Author
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Fries, George |
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Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/20/1995 Publication Date: N/A Citation: N/A Interpretive Summary: None. Technical Abstract: The polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are groups of compounds with similar chemical and toxicological properties. Carcinogenicity was the primary toxic end-point considered in setting previous regulatory policies, but recent concerns have focused on the possible endocrine-disrupting activities of the dioxins. Toxicity is related to the 2,3,7,8 pattern of chlorine substitution, a pattern that also leads to chemical and metabolic stability. Dioxins are insoluble in water, and concentrate in lipids of biological systems leading to low concentrations in fat of the general population. Environmental sources of dioxins are emissions from industrial chlorination processes and combustion of materials containing chlorine. Inhalation and water have been ruled out as important exposure pathways, which suggests that food is the primary source. Pathways of entry into food chains are aerial transport of emissions with deposition on plants, soils, and water. Major food sources appear to be fat-containing animal products and some seafoods. Generally, dioxins and other lipophilic compounds are not taken up and translocated by plants, so residues in foods and feeds derived from seeds should be negligible. Animals on high roughage diets, or those that ingest contaminated soil, are the most likely to accumulate dioxin residues from the environment. The conclusion that animal products are a major source of human exposure requires verification by appropriate food sampling programs and animal metabolism studies. If it is desirable to reduce human exposure to dioxins via the food supply, reduction of sources would be a more effective strategy than changing agricultural practices and food consumption patterns. |
