Navajo Researcher's Work Hits Close to Home

La Monica Everett-Haynes
Feb. 25, 2015

It is a legacy that may be written in the DNA of some of Monica Yellowhair's fellow tribal members: The prevalence of uranium mining in the southwestern U.S. during the Cold War often led to tribal members, their lands and structures being exposed to radiation.

Monica Yellowhair (Photo: Ken Sterns/UANews)

Uranium is a naturally occurring radioactive heavy metal that proved to be important during the era of expanded atomic bomb testing and also in weapons. During the mining and refinement of uranium, wastes may be introduced into the environment via wind and water — which was the case on tribal lands.

Think of fruit. "It's like having all the seed when what you want is just the juice," said Yellowhair, a University of Arizona postdoctoral student studying pharmacology and toxicology.

At the UA, Yellowhair is investigating how exposure to depleted uranium creates cancer-causing damages and other alterations in a person's DNA, and how DNA can repair itself — an area of research that lacks a critical mass. She intends for this research to inform future therapies that would be employed to reverse damage.

She is a member of the UA Cancer Center team to recently receive part of a $13 million grant from the Partnership for Native American Cancer Prevention for biomedical field research involving the Navajo Nation, the Hopi reservation and the Tohono O’odham Nation.

Growing up in Kayenta, Arizona, within the Navajo Nation — about a 30-minute drive south of many of those mines — Yellowhair often would hear stories of tribal members working in the now-abandoned uranium mines, unaware of the health risks. Even after mine closures, some of the equipment used for mining would be turned over to tribal members who then built hogans, storage units and other structures.

"This was during the Cold War era and the race to make the atomic bomb, and much of the mining was done without fencing off the mines, notifying people or remediation," said Yellowhair, also a UA Cancer Center researcher.

The U.S. Environmental Protection Agency reports that, since 2008, it has worked with the Navajo Nation to evacuate and demolish dozens of structures and other property, rebuilding homes for displaced families. With the Navajo Nation, the agency found that more than 760 additional structures required either an investigation or remediation. 

The agency also reports contaminated water sources on the Navajo Nation. Beginning in 2006, government agencies began sampling hundreds of unregulated water sources, which have been (and continue to be) important sources for many tribal members and livestock, Yellowhair said. Findings indicated that dozens of sources exceeded standards for radionuclides, including uranium. Eventually, signs were posted to discourage people from relying on the contaminated water sources, and several water wells were shut down.

While such efforts continue, Yellowhair said they are not enough to erase decades-old problems associated with possible and actual uranium contamination.

"It seems like a basic question: Can the DNA repair itself, or does it replicate in ways that cause deformities? If so, what cancers does it cause? We do know that uranium exposure can cause cancers, but likely not just leukemia," said Yellowhair, who pursued the advanced degree after graduating from Northern Arizona University. In fact, she was exposed to this area of research while working with Diane Stearns, a professor in NAU's chemistry and biochemistry department, opting to pursue advanced studies at the UA specifically so she could greatly expand her research.

Another significant research question Yellowhair is pursuing is whether the chemical properties of uranium, in addition to its radioactivity, cause DNA damage. Beyond her current work, she plans to also investigate the long-term environmental effects of uranium exposure on the land, with a specific focus on translational research.

"This issue is close to home — it's where I grew up," she said. "I can give back to my community even when I am not physically there."

For related UANews.org coverage on STEM, read:

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