The lab's discoveries have already demolished the conventional wisdom on the properties of uranium. Not only does the heavy metal appear to alter mammary cells at very low doses, but it also seems to interfere with normal hormonal signals. Sometimes the uranium follows the same pathways as estrogen, but sometimes it doesn't, which means it's triggering other endocrine responses as well. "We don't yet know the mechanism of how uranium is affecting these cells," Raymond-Whish says, "but we do know an estrogen receptor is involved. We see it in both animals and MCF-7 cells."

Although the work in Raymond-Whish's lab is considered pure research science, it is impossible to sift it from the real-world context of her family, her culture and her beliefs. Breast, uterine and ovarian cancers have risen steeply in Indian country since the advent of uranium mining. Having watched her grandmother and mother suffer, and now with two kids of her own, 14 and 4 years old, Raymond-Whish can't help but wonder if she's next in line.

But while Raymond-Whish's intimate acquaintance with cancer may harm her credibility as a dispassionate scientist, it may also propel her to help make startling discoveries where no one else has thought to look.

The lab's investigation started several years ago, when Northern Arizona University became part of a team that received a five-year grant from the National Cancer Institute. The project is designed to address community health care, so the local Navajo elders had a few suggestions. They told the scientists they wanted to know more about the health effects of uranium pollution.

"So I started adding uranium to the drinking water of my lab animals," recalls physiologist Cheryl Dyer, who was Raymond-Whish's faculty advisor at the time. "And because I'm an ovarian physiologist, I wanted to see what happened in the ovary." Uranium has long been known to be radioactive and toxic, but no one had ever looked at its effects on follicle counts, or the number of "pre" eggs - eggs in the ovary that have not yet been released for fertilization. Dyer and Raymond-Whish found that the number of pre-eggs declined with low exposure to uranium, and that the mice developed heavier-than-normal uteruses. Normally, a toxic chemical will cause an organ such as a kidney to shrink, not expand. "I said, 'Whoa, what is going on here?' " says Dyer. "I started to wonder if there were other heavy metals that cause these changes, and it turns out cadmium does the same thing. That's when a light bulb went off in my head. Cadmium is an estrogen mimic." All those decades of lab work with atomic elements, and "they had completely missed the boat on estrogen mimicry."

Raymond-Whish was the lead author of a paper showing the unexpected effects of uranium on mouse follicle counts, uterine weights and accelerated puberty. "Drinking Water with Uranium below U.S. EPA Water Standard Causes Estrogen Receptor Dependent Responses in Female Mice" was published in December in Environmental Health Perspectives, a peer-reviewed journal put out by the National Institutes of Environmental Health Sciences. Raymond-Whish concluded that uranium acts as an estrogen, and she recommended that Navajo girls and women be followed closely for reproductive cancers. In conversation, Dyer makes her opinion clear: The U.S. Environmental Protection Agency should lower its drinking water standard for uranium from 30 micrograms per liter to 20 micrograms, the Canadian standard. But Dyer and Raymond-Whish are tip-toeing out on a treacherous scientific limb by suggesting policy changes that are based on controversial data.

Raymond-Whish's work and its results have landed her in the middle of a scientific and regulatory quagmire. It's one thing to regulate a chemical known to be toxic at high doses; it's entirely another to suggest regulating minute levels of a substance that is readily found across a large swath of the American West. Many communities, not just those on the reservation, are affected by uranium. Recent tests in Colorado, for example, revealed that 37 cities and towns in the state depend on drinking water that exceeds federal levels for uranium and its daughter nuclides.


Uranium is not just an emotional issue for Raymond-Whish, but for the tribe as a whole. The legacy of mining the element on the 27,000-square-mile reservation is so deeply and collectively felt that the Navajo Nation banned it altogether in 2005 in the face of globally rising ore prices. During the '40s and the Cold War period, the U.S. government used yellow cake - or milled and concentrated uranium ore - to build nuclear weapons. The government stopped buying the ore for weapons in 1971, but the commercial nuclear energy market picked up the slack until the early 1980s. Only about a quarter of all U.S. uranium miners were Native American - Laguna, Hopi, Zuni and Ute as well as Navajo. But Native Americans have been disproportionately affected: Their tribal lands are still contaminated, and former miners suffer illnesses and deaths for which many families are still awaiting compensation.

Despite the tribal ban, at least five companies are seeking state permits in New Mexico to mine lands just off the reservation, including on tribal allotment land. In Arizona, 700 individual mining claims were filed in 2005. The prehistoric sea and river beds that run underground from Naturita, Colo., to Grants, N.M., and across to Moab, Utah, still hold an estimated 600 million pounds of low-grade ore. But for every 4 pounds of uranium extracted, 996 pounds of slightly radioactive waste is left over, in piles, in pits and eventually in the soil, arroyos and underground aquifers.