Dioxin-like contaminants (PCDD/Fs, PBDD/Fs, PXDD/Fs, PCBs, PCNs) & PBDEs in edible avian eggs other than chickens

The occurrence of dioxin-like environmental contaminants, polybrominated diphenylethers (PBDEs) and polychlorinated biphenyls (PCBs) was investigated in eggs of eleven avian species excluding chickens. The majority were duck and quail eggs, but smaller numbers of goose, turkey, guinea-fowl, pheasant, pea-fowl, gull, ostrich, emu and rhea eggs from retail outlets were also analysed using high-resolution sector-field mass spectrometry. Polychlorinated/brominated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs), PCBs and PBDEs were measured in 104 samples. Mixed halogenated dioxins, furans, biphenyls (PXDD/Fs & PXBs), and polychlorinated naphthalenes (PCNs) were investigated in ∼ 1/5^th of samples. These environmental contaminants were detected in all species at lipid weight maxima of 26 pg TEQ/g, 465 ng/g NDL-PCBs and 227 ng/g PBDEs. Except for PCDD/Fs and PBDD/Fs (detected in 90 % of samples), gull eggs showed highest contaminant levels. PBDD/F TEQ (max. 7.98 pg/g lipid) exceeded PCDD/F TEQ in 26% of duck eggs and elevated contaminant levels were recorded for other species. Different husbandry practices, access to soil and herbage under free-range conditions, seasonality and lower periodicity of egg laying may promote elevated contaminant levels. Dietary intakes of PCDD/F and PCB TEQ through consumption of duck eggs ranged from 0.04 to 0.44 pg TEQ/kg bw/week for adult consumers, and approximately doubled (0.08 - 0.94 pg TEQ/kg bw/week) when all measured DL-TEQ was included. Indicative intakes from eggs of other species were considerably higher, with corresponding values ranging from 0.44 - 5.3 and 0.51 to 6.2 pg TEQ/kg bw/week, respectively. Uniquely, the study provides baseline levels of emerging environmental contaminant occurrence and dietary exposure through eggs of hitherto unstudied avian species. The results emphasise the significance of non-regulated TEQ inputs. The doubling of TEQ intake through duck egg consumption when these emerging contaminants are included, suggests that the current limited focus on chlorinated congeners may provide an inadequate reflection of dietary exposure.