During the past decade a considerable amount of data has been generated concerning polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in humans from many geographical locations. To organize these data in a useful fashion for environmental purposes and for consideration of human toxicity, selected portions of our data are presented in a somewhat atypical fashion, by percentage contribution of individual congeners to total PCDD/Fs in human tissue, and to the total dioxin equivalents (TEq). This is done to better characterize congener contributions from environmental contamination in various geographical regions at this time and health-related levels. To present the findings in a global perspective, data from widely different locations are presented including the United States, Germany, Vietnam, the former Soviet Union, Thailand, Cambodia, China, South Africa, and Guam.

Polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) are of concern in Vietnam because of contamination from Agent Orange and other dioxin-containing chemicals. To map out levels of dioxins in Vietnam, between 1987 and 1991 pooled samples were collected in hospitals from discarded blood of adults and analyzed for dioxin content. Locations represented include Hanoi in the north, and thirteen areas in southern and central Vietnam. Because humans are at the top of the food chain, human blood dioxin levels can be used to monitor the environment and to acquire data of public health concern. Vietnamese adults, usually over the age of 40, were selected to increase the probability that 2,3,7,8-TCDD from Agent Orange, sprayed from 1962-1970 over 10% of the south, would be detected. One special group was included, veterans of the North Vietnam Army who served in the jungles of the south where Agent Orange was used. In general, considerable variation in TCDD level was observed, with elevated levels from certain areas in the south and also in the soldiers from the north of Vietnam who had served in the south. Seven hundred and twenty-one Vietnamese tissue samples were collected and are reported from twenty dioxin analyses.

Between 1984 and 1988, eight hospitalized surgical patients living in different provinces in the south of Vietnam were interviewed to estimate potential exposure to Agent Orange during the Second Indochina War and their adipose tissue polychlorinated dibenzodioxin and dibenzofuran (PCDD/F) levels were measured. Seven out of eight specimens had detectable 2,3,7,8-TCDD levels ranging from 3.2 to 56.7 ppt in a lipid basis with a mean of 25.2 ppt. Previous findings from northern Vietnamese patients not exposed to Agent Orange showed non detectable levels of TCDD. The relatively high level of 2,3,7,8-TCDD as compared to total PCDDs and PCDFs in fat tissue suggests its source is at least partially from Agent Orange. The medical diagnoses for the three patients with the highest levels of 2,3,7,8-TCDD in their adipose tissue were: primary carcinoma of the liver (56.7 ppt), adenoma of the prostate (55.9 ppt), and adenocarcinoma of the stomach (28.9 ppt). A causal relationship between dioxin levels and illness is neither implied nor proven in this paper consisting of case reports from a pilot study which is not epidemiologic in nature. Clinical history of potential exposure to a herbicide thought to be Agent Orange was in some instances correlated with elevated levels of 2,3,7,8-TCDD in adipose tissue specimens.