Science for Decision Making on Uranium Mining in Arizona

Exposure Characterization in Plants and Animals through the Mine Life Cycle

At EZ Complex

EZ Complex Life Cycle

The EZ complex represents premining, udevelopment conditions at a mineralized site.

Vegetation, terrestrial invertebrates, and small rodents were collected for chemical and radiological exposure characterization at

  • Arizona 1 Mine and reference areas in the summer of 2015 (before reclamation ).1
  • Pinenut Mine and reference areas in the summer of 2015 (during active mining).1
  • Pinyon Plain (formerly Canyon) Mine in the summer of 2013 (before mining).2
  • EZ breccia pipes in the summer of 2015 (vegetation only; known uranium-mineralized but undeveloped breccia pipes).
  • Kanab North Mine in 2015 (decades after mining, before reclamation).3


  • We used traditional and new survey tools to understand how mining activities can affect local food webs. Chemicals can enter animals by ingestion, inhalation, absorption, and dietary transfer.1,2,3,4,5,6,7,8
  • Plants and animals take up mining-related radionuclides, uranium, other elements but direct effects were not linked.1,2,3
  • Radiation levels in plants and animals were low. Radiation enters rodents through soil interactions (burrowing, incidental ingestion, bathing, etc.) or their diet. Radium-226 was below protective levels. It is of most concern for rodent health.2,3,8
  • Tadpoles in the mine pond accumulated mining-related chemicals. Arsenic and selenium levels exceed protective thresholds.2



Specific Tasks

Task 5a: Compile/evaluate existing and newly collected monitoring data from various agencies/sources
Task 5c: Collect/analyze samples from biota with focus on trust resources
Task 7a: Conduct species surveys
Task 17: Determine biological effects of uranium + trace element mixtures


1 Cleveland, D., Hinck, J.E., Lankton, J.S., 2021, Elemental and radionuclide exposures and uptakes by small rodents, invertebrates, and vegetation at active and post-production uranium mines in the Grand Canyon watershed: Chemosphere, vol. 263,

2 Hinck, J.E., Cleveland, D., Brumbaugh, W.G., Linder, G., and Lankton, J., 2017, Pre-mining trace element and radiation exposure to biota from a breccia pipe uranium mine in the Grand Canyon (Arizona, USA) watershed: Environmental Monitoring and Assessment, February 2017

3 Cleveland, D.M., Hinck, J.E. and Lankton, J.S., 2019, Assessment of chronic low-dose elemental and radiological exposure of biota at the Kanab North uranium mine site in the Grand Canyon watershed: Integrated Environmental Assessment and Management 15:112-125,

4 Hinck, J.E., Linder, G., Darrah, A.J., Drost, C.A., Duniway, M.C., Johnson, M.J., Mendez-Harclerode, F.M., Nowak, E.M., Valdez, E.W., Wolff, S., and van Riper III, C., 2014, Exposure pathways and biological receptors--Baseline data for the Canyon Uranium Mine, Coconino County, Arizona: Journal of Fish and Wildlife Management, v. 5, no. 2, p. 422-440

5 Klymus, K.E., Richter, C.A., Thompson, N., and Hinck, J.E., 2017, Metabarcoding of Environmental DNA Samples to Explore the Use of Uranium Mine Containment Ponds as a Water Source for Wildlife: Diversity 2017, v. 9, no. 4.

6 Valdez, E.W., Hanttula, M.K., and Hinck, J.E. 2021. Seasonal activity and diets of bats at uranium mines and adjacent areas near the Grand Canyon. Western North American Naturalist: Vol. 81 :1-18,

7 Mann, R.K., Duniway, M.C., 2020, Vegetation cover and composition data in environments surrounding uranium mines in the Grand Canyon ecosystem, U.S. Geological Survey data release,

8 Minter, K.M., Jannik, G.T., Hinck, J.E., Cleveland, D., Kubilius, W.P.,and Kuhne, W.W., 2019, Biota dose assessment of small rodents sampled near breccia pipe uranium mines in the Grand Canyon watershed: Health Physics 117:20-27