Research by Region: United States - West

California / Nevada

Environmental Radiotracers: (ERT)
The Environmental Radiotracers (ERT) Project employs natural and artificial radionuclides to identify and model important particle transport processes in diverse systems. Since its inception in the early 1980s, John Robbin's technique-based project has given particular attention to radiometric dating of sediments. In addition to the role that sediments play in the regulation of nutrients and contaminants in aquatic systems, they frequently possess retrievable records of present and historical changes in ecosystem status and constituent loads due to natural or human causes.
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Environmental Radiotracers: Vertical Sediment Transport Models for Lake Tahoe
This ERT project involved developing self-consistent multi-tracer models of Lake Tahoe sediment accumulation, mixing and geochemistry as a means of chronicling the impact of watershed alteration and recent accelerated nutrient additions to this fragile ecosystem. In collaboration with David Edgington, the Great Lakes Water Institute, and individuals from the Tahoe Limnological Laboratory, the team examined 210Pb records from a core collected in 1981 and subsequently developed several mathematical models to interpret radionuclide data in the 1981 core plus two cores collected in 1991.
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Colorado

Environmental Radiotracers: Terrace Lake, CO
The ERT Project consists of a series of sub-projects, including one (now complete) in Terrace Lake, CO. In 1994, the U.S. Geological Survey conducted an extensive bed sediment geochemical survey in Terrace Reservoir, near Summitville, southwestern, Colorado. Attempts to develop a sediment-geochemical history of the reservoir using 137Cs and 210Pb indicate that the onset of trace element enrichment substantially predates the onset of heap-leach mining operations at Summitville.
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Idaho

Environmental Radiotracers: Couer D'Alene Lake The ERT Project consists of a series of sub-projects, including one (now complete) in Idaho.

Horowitz, A.J., K.A. Elrick, J.A. ROBBINS, and R.B. Cook. A summary of the effects of mining and related activities on the sediment-trace element geochemistry of Lake Coeur d'Alene, Idaho, USA. Journal of Geochemical Exploration 52:135-144 (1995).