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Carleton Bern, PhD

Carl is a Research Soil Scientist with the USGS Colorado Water Science Center.

My research examines the geochemical interactions between water, rock, and soil in both natural and human-managed systems. I specialize in using isotopes and geochemical tracers to answer questions of both basic and applied research. Areas of focus in my recent work include:

  1. Using tritium to trace the ages of surface waters and water availability in the Upper Colorado River Basin as part of the USGS Next Generation Water Observing System (NGWOS)
  2. Salinity in surface waters and soils of the semiarid western U.S.
  3. Contaminants of concern like PFAS and selenium
  4. Water and soil effects from uranium mining
     

Professional Experience

  • 2016-present     Research Soil Scientist, USGS Colorado Water Science Center

  • 2010-2016          Research Soil Scientist, USGS Crustal Geophysics and Geochemistry Science Center

  • 2008-2010         Mendenhall Fellow, USGS Crustal Geophysics and Geochemistry Science Center

  • 2006-2008        Post-doctoral researcher, University of California, Santa Barbara
     

Education and Certifications

  • Ph.D.    University of Colorado, Boulder, Colorado, Ecology and Biogeochemistry

  • B.S.       Virginia Tech, Blacksburg, Virginia, Biology
     

Science and Products

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Image: View Down Kanab Creek

Technique Used to Distinguish Natural Background from Human-Caused Enrichment of Trace Elements in Soils

Human activities can enrich toxic trace elements like uranium and arsenic in the environment, but these elements also are from natural sources and occur at background levels. Scientists utilized a technique that identifies the background and the elemental fingerprint of human-caused enrichment and tested the new technique on data collected near uranium mines in Arizona.
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Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
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Technique Used to Distinguish Natural Background from Human-Caused Enrichment of Trace Elements in Soils

Human activities can enrich toxic trace elements like uranium and arsenic in the environment, but these elements also are from natural sources and occur at background levels. Scientists utilized a technique that identifies the background and the elemental fingerprint of human-caused enrichment and tested the new technique on data collected near uranium mines in Arizona.
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White crusts of natural salts along a tributary to Muddy Creek, Wyoming

Soil Disturbance Can Increase Stream Salinity in Semiarid Watersheds

Soil disturbance from construction of roads, pipelines, and well pads on naturally salt-rich soils was determined to be a potential factor resulting in increased salinity in a southern Wyoming stream. Construction can expose salt-rich soils in the subsurface to increased contact with rain and snow, thus mobilizing salts through runoff or water percolating into soils.
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
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Soil Disturbance Can Increase Stream Salinity in Semiarid Watersheds

Soil disturbance from construction of roads, pipelines, and well pads on naturally salt-rich soils was determined to be a potential factor resulting in increased salinity in a southern Wyoming stream. Construction can expose salt-rich soils in the subsurface to increased contact with rain and snow, thus mobilizing salts through runoff or water percolating into soils.
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Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Colorado and Utah National Atmospheric Deposition Program (NADP) sites

The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 4,300 weekly composite samples of precipitation from thirteen National Atmospheric Deposition Program (NADP) sites (CO02, CO08, CO09, CO10, CO21, CO89, CO91, CO92, CO93, CO96, CO97, CO98, and UT09) in Colorado and Utah were analyzed on archived samples obtained from NADP over various time periods between Janua
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Water Resources Mission Area

Geochemical and fallout radionuclide data for sediment source fingerprinting studies of the Loutsenhizer Arroyo and Sunflower Drain watersheds in western Colorado

This data release includes geochemical and fallout radionuclide data for suspended sediments and potential sediment source types for the Loutsenhizer Arroyo and Sunflower Drain watersheds in western Colorado. Suspended sediments were collected by passive samplers deployed in the stream channel of the watershed outlets during four study periods between August 2018 and August 2019. Potential sedimen
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Colorado Water Science Center

Geochemical data from batch experiments to test mobility of trace elements downgradient from breccia-pipe uranium deposits

This data release includes solid and aqueous chemical data related to a set of sequential laboratory batch experiments conducted to test and simulate the mobility of trace elements as natural waters contact ore from breccia pipe uranium (BPU) deposits located in northern Arizona. The experiments made use of aquifer-related, sedimentary rocks collected specifically for this study and archival ore m
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Colorado Water Science Center

GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements

In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS Earth Mappi
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Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Earth Mapping Resources Initiative (Earth MRI)

Surface Materials Data from Breccia-Pipe Uranium Mine and Reference Sites, Arizona, USA

This data release includes elemental analysis of soil samples collected at breccia-pipe uranium mines, at one undeveloped breccia-pipe uranium deposit, and at a reference site in northern Arizona. Samples were collected near the Arizona 1, Canyon, Kanab North, and Pinenut uranium mines, over the EZ2 breccia-pipe uranium deposit, and at the Little Robinson Tank reference site. Samples were collect
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Colorado Water Science Center

Laboratory data from testing parameters of EPA Method 3060A on Soils Contaminated with Chromium Ore Processing Residue 2013-2016

It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from solids containing chromium ore processing residue (COPR). We systematically tested modifications to prescribed parameters of EPA 3060A towards improving extraction efficiency of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil from New Jersey (NJ). The alkaline extraction fluid leached Al, Si, and B from th
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Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
heavy mineral sands
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Heavy mineral sands, Folly Beach, South Carolina
White crusts of natural salts along a tributary to Muddy Creek, Wyoming
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White crusts of natural salts along a tributary to Muddy Creek, WY
Filter Total Items: 23

Assessment of salinity retention or mobilization by sediment-retention ponds near Delta, Colorado, 2019

Salinity control efforts in the Colorado River Basin have focused on mobilization of salts from irrigated land, but nonirrigated rangelands are also a source of salinity. In particular, lands where soils have formed from the Late Cretaceous Mancos Shale under arid and semiarid climates contain considerable quantities of salt, mainly in the subsurface. Hundreds of thousands of contour furrows and c
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Rodney J. Richards, Carleton R. Bern, Victoria Moreno
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Water Resources Mission Area, Colorado Water Science Center

Source contributions to suspended sediment and particulate selenium export from the Loutsenhizer Arroyo and Sunflower Drain watersheds in Colorado

Selenium in aquatic ecosystems of the lower Gunnison River Basin in Colorado is affecting the recovery of populations of endangered, native fish species. Dietary exposure is the primary pathway for bioaccumulation of selenium in fish, and particulate selenium can be consumed directly by fish or by the invertebrates on which fish feed. Although selenium can be incorporated into particulate matter v
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Carleton R. Bern, Cory A. Williams, Christopher G. Smith
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Water Resources Mission Area, St. Petersburg Coastal and Marine Science Center, Colorado Water Science Center

Examination of dissolved uranium concentrations in regional shallow groundwater relative to Operable Unit 8 of the Denver Radium Superfund Site

A radium industry existed between about 1914 and 1920 in Denver, Colorado, with operations located along the South Platte River. Sites associated with that industry were contaminated with radium and uranium processing residues and were incorporated into clean-up efforts as Operating Units (OUs) of the Denver Radium Superfund Site. Concentrations of uranium exceeding the U.S. Environmental Protecti
Authors
Carleton R. Bern
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Water Resources Mission Area, Colorado Water Science Center

Characterization of and temporal changes in groundwater quality of the Upper Black Squirrel Creek Basin, El Paso County, Colorado, 2018–20

In 2018–20, the U.S. Geological Survey, in cooperation with Upper Black Squirrel Creek Ground Water Management District, sampled 48 wells for Phase III of a multiphase plan investigating groundwater quality in the alluvial aquifer of the Upper Black Squirrel Creek Basin (UBSB), El Paso County, Colorado. Results for samples collected from October to December each year were used to assess spatial an
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Zachary D. Kisfalusi, Nancy J. Bauch, Carleton R. Bern
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Water Resources Mission Area, Colorado Water Science Center

Laboratory simulation of groundwater along uranium-mining-affected flow paths near the Grand Canyon, Arizona, USA

Mining of volumetrically small, but relatively enriched (average 0.6% U3O8) breccia pipe uranium (BPU) deposits near the Grand Canyon, Arizona, USA has the potential to affect groundwater and springs in the area. Such deposits also contain base metal sulfides that can oxidize to generate acid mine drainage and release trace metals. In this study, sequential batch experiments were conducted to simu
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Carleton R. Bern, Kate M. Campbell, Katherine Walton-Day, Bradley S. Van Gosen
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Water Resources Mission Area, Colorado Water Science Center

