BIOACCUMULATION OF DIOXINS IN FOOD ANIMALS .2. CONTROLLED EXPOSURE STUDIES

Additional data have been obtained which relate the bioaccumulation of polychlorodibenzodioxins and polychlorodibenzofurans (PCDDs and PCDFs) in foraging chickens to the ingestion of soil contaminated at the low part per trillion (ppt) level. These new data indicate that both the concentration and congener profiles of PCDDs and PCDFs in eggs and body tissues, are correlated with the PCDD and PCDF concentration and congener profile seen in soil on which these chickens were grazing. Additionally, a cow grazing in these areas of low soil PCDD/PCDF contamination showed characteristic PCDD and PCDF profiles in milk. Breast milk from women living in the area did not show the characteristic PCDD/PCDF contamination. Controlled feeding studies of chickens have been initiated which are designed to demonstrate the transfer of PCDDs and PCDFs from soil to tissue and eggs and to establish the kinetics and equilibrium concentrations of the bioaccumulation. Levels and patterns of PCDDs and PCDFs in tissues and eggs from foraging animals appear to be closely related to the levels and patterns in the soils to which they are exposed. This suggests the possibility of animals functioning as sensitive biomonitors for low level soil contamination. In addition, if such animals are used for food, the possibility of human exposure to PCDDs and PCDFs must be considered. © 1990.