CORVALLIS - Researchers from Oregon State University have received a three-year, $449,970 grant from the Environmental Protection Agency to develop regional "exposure scenarios" for Native American tribes living in different eco-regions of the United States.
These exposure scenarios are designed to help tribes estimate risks from environmental pollutants from which their members may contact through their lifestyles.
EPA standards are based primarily on urban and suburban populations and are not suitable for typical tribal communities whose members pursue subsistence, or traditional lifestyles that may include more frequent "living off the land," said Anna Harding, an associate professor of public health at OSU and co-investigator in the study.
Especially, she added, when those lands may be contaminated.
"The EPA guidelines say, for example, that the average adult will consume about 17.5 grams of fish a day," Harding said. "But studies suggest that the average for Native Americans in areas where subsistence fishing is practiced may be over a pound a day, so the exposure scenario will underestimate risks for these people. And if the fish happen to come from a water source that is contaminated, the health risks may be much greater than currently accounted for."
Stuart Harris, director of the Department of Science and Engineering at the Confederated Tribes of the Umatilla Indian Reservation, 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, who also is co-investigator on the study. "My tribal culture and religion are essentially synonymous with and inseparable from the land."
Modern tribal diets and lifestyles, while significantly different from the average suburban resident, are likely not as healthy as they once were, said Barbara Harper, an OSU public health toxicologist and the study's principal investigator. "Our approach is to reconstruct original diets and lifestyles that reflect tribal health and natural resource restoration goals," Harper said.
Using literature review, as well as new research on activity levels associated with those lifestyles, will enable tribes to evaluate risks based on their current resource-intensive lifestyles, as well as on their fully traditional lifestyles, she added.
"There are certain exposures that are potentially underestimated for a broad cross-section of tribal members," Harper said. "For example, animal parts have many non-food uses that could contribute to personal exposure. Teeth and bones are used for decoration and whistles, skin is made into clothing, fish belly fat is rendered and used as a base for body paint, and so on.
"As with game, plants are used for more than just nutrition," she added. "Daily cleaning, preparation and ingestion of stored plants - and crafting of plant materials into household goods - occur throughout the year."
On average, Harding says, Native Americans engaged in subsistence activities eat more game and fish, drink more water, and consume more native plant and animal foods than the average American. EPA surveys show that the average American, for instance, will inadvertently consume about 50 milligrams of soil a day, through daily activities outside or eating vegetables like carrots that may include traces of dirt.
However, the subsistence intake rate for a tribal member is estimated to be 400 milligrams of soil a day, eight times higher than that of a suburban lifestyle.
"These differences become critical when assessing risks to environmental contaminants," Harding said. "Our goal with the study is to develop regional exposure scenarios for tribes living in five different ecosystems so that any tribes living within those areas can examine their own exposure factors and evaluate their risk for contamination."
Working with Harper, Harding, and Harris on the grant are Therese Waterhous, an OSU nutrition researcher; Tony Wilcox, an OSU exercise physiologist; and several graduate students.
Participating tribes located in various eco-regions include:
The researchers will develop scenarios for the different ecosystems describing key resources in the area, traditional diets, and traditional activities. Such activities may include 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.
Exposure factors evaluated will include exposure to air, water, soil, and natural resource use for food and materials specific to the local environment.
"There are many potential exposure pathways that are unique to Native Americans but not accounted for in scenarios developed for the general public," Harding said. "These pathways may be significant to people with traditional specialties, such as flint knapping, pottery and basket-making., or using certain paints and dyes, smoke and smudges.
"We're not specifically looking for contaminants," she emphasized. "Our goal is to describe the exposure scenarios for different ecosystems that will enable the tribes to determine their own exposure risks."
Harding said an advisory council that includes representatives from each of the participating tribes will evaluate and validate the researchers' findings.
"It is a huge undertaking," she said, "but this 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."
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Anna Harding, 541-737-3830