Author
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Fries, George |
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Submitted to: Reviews of Environmental Contamination and Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/6/1994 Publication Date: N/A Citation: N/A Interpretive Summary: None. Technical Abstract: Many organic contaminants are present in agricultural environments leading to exposure of animals and potential residues in animal products. Contamination can be widespread from aerial transport of semivolatile compounds, or localized as a result of accidental emissions and spills, improper waste disposal, and areas where banned products were used in the past. This evaluation of chemicals and transport processes indicates that halogenated hydrocarbons, including dibenzo-p- dioxins, dibenzofurans, biphenyls, and insecticides persisting from past use, are the contaminants of greatest concern. These compounds resist degradation and tend to accumulate in the fat of animals and their products. Plants and soils are the usual points of entry of contaminants into agricultural systems. The lipophilic halogenated hydrocarbons are not taken up and translocated by plants, and contamination is a surface phenomenon resulting from aerial deposition, or redeposition of compounds volatilized from soil. Thus, roughages used as cattle feed are the most important pathway of animal exposure and transport to human foods. Another pathway of exposure is ingestion of contaminated soil, and cattle also are the most vulnerable to exposure by this pathway. Poultry and swine are less vulnerable to exposure because they are fed protected seeds and are usually confined. Other contaminants like the polycyclic aromatic hydrocarbons, phthalate esters, acid phenolics, and nitrosamines also may occur widely. These compounds are not transported to animal products because they are water soluble, or are metabolized to products that do not bioaccumulate. |
