The US Department of Agriculture (USDA) conducts a statistically based survey of the domestic meat supply (beef, pork, chicken and turkey) to determine current levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and non-ortho-polychlorinated biphenyls (no-PCBs) every 5 years. Fat samples for each slaughter class were collected from US federally licensed slaughter facilities. The samples were processed and analysed for 17 PCDD/Fs and three no-PCBs. The sum of PCDD, PCDF and no-PCB toxic equivalencies (sum-TEQ) calculated using 2005 toxic-equivalency factors for all slaughter classes ranged from non-detect (n.d.) to 6.47 pg TEQ g-1 lipid. The median sum-TEQs, when n.d. = 0.5 LOD, for beef, pork, chicken and turkey were 0.66, 0.12, 0.13 and 0.34 pg TEQ g-1 lipid respectively. A comparison of the current survey with the previous three surveys shows a declining trend, with decreasing differences between medians; differences between the median sum-TEQs from 2007-08 and 2012-13 were -10%, -29%, -33% and -25% for beef, pork, chicken and turkey respectively. Several beef samples underwent further characterisation and congener patterns from these beef samples suggested pentachlorophenol treated wood as the likely exposure source. US consumer exposure to these compounds is relatively low and no slaughter class contributed more than 26% to the US Environmental Protection Agency (USEPA) chronic oral reference dose of 0.7 pg TEQ kg-1 bw day-1.
Keywords: Dioxins; PCBs; exposure; food survey; meat; poultry; temporal trends.