Pesticide Exposure Effect on Breastfeeding in Second-Generation Yaqui Girls

by Terri Crawford Hansen
Environment and Science Reporter
Native American Times

SONORA VALLEY, Mexico—The problems began ominously with the Yaqui pueblo peoples who accepted pesticide practices during the 1950s.

Long-term research led by Professor Elizabeth Guillette, Ph.D., of the University of Florida found compelling proof that exposure to pesticides has produced negative health impacts over the years to the exposed Native American Yaqui communities.

Her latest research findings indicate some pre-adolescent daughters of mothers exposed to pesticide spraying will never be able to breast feed their babies—ever.

With others there is uncertainly. Although there is breast growth some daughters have not developed the mammary tissue needed to produce milk, or have developed a minimal amount.
As the pesticide-exposed girls matured breast size became much larger than normal, yet they had less mammary tissue and often none at all, while the unexposed girls were normal.

“Some of the most devastating injustices [are] visited on indigenous farming communities around the world,” an article in the Magazine of Pesticide Action Network said in response to the study. “High exposure to pesticides suffered by many indigenous peoples is a frequent indicator of these injustices.”

Guillette, whose research was published in the March 2006 issue of Environmental Health Perspectives said, “A large study, using my techniques, was done in India showing the exact same results.”

“The results underscore the importance of women protecting themselves from manufactured chemicals beginning at birth because they stay in the body,” Guillette told the University of Florida News Bureau.

The study proves pesticide exposures can cross generations and that daughters of mothers exposed to the spraying of agricultural chemicals can be affected.

The intensive industrial agricultural pesticide approach, called the “Green Revolution,” was born in the Yaqui homeland in the northwestern Mexican state of Sonora’s Yaqui Valley. The poverty-stricken Yaqui were split between accepting pesticides, herbicides and other agricultural toxicants. The valley Yaqui agreed to grow wheat treated with pesticides for export and for other purposes. The other Yaqui removed themselves to the foothills, avoiding pesticide use or exposure.

Guillette, who frequently consults with Theo Colborn, Ph.D., lead author of “Our Stolen Future,” a book that brought widespread attention to hormonal changes called endocrine disruption being wrought to wildlife and humans by common contaminants, said her own interest was piqued by the changes Colborn noted in wildlife. Another anthropologist referred her to the Sonoma Yaqui Valley, where research was promising with two groups virtually identical except for their exposures to pesticides.

Her first long-term study, published in the journal EHP in 1999, tested Yaqui children aged four and five. Study results indicated key differences between the two populations in fine motor skills such as hand-eye coordination, balance, short-term memory, simple problem solving and even the ability to draw a human figure.

Concluding her interview Dr. Guillette stated, “The future of our society depends on today’s children. Preventative action to protect them from contamination must occur now, including individual, national and global levels.”