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CORVALLIS, Ore. - As American Indian tribes focus on traditional ways of living, scientists from tribal governments and Oregon State University have developed new guidelines for evaluating health risks stemming from contamination of native lands.

Studies funded by the U.S. Environmental Protection Agency have shown that tribal lands across the United States - from Arizona's Black Mesa region to Akwesasne, N.Y. to the Columbia River basin - are polluted by coal and uranium tailings, industrial and agricultural chemicals and nuclear waste. Now, tribes can assess their risks for contaminant exposure on the basis of traditional cultural practices from basket weaving and sweat lodges to consumption of local plants and animals.

Researchers at OSU have collaborated with tribal scientists to create a risk-assessment guidance manual featuring "exposure scenarios" for tribes in different eco-regions. EPA provided funding for the project.

What makes the manual unusual, experts say, is its targeted users. Unlike EPA standards, which are based mainly on urban and suburban lifestyles, the Traditional Tribal Subsistence Exposure Scenario and Risk Assessment Guidance Manual is aimed at tribal members who pursue, or wish to pursue, ancestral lifestyles close to the land, according to Anna Harding, a professor of public health at OSU and co-investigator in the study.

As an example, Harding pointed to EPA guidelines for fish consumption.

"EPA estimates that the average adult will consume about 17.5 grams of fish a day," she said. "But studies suggest that the average for Native Americans in areas where subsistence fishing is practiced may be more than a pound a day. So the EPA exposure scenario will underestimate risks for these people.

"And if the fish happen to come from a water source that is contaminated," Harding added, "the health risks may be much greater than currently accounted for."

Using historical and archaeological sources, as well as oral teachings, the research team recreated traditional natural resource use specific to the local environment. From there, they assessed not only diet, but also level of exposure to soil, water and air through skin, mouth and lungs. Clearly, more physical contact with contaminated environmental resources means more potential pathways for contaminants.

"There are many potential exposure pathways that are unique to Native Americans but are not accounted for in scenarios developed for the general public," said the study's principal investigator Barbara Harper, manager of the environmental health program for the Confederated Tribes of the Umatilla Indian Reservation.

"These pathways may be significant to people with traditional specialties, such as flint knapping, pottery-making, basket weaving, or using certain paints and dyes, smoke and smudges," added Harper, who is an associate professor affiliated with OSU's Department of Public Health.

Harding emphasized, however, that searching for pollutants was not a project objective, nor was evaluating the health of tribal members.

"Our goal was to describe the exposure scenarios for different ecosystems that would then enable the tribes to determine their own exposure risks," she said. "Contaminants are site-specific. Each tribe must make that assessment for itself."

Stuart Harris, director of the Department of Science and Engineering for the Confederated Tribes of the Umatilla, said "the need for understanding the pathways that directly involve the traditional American Indian cannot be understated."

"Our ties to the environment are much more complex and intense than is generally understood," said Harris, also a co-investigator on the study. "My tribal culture and religion are essentially synonymous with and inseparable from the land. I suspect this is true for many other tribal nations as well."

Modern tribal diets and lifestyles, while significantly different from the average suburban resident, are likely not as healthy as they once were, Harper pointed out.

"Our approach is to reconstruct original diets and lifestyles that reflect tribal health and natural resource restoration goals," she said. "The manual will enable tribes to evaluate risks based on their current resource-intensive lifestyles, as well as on their fully traditional lifestyles. There are certain exposures that are potentially underestimated for a broad cross-section of tribal members."

The researchers developed scenarios for four ecosystems in the West. For each scenario, they described key natural resources along with traditional diets and activities such as hunting and fishing, gathering foods and medicines, making material items, farming, gardening with irrigation, raising livestock, and pursuits associated with cultural heritage and identity, such as sweat lodge ceremonies.

On average, Harding says, Native Americans who engage in subsistence activities eat more game and fish, drink more water, and consume more native plant and animal foods than the average American.

"These differences become critical when the assessing risks of environmental contaminants," Harding said.

Exposure scenarios were developed for the following tribes located in various eco-regions of the U.S.:

• Confederated Tribes of the Umatilla Indian Reservation, located in eastern Oregon and Washington, categorized as "lower Columbia Basin plateau";

• Spokane Tribe, eastern Oregon and Washington, "lower Columbia Basin plateau";

• Elem (Pomo) Tribe, near Clear Lake, Calif., "Northwest forest/Mediterranean California";

• Washoe Tribe, northern California, "Sierra Nevada Mountains/Great Basin."

"It was a huge undertaking," Harding said. "It represents an important partnership between tribal and university scientists to develop new knowledge about how tribes may be exposed to environmental contaminants when practicing traditional activities as part of their cultural lifestyle."

Read more about the project in the spring 2008 issue of OSU's research magazine, Terra. To obtain a printed copy or CD of Traditional Tribal Subsistence Exposure Scenario and Risk Assessment Guidance Manual, contact Anna Harding, [email protected], 541-737-3830, or Barbara Harper, [email protected].