Dioxin, dibenzofuran, and coplanar PCB levels in Laotian blood and milk from agent orange-sprayed and nonsprayed areas, 2001.

Agent Orange, a phenoxyherbicide contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), was used by American military forces during the United States-Vietnam war between 1962 and 1971 primarily as a defoliant to destroy forests where enemy troops might find cover. Agent Orange was used mainly in Vietnam, but also to a lesser extent in Laos and Cambodia. In Laos, there have been no prior studies of TCDD contamination from Agent Orange, despite known defoliation and documented records of Agent Orange spraying. This article presents findings of TCDD in human blood and milk from two geographic areas in Laos: Vientiane, a nonsprayed area, and Sepone, an Agent Orange-sprayed area. German and Canadian laboratories used high-resolution gas chromatography-mass spectrometry to measure 7 dioxin, 10 dibenzofuran, and 4 non-ortho or coplanar polychlorinated biphenyls in Laotian blood and milk samples. Most subjects tested in this Laos Ministry of Health Study showed low dioxin and dibenzofuran levels, consistent with what would be expected in a primarily rural nonindustrial country. These findings are consistent with relatively low dioxin and dibenzofuran levels recently found in food from these same areas. The chemically and toxicologically related non-ortho PCBs were measured but were found at low levels compared to specimens from other countries, presumably because of less industrialization and industrial pollution in Laos.