The Science of Dioxin

August 31, 2015

Scientific Paper Finds that Exposure to Agent Orange in Vietnam Did Not Result in Persistent Transgenerational Exposure through Human Milk

A review article published in the scientific journal Birth Defects Research, entitled “Agent Orange Exposure and 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) in Human Milk,” has concluded that exposure to Agent Orange in Vietnam did not result in “persistent transgenerational exposure through human milk.”

The authors of the paper are Anthony R. Scialli (of Scialli Consulting LLC, Georgetown University School of Medicine, and George Washington University School of Medicine and Health Sciences in Washington, D.C.), and Deborah K. Watkins and Michael E. Ginevan (of M.E. Ginevan & Associates in Silver Spring, Maryland).

The authors explained in the introduction to their paper that the U.S. war in Vietnam involved the spraying of herbicides in the south to remove foliage cover for northern Viet Nam and Viet Cong troops and to decrease access of these combatants to food crops. As the authors noted, Agent Orange was the herbicide used in the greatest volume, consisting of equal parts of the n-butyl esters of 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid, the latter of which included 2,3,7,8-tetrachlorodibenzo-p-dioxin (“TCDD”).

The authors acknowledged that there has been concern that TCDD continues to be present in the milk of Vietnamese women as well as concern that milk is a source of transgenerational exposure to TCDD. In their paper, the authors incorporated a broad survey of TCDD levels in human milk worldwide and took a further detailed look at TCDD measurements in human milk in Vietnam.

Following their review, the authors concluded that:

  • Measurements of TCDD in human milk in Vietnam today do not support the idea that Agent Orange is a substantial source;
  • Breastfeeding is “not a mechanism by which TCDD from Agent Orange can be transmitted from one generation to the next”;
  • Current TCDD concentrations in human milk in Vietnam are “not pervasively elevated by Agent Orange used during the war”; and
  • Human milk is “not a significant pathway for Agent Orange-related second generation TCDD exposure.”

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Article Cites Potential of Dioxin in Smoke from California Wildfires

The dry summer in California has led to a significant number of wildfires, which has led to air pollution concerns – and to an article suggesting that wildfire smoke might contain dioxin.

The article, “Summer Fires: The Effects on Air Pollution and Health,” observed that dioxins “can be formed during combustion if the compounds burnt contain chlorine atoms.” It stated that the presence of dioxins in wildfire smoke is “not very likely” but that:

if fires spread and reach inhabited areas, and if houses/buildings are burnt, there is the risk of dioxin emissions. The chances are especially high if plastic materials catch fire.

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