Water–rock interaction and the concentrations of major, trace, and rare earth elements in hydrocarbon-associated produced waters of the United States

Studies of co-produced waters from hydrocarbon extraction across multiple energy-producing basins have generally focused on major ions or a few select tracers, and studies that examine trace elements and involve laboratory experiments have generally been basin specific. Here, new perspective is sought through a broad analysis of concentration data for 26 elements from three hydrocarbon well types
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Carleton R. Bern, Justin E. Birdwell, Aaron M. Jubb
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Water Resources Mission Area, Energy Resources Program, Geology, Energy & Minerals Science Center, Colorado Water Science Center

Nontuberculous mycobacterial disease and molybdenum in Colorado watersheds

Nontuberculous mycobacteria (NTM) are environmental bacteria that may cause chronic lung disease. Environmental factors that favor NTM growth likely increase the risk of NTM exposure within specific environments. We aimed to identify water-quality constituents (Al, As, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Mo, Ni, K, Se, Na, Zn, and pH) associated with NTM disease across Colorado watersheds. We conducted a
Authors
Ettie M Lipner, Joshua French, Carleton R. Bern, Katherine Walton-Day, David Knox, Michael Strong, D. Rebecca Prevots, James L Crooks
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Water Resources Mission Area, Colorado Water Science Center

Salt flushing, salt storage, and controls on selenium: A 31-year mass-balance analysis of an irrigated, semiarid valley

Salinity, selenium, and uranium pose water‐quality challenges for the Arkansas River in southeastern Colorado and other rivers that support irrigation in semiarid regions. This study used 31 years of continuous discharge and specific conductance (SC) monitoring data to assess interannual patterns in water quality using mass balance on a 120‐km reach of river. Discrete sampling data were used to li
Authors
Carleton R. Bern, Michael J. Holmberg, Zachary D. Kisfalusi
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Water Resources Mission Area, Colorado Water Science Center

Effects of John Martin Reservoir on water quality and quantity: Assessment by chemical, isotopic, and mass-balance methods

Water quality and quantity can be influenced by transit through and storage in reservoirs. Assessing such effects can be challenging, however, because of mixing and residence times, and inter-annual net storage and release from both the reservoir itself and surrounding porosity. Here, different methodologies were used to assess the effect of John Martin Reservoir (JMR), located on the Arkansas Riv
Authors
Carleton R. Bern, Michael J. Holmberg, Zachary D. Kisfalusi
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Water Resources Mission Area, Colorado Water Science Center

Comment on “Particle fluxes in groundwater change subsurface rock chemistry over geologic time”

Over the last decade, studies at the Shale Hills Critical Zone Observatory (Shale Hills) have greatly expanded knowledge of weathering in previously understudied, shale-mantled terrains, as well as Earth's Critical Zone as a whole. Among the many discoveries made was the importance of redistribution and losses of micron-sized particles during development of shale-derived soils. A geochemical finge
Authors
Carleton R. Bern, Tiffany Yesavage
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Water Resources Mission Area, Colorado Water Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

Improved enrichment factor calculations through principal component analysis: Examples from soils near breccia pipe uranium mines, Arizona, USA

The enrichment factor (EF) is a widely used metric for determining how much the presence of an element in a sampling media has increased relative to average natural abundance because of human activity. Calculation of an EF requires the selection of both a background composition and a reference element, choices that can strongly influence the result of the calculation. Here, it is shown how careful
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Carleton R. Bern, Katherine Walton-Day, David L. Naftz
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Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Colorado Water Science Center

Dual-phase mass balance modeling of small mineral particle losses from sedimentary rock-derived soils

Losses of small mineral particles can be a significant physical process that affects the elemental composition of soils derived from sedimentary rocks. Shales, in particular, contain abundant clay-sized minerals that can be mobilized by simple disaggregation, and solutional weathering is limited because the parent rock is composed primarily of recalcitrant minerals previously subjected to continen
Authors
Carleton R. Bern, Tiffany Yesavage
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Water Resources Mission Area, Colorado Water Science Center

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