The transfer of environmental contaminants (Brominated and Chlorinated dioxins and biphenyls, PBDEs, HBCDDs, PCNs and PFAS) from recycled materials used for bedding to the eggs and tissues of chickens.

Some types of poultry bedding made from recycled materials have been reported to contain environmental contaminants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, dioxins), polychlorinated biphenyls (PCBs) brominated flame retardants (BFRs) polychlorinated naphthalenes (PCNs), polybrominated dioxins (PBDD/Fs), perfluoroalkyl substances (PFAS), etc. In one of the first studies of its kind, the uptake of these contaminants by chicken muscle tissue, liver, and eggs from three types of recycled, commercially available bedding material was simultaneously investigated using conventional husbandry to raise day old chickens to maturity. A weight of evidence analysis showed that PCBs, polybrominated diphenylethers (PBDEs), PCDD/Fs, PCNs and PFAS displayed the highest potential for uptake which varied depending on the type of bedding material used. During the first three to four months of laying, an increasing trend was observed in the concentrations of ΣTEQ (summed toxic equivalence of PCDD/Fs, PCBs, PBDD/Fs, PCNs and polybrominated biphenyls), NDL-PCBs and PBDEs in the eggs of chickens raised on shredded cardboard. Further analysis using bio-transfer factors (BTFs) when egg production reached a steady state, revealed that some PCB congeners (PCBs 28, 81, 138, 153 and 180) irrespective of molecular configuration or chlorine number, showed the highest tendency for uptake. Conversely, BTFs for PBDEs showed good correlation with bromine number, increasing to a maximum value for BDE-209. This relationship was reversed for PCDFs (and to some extent for PCDDs) with tetra- and penta- chlorinated congeners showing a greater tendency for selective uptake. The overall patterns were consistent, although some variability in BTF values was observed between tested materials which may relate to differences in bioavailability. The results indicate a potentially overlooked source of food chain contamination as other livestock products (cow's milk, lamb, beef, duck, etc.) could be similarly impacted.

A retrospective investigation into the occurrence and human exposure to polychlorinated naphthalenes (PCNs), dibenzo-p-dioxins and furans (PCDD/Fs) and PCBs through cod liver products (1972-2017).

A retrospective analysis of a number of historical medicinal grade cod liver oil samples produced in Northern Europe revealed relatively high contamination levels of PCNs, PCDD/Fs and PCBs. The total toxic equivalence (TEQ) associated with PCDD/Fs, dl-PCBs and PCNs was in the range 95-427 pg g-1 for Baltic cod liver oils and from 70 to 148 pg g-1 for oils sourced from the North Atlantic. The corresponding range for canned cod liver products (Baltic Sea) sampled in 2017 ranged from 52 to 104 pg g-1 fat (33-34 pg g-1 ww). The contribution from PCBs to the overall TEQ toxicity was around 3-6-fold higher than from PCDD/Fs and ranged from 24 to 318 pg TEQ g-1ww. The estimated summed TEQ intakes of PCDD/Fs, dl-PCBs and dl-PCNs resulting from the consumption of the daily recommended doses was highest for the Baltic cod liver oils ranging from 16 to 293 pg kg-1 body mass (bm) day-1 for an adult, 20-183 pg kg-1 bm day-1 for a teenager and 15-131 pg kg-1 bm day-1 for a child. The contribution to daily adult TEQ intake from PCNs alone, although relatively small is estimated to contribute up to 5-fold above the recent EFSA proposed TWI of 2 pg kg-1 bm. The results indicate that although currently produced fish oils may undergo rigorous purification procedures and show low contaminant levels, cod livers sourced from the Baltic and consumed locally, continue to contribute substantially to the dietary intake of these contaminants.

Mixed halogenated dioxins/furans (PXDD/Fs) and biphenyls (PXBs) in food: occurrence and toxic equivalent exposure using specific relative potencies.

The occurrence of nineteen mixed halogenated (bromo-chloro) dibenzo-p-dioxins, dibenzofurans (PXDD/Fs) and biphenyls (PXBs) in a range of foods (n>100) was investigated. The analytical methodology used dual activated carbon column fractionation with high resolution mass spectrometric measurement (13,500-15,000 res). Occurrence was observed in most commonly consumed foods but the most frequent detections of these environmental contaminants were made in shellfish and offal. The concentrations of the individual compounds were condensed into toxic equivalents (TEQs) using recently reported relative potency values. Although representing only a small subset of the full range of toxic PXDD/Fs and PXBs, the TEQs estimated for these compounds ranged from 0.2% to approximately 15% (depending on the food matrix) of the corresponding TEQ for the fully chlorinated analogues. This finding is of great toxicological importance as it implies that a potentially greater magnitude of TEQ could be associated with the full range of toxic PXDD/Fs and PXBs, thus making a significant contribution to dioxin-like toxicity from the diet, to human exposure.

Mixed brominated/chlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls: Simultaneous congener-selective determination in food.

Of the 4600 individual poly-halogenated (bromo-chloro) dibenzo-p-dioxins, dibenzo-furans (PXDD/Fs) and 9180 poly-halogenated biphenyls (PXBs), 19 compounds were selected for analysis in food, based on current toxicological knowledge, chemical configuration, type and degree of halogenation, and the limited knowledge on environmental occurrence levels. The selection was also tempered by the availability of reliable analytical standards. The analytical methodology designed to allow simultaneous determination of PXDD/Fs and PXBs, was based on internal standardisation with (13)C(12) labelled compounds and high resolution mass spectrometry and involved a new separation procedure using dual activated carbon column fractionation. In order to unambiguously measure these compounds a practical, higher mass resolution (13,500-15,000 res) was used, coupled with a judicious choice of analyte ions and relative ion ratios. Further specificity was incorporated by exploiting the differences in chromatographic retention from those of potential interferants. The methodology was validated and used to measure occurrence levels of these contaminants in different matrices such as milk, meat, fish, eggs, offal, shellfish and soil. The limits of detection achieved by this methodology ranged from 0.005 to 0.02ngkg(-1) fat for foods. The analyses revealed the presence of both PXDD/Fs and PXBs, with the latter occurring to a greater extent, followed by PXDFs. This work represents the first targeted approach to measuring a range of individual PXDD/Fs and PXBs simultaneously.

Polychlorinated naphthalenes (PCNs): congener specific analysis, occurrence in food, and dietary exposure in the UK.

Information on the occurrence of toxicologically significant polychlorinated naphthalenes (PCNs) in food, or on human exposure, is sparse. In this work, PCN congeners (PCNs 52, 53, 66/67, 68, 69, 71/72, 73, 74, and 75) were selected for analysis, based on the available literature on current occurrence and toxicology, and limited by the commercial availability of reference standards. The analytical methodology used cold solvent extraction of prehydrolyzed samples fortified with internal standards ((13)C(10) labeled PCNs), activated carbon and basic alumina purification, and measurement by HRGC-HRMS. The investigation showed PCN occurrence in all studied foods: meat, milk, fish, dairy and meat products, eggs, poultry, vegetables, fruits, etc. The most frequently detected congeners were PCN 52, PCNs 66/67, and PCN 73. The highest concentrations were observed in fish (maximum value of 37 ng/kg w.w. for the sum of the measured congeners). The dioxin-like toxicity (PCN TEQ) associated with these concentrations is 1-2 orders of magnitude lower than those reported for chlorinated dioxins or PCBs in food and, on the basis of dietary intakes estimated using very conservative assumptions regarding concentrations of these contaminants in the UK, the levels of PCNs alone in food do not suggest any toxicological concerns.