• Hard Rock Mining Contamination in Arid Southwest Alluvial Basins -- Pinal Creek, Arizona
• Coupled Transport and Geochemical Processes Determining the Fate of Chemicals in Surface Waters
• In-Stream Processes that Control the Fate of Emerging Contaminants
• USGS Surface-water quality and flow Modeling Interest Group (SMIG)
• USGS Standard Methods for Stream Tracer Injection Studies
• Bromide Stream Tracer Reference List
• Lithium Reader, Reading List on the Use of Lithium as a Stream Tracer
• Rhodamine WT Reader, Reading List on the Reactivity and Transport Characteristics of Rhodamine WT when Used as a Tracer
• Isotope Tracers of Biogeochemical and Hydrologic Processes
• Isotope Tracers Project, Research on the application of environmental isotopes in hydrology, geology, and biology
• Partitioning of Solutes between Solid and Aqueous Phases
• Transport and Transformation of Nutrients in Channels and Floodplains
• Testing New Field Methods and Modeling Techniques

Fact Sheets

• Use of tracer injections and synoptic sampling to measure metal loading from acid mine drainage: USGS Fact Sheet FS-245-96

Multilevel well-sampling array at the Cape Cod Research Site, MA, where many natural gradient tracer tests have been conducted. There are over 10,000 subsurface sampling ports.
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Headlines

• USGS Science Featured in a Special Issue of Applied Geochemistry on Contamination from Oil Production
• Monitoring Volatile Organic Compounds in Ground Water with Diffusion Samplers
• Hydrogen Measured in a New Test for Determining Subsurface Microbiological Activity at Contamination Sites
• Wastewater Indicators Shown to Degrade in Streams
• How Do Contaminants Mix at the Confluence of Streams
• What Mobilizes Arsenic in Ground Water
• New Information on the Long-Term Fate of Ammonium in Ground Water
• Tracing Wastewater - Using Unique Compounds to Identify Sources of Contamination
• Tracer Tests Steer Cleanup of Mined Watersheds

Processing samples during a stream tracer test on California Gulch, Animas River, CO
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Bibliography

• Publications on Tracer Tests (289 Publications)

New Publications

Upcoming Publications

• Application of iron and zinc isotopes to track the sources and mechanisms of metal loading in a mountain watershed: Borrok, D.M., Wanty, R.B., Ridley, W.I., Lamothe, P.J., Kimball, B.A., Verplank, P.L., and Runkel, R.L., Applied Geochemistry (IN PRESS).
• The use of fluoride as a natural tracer and the relationship to geologic features--Examples from the Animas River Watershed, San Juan Mountains, Colorado: Bove, D.J., Walton-Day, K., and Kimball, B.A., Geochemistry--Exploration, Environment, and Analysis (IN PRESS).

Newly Published

• Multi-scale measurements and modeling of denitrification in streams with varying flow and nitrate concentration in the Upper Mississippi River Basin, USA: Böhlke, J.K., Antweiler, R.C., Harvey, J.W., Laursen, A.E., Smith, L.K., Smith, R.L., and Voytek, M.A., 2009, Biogeochemistry, v. 93, p. 117-141, doi:10.1007/s10533-008-9282-8 (Advanced Web release).
• A simple technique for continuous measurement of time-variable gas transfer in surface waters: Tobias, C.R., Böhlke, J.K., Harvey, J.W., and Busenberg, E., 2009, Limnology and Oceanography--Methods, v. 7, no. 2, p. 185-195 (Journal table of contents with pdf links).

A tracer solution of ¹⁵N-enriched ammonium was injected upgradient of several multilevel sampling wells during a natural-gradient tracer test designed to assess the fate and transport of ammonium in a sewage plume on Cape Cod, Mass.
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Meetings and Conferences

• The USGS cosponsors the special session Hydrogeological Research Sites and Observatories at the 2008 AGU Fall Meeting, San Francisco, California, December 15-19, 2008