Study Shows Agent Orange Still a Health Threat in Vietnam

Agent Orange - the infamous toxic herbicide sprayed during the Vietnam War - still affects the American veterans and Vietnamese exposed to it more than 25 years ago, confirmed a study conducted by researchers at the Dallas campus of The University of Texas School of Public Health at Houston.

The study, published in the Journal of Occupational and Environmental Health, discovered that 19 of 20 blood samples from people living on a former U.S. military air base that conducted Agent Orange spraying missions were contaminated with high levels of dioxin.

To clear areas of dense jungle during the Vietnam War, the U.S. military sprayed Agent Orange herbicide between 1962 and 1971. The herbicide contained a potentially harmful dioxin that has been associated with cancer, immune deficiency, endocrine disruption, and birth defects.

More than 30 years ago, 7,000 gallons of Agent Orange were spilled into the soil, then moved to nearby river sediment near the Bien Hoa City U.S. military air base. The dioxin moved from sediment to fish in the contaminated rivers to people who ate the fish. In turn, breast milk from nursing mothers exposed their children to the toxin. Vietnam veterans were exposed to the dioxin via water contact.

"Our study shows how dioxin moves in the environment and the food chain," said Dr. Arnold Schecter, professor of environmental sciences at UT-Houston School of Public Health's Dallas campus and lead author of the study. "The large number of Vietnamese and American veterans contaminated with dioxins will help us better understand the health effects of this toxic compound."

"Hot spots," or places where dioxin contamination exists, continue to enter the bloodstream of the Vietnamese who live in southern Vietnam, said Dr. Schecter. "The dioxin we left behind 30 years later is still entering the Vietnamese through food, and getting into men, women and children," he said.

Dr. Schecter said dioxin levels in Vietnamese who were exposed to the toxin are as much as 135-fold higher than those found in Vietnamese who were not exposed. Prior studies have reported American Vietnam War veterans and Vietnamese ingested the toxin.

During the Vietnam War, some 18 million gallons of Agent Orange were sprayed in southern Vietnam, making it the largest-ever dioxin contamination. More than 36 million people now live in the area.

The next step, Dr. Schecter said, is to figure out the connection between dioxin contamination and disease. Even though it is not clear how many people have been contaminated with dioxin from Agent Orange, he says public health measures need to be taken.

"We have a great deal of evidence about the health effects of this form of dioxin," Dr. Schecter said. "There is a real need to reduce toxic substances in food and conduct more environmental studies to document other hot spots and health-effect studies in Vietnam."

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©2006 Texas Medical Center

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