Dioxins and dioxin-like compounds in domestic meat

Abstract

Persistent environmental pollutants including polychlorinated dibenzo-p-dioxins, dibenzo- furans (PCDD/Fs), coplanar polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were analyzed in 65 meat samples collected from supermarkets across the U.S. in 2001. The samples included hamburger, sirloin steaks, pork chops, bacon, and whole chickens from nine different cities. The average dioxin toxic equivalency (TEQ) for all the samples was 0.55 pg/g lipid, with pork having the lowest levels. The TEQ levels were similar to recent values reported in the U.S. and appear to be declining. The sums of PBDEs averaged 1.71 ng/g lipid and represent the first extensive sampling of domestic meats. The PBDE levels in pork and chicken were 4 and 10 times higher, respectively, than levels reported in Europe for these foods. The presence of a few outliers raised the average PBDE sums and indicated that isolated sources of contamination may exist that, if identified, could be removed from the U.S. animal production chain. Introduction Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and biphenyls (PCBs) are ubiquitous, persistent, lipophilic pollutants. Polybrominated diphenyl ethers (PBDEs) are com- monly-used additive flame retardants that are also highly lipophilic and structurally similar to the PCDD/Fs and PCBs. While PCDD/F levels are decreasing in the environment and PCBs are no longer produced, PBDEs continue to be produced and their levels appear to be increasing in the environment and in humans over the past 10-20 years (Darnerud et al., 2001; deWit, 2002). The acute and chronic toxicity of dioxin-like compounds is well documented (Schecter, 1994), and, although PBDEs do not appear to have any acute toxicity, some studies have shown developmen- tal and neurological effects due to PBDE exposure (Darnerud et al., 2001). In order to better assess the risk from PBDEs, routes and magnitudes of exposure need to be investigated and characterized. Because human exposure to PCDD/Fs is almost entirely through the diet, it seems plausible that exposure to PBDEs may occur by this same route. In this study, we have analyzed typical domestic meats to update data on the current levels of PCDD/Fs and PCBs and to begin to define the levels of PBDEs found in these products. Materials and Methods Meat and poultry samples were purchased at large supermarkets in nine cities across the U.S. and shipped frozen to the USDA-ARS laboratory in Fargo, ND, for analysis. All samples were collected in 2001 and included bacon, hamburger, whole chickens, sirloin steaks, and pork chops from each location. The bacon and ground beef were analyzed whole; for the chickens, steaks, and chops, fat was trimmed and analyzed for 17 toxic PCDD/Fs and 3 copla- nar PCBs, or 7 marker PBDEs in separate analyses. Homogenized bacon or fat trimmings (5 g) were spiked with 15 13