Assessment of exposure to 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) in the Seveso area

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Since the ICMESA accident in 1976, the inhabitants of the affected area were required to comply with a number of hygiene regulations including the prohibition to farm and consume local agricultural products and keep poultry and other animals. In 1984 a Commission chaired by F. Pocchiari was asked to make an assessment of the exposure of the Seveso population to TCDD in the case the above-mentioned restrictions would be removed. The average level of TCDD in the soil was assumed to be 12 ppt. Several population groups with different exposure potentials were identified: (i) people not consuming locally-produced foods; (ii) people consuming in part locally-produced plant foods; and (iii) people consuming in part both locally-produced plant and animal foods. An ad hoc survey of local dietary habits and food production was carried out and the results were compared with national data. When estimating food consumptions, proper factors were used to take into account food amounts produced in the zone, but consumed by people living out of the area considered or discarded. Levels of TCDD in different food items were estimated by using available analytical data as well as soil-vegetation, soil-vegetation-animal, soil-animal translocation factors of TCDD as predictable from experimental data. An apparent half-life of 10 years was used in calculations to take into account the environmental degradation of TCDD. Intakes of TCDD were calculated for an average person living continuously in the contaminated area for 70 years and averaged over the entire lifetime. For people not consuming locally-produced foods the intake of TCDD was estimated to be 0.007 pg/kg b.w./day, in agreement with figures previously developed by other researchers. For people consuming locally-produced plant foods, the intake of TCDD was 0.7 pg/kg b.w./day. Lastly, intakes of TCDD ranging, as an average, between 2.0 and 6.7 pg/kg b.w./day were estimated for people consuming both locally-produced plant and animal foods.