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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Food Animal Metabolism Research » Research » Publications at this Location » Publication #244243
Title: Evaluation of Background Exposures of Americans to Dioxin-Like Compounds in the 1990's and the 2000's

Author
item LORBER, MATTHEW - Environmental Protection Agency (EPA)
item PATTERSON, DONALD - Consultant
item Huwe, Janice
item KAHN, HENRY - Environmental Protection Agency (EPA)

Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2009
Publication Date: 9/4/2009
Citation: Lorber, M., Patterson, D.G., Huwe, J.K., Kahn, H. 2009. Evaluation of Background Exposures of Americans to Dioxin-Like Compounds in the 1990's and the 2000's. Chemosphere. 77:640-651. DOI:10.1016/j.chemosphere.2009.08.016.

Interpretive Summary: Dioxins are a class of environmental contaminants found throughout the world that enter the food supply mainly through food producing animals. Because of potential health risks associated with dioxin exposure, in April 1991 the US Environmental Protection Agency (EPA) undertook an assessment of the human health risks associated with dioxin exposure. To calculate human intake of dioxins for the assessment, the US EPA used data available at the time for dioxin residue levels in the major food sources: meat, poultry, fish, eggs, and dairy and estimates of typical US consumption of these food groups. In addition, the US EPA looked at average dioxin body burdens in the US population estimated by the Center for Disease Control and Prevention (CDC) in the National Health and Nutritional Examination Survey (NHANES). Since 1991 new data has become available on dioxin levels in foods, and the CDC has issued more recent measurements of average dioxin body burdens (NHANES 2001/2). Using these latest findings, the US EPA compared intake and body burden estimates from the 1990s data and the 2000 data and concluded that exposure to dioxins has gone down, but not significantly, and average US body burdens have not changed over the last decade.

Technical Abstract: The US Environmental Protection Agency’s 2004 Dioxin Reassessment included a characterization of background exposures to dioxin-like compounds, including an estimate of an average background intake dose and an average background body burden. These quantities were derived from data generated in the mid-1990s. Studies conducted in the 2000s were gathered in an attempt to update the estimates generated by the Reassessment. While these studies suggest declines in the average background dose and body burden, a precise quantification of this decline, much less a conclusion that a decline has indeed occurred, cannot be made because of the inconsistency of study design and data sources, and the treatment of non-detects in the generation of congener average concentrations. The average background intake of the Reassessment was 61.0 pg TEQ/day, and using more current data, the average background intake was 40.6 pg TEQ/day. The average body burden from the surveys in the mid-1990s was 22.9 pg TEQ/g lipid weight (ppt lwt). More recent blood concentration data, from NHANES 2001/2, suggest an adult average at 21.7 ppt TEQ lwt. These values were generated substituting ND = ½ DL or ND = DL/sq rt (2); results are provided for ND = 0 and analyses conducted to evaluate the impacts of this substitution. A more detailed examination of beef and pork data from similarly designed national statistical surveys show that declines in pork are statistically significant while the beef concentrations appeared to have remained constant between the time periods.