- Low-grade uranium ore is nicknamed "yellowcake" for
its color and powdered consistency. The Navajo have
another name: Leetso, or "yellow monster."
The yellow monster
surfaced on the Navajo Nation with uranium mining
that started in the 1940s and continued for the next
several decades. In its aftermath came illnesses
such as lung cancer among mine workers and worries
about environmental contamination among people who
live on that land.
The Navajos believe
you must gain knowledge of a monster to slay it and
restore nature's balance. Northern Arizona
University biochemist Diane Stearns and her Navajo
students are not only gaining knowledge, they are
adding to that knowledge with new discoveries about
uranium.
The fact that
uranium, as a radioactive metal, can damage DNA is
well documented. But what Stearns and her
collaborators recently have found is that uranium
can also damage DNA as a heavy metal, independent of
its radioactive properties.
Stearns and her team
are the first to show that when cells are exposed to
uranium, the uranium binds to DNA and the cells
acquire mutations. When uranium attaches to DNA, the
genetic code in the cells of living organisms, it
can change that code. As a result, the DNA can make
the wrong protein or wrong amounts of protein, which
affects how the cells grow. Some of these cells can
grow to become cancer.
"Essentially, if you
get a heavy metal stuck on DNA, you can get a
mutation," Stearns explained. Other heavy metals are
known to bind to DNA, but Stearns and her colleagues
are the first to identify this trait with uranium.
Their results were published recently in the
journals Mutagenesis and Molecular Carcinogenesis.
Their findings have
far-reaching implications for people living near
abandoned mine tailings in the Four Corners area of
the Southwest and for war-torn countries and the
military, which uses depleted uranium for anti-tank
weapons, tank armor and ammunition rounds. Depleted
uranium is what is left over when most of the highly
radioactive isotopes of uranium are removed.
"The health effects
of uranium really haven't been studied since the
Manhattan Project (the development of the atomic
bomb in the early 1940s). But now there is more
interest in the health effects of depleted uranium.
People are asking questions now," Stearns said.
The questions include
whether there is a connection between exposure to
depleted uranium and Gulf War Syndrome or to
increased cancers and birth defects in the Middle
East. Stearns said it is estimated that more than
300 tons of depleted uranium were used during the
first Gulf War. Military uses of depleted uranium in
weapons continue today.
Closer to home,
questions continue to be asked about environmental
exposure to uranium from mine tailings that dot the
landscape across the Navajo Nation.
"When the uranium
mining boom crashed in the '80s, it really crashed
and there wasn't much cleanup," Stearns said.
Estimates put the number of abandoned mines on the
Navajo Nation at more than 1,100.
NAU senior Hertha
Woody grew up on the Navajo Nation in Shiprock, N.M.
Before joining Stearns' research group, Woody said
she was not very aware of heavy metal contamination
of soil and water from a large uranium tailing pile
near her hometown. But now she wonders about the
ongoing health problems of her uncle who worked in
the uranium mine at Shiprock. And she worries about
others living in the area.
"My parents still
live there and drink the water," she noted.
There's another
Navajo word that Woody shares. It is hozho, which
relates to harmony, balance and beauty. Woody
explained that the yellow monster disrupts hozho and
that uranium should remain in the ground to ensure
balance. In fact, in the spring of 2005, Navajo
Nation President Joe Shirley, Jr., signed the Diné
Natural Resources Protection Act, which bans uranium
mining and processing on the Navajo Nation.
Woody said she has
learned a great deal and not just in the realm of
science. "It opens up doors and windows everywhere
else," she said, noting that the work has raised her
awareness about mine safety, tribal issues and
reclamation efforts.
"When we first heard
of the yellow monster, it was scary and not much was
understood until the research began and it was
passed on to the people through booklets and talks
at the chapter houses," said Sheryl Martinez, a
junior in NAU's nursing program and another member
of Stearns' research group. Martinez, also a native
of Shiprock, hopes to return to her community and
put her knowledge to work after graduation.
The funding for
Stearns' work is tied to improving health among
Native American communities. Stearns is the NAU
principal investigator of a grant jointly awarded to
NAU and the Arizona Cancer Center by the National
Cancer Institute. Louise Canfield is the principal
investigator on the grant for the Arizona Cancer
Center. Collectively, these two grants comprise the
Native American Cancer Research Partnership, a
consortium of cancer researchers and educators at
NAU and the Arizona Cancer Center. NACRP is one of
only five such partnerships in the nation and the
only one focused on Native American issues.
"The data on Native
Americans for cancer evidence is very poor," Stearns
said. "Navajo and Hopi may not get cancer to a
greater extent, but the survival rate is lower than
the general population." Stearns said the lower
survival rate might be more the result of limited
access to care or cultural boundaries that may
prevent people from seeking care.
A goal of the
partnership is to address these disparities by
training Native students for cancer-related careers.
In this way, Stearns
and her students can help slay the yellow monster,
whether on the Navajo Nation or abroad.