Science for Decision Making on Uranium Mining in Arizona

Analyze Ecological Risk of Contaminant Concentrations at Breccia Pipe Uranium Mines

Regional Studies

Ecological risks of uranium mining in the Grand Canyon region are unknown.1 Uranium mines are sources of radiation and chemical contaminants. Chemical analyses of plants and animals for uranium and other contaminants found in breccia pipes have not been performed. Exposure pathways were identified but not prioritized by risk.2 Local species have specialized behaviors that allow them to survive in the arid environment. These behaviors may also increase their exposure to contaminants. For example, some animals spend a lot of time in burrows, where they may inhale, ingest, or absorb uranium and other contaminants while digging, eating, preening, and hibernating. Existing protective thresholds developed using common laboratory animals may have limited use in assessing real-world risk given the behaviors of wild species.


Conduct an risk analysis for animals at breccia pipe uranium mines.


A terrestrial risk analysis was conducted.3 Highlights from this work include:

  • First terrestrial ecological risk analysis at uranium mines near Grand Canyon.
  • Risks from mining related chemicals were low for terrestrial animals.
  • Protective levels were not exceeded for herbivores or carnivores.
  • Uranium was not the driver of risk for animals.
  • Animals that eat invertebrates may have risk from arsenic, cadmium, copper, and zinc.



Specific Tasks

Task 15: Conduct ecological risk analysis integrating all data from previous studies in this plan


1 Alpine, Andrea E., ed., 2010, Hydrological, geological, and biological site characterization of breccia pipe uranium deposits in northern Arizona: U.S. Geological Survey Scientific Investigations Report 2010—5025, 353 p., 1 pl., scale 1:375,000

2 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

3 Hinck, J.E., Cleveland, D., Sample. B.S., 2021, Terrestrial ecological risk analysis via dietary exposure at uranium mine sites in the Grand Canyon watershed (Arizona, USA), Chemosphere, vol. 265,

Principal Investigators

Jo Ellen Hinck
Columbia Environmental Research Center

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Sites with Related Activities

Arizona 1 || Pinyon Plain (formerly Canyon) || Pinenut || Little Robinson