PBDEs in cod (Gadus morhua) liver products (1972-2017): Occurrence and human exposure

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Feed as a source of polybrominated diphenyl ethers (PBDEs)

One of the most important routes for human exposure to polybrominated diphenyl ethers (PBDEs) is the ingestion of contaminated food. Food of animal origin safety is strongly related to feed quality. The aim of the study was the assessment of feeds and feed materials quality associated with ten PBDE congeners (BDE-28, 47, 49, 99, 100, 138, 153, 154, 183 and 209) contamination. The quality of 207 feed samples divided into eight categories (277/2012/EU) was checked using the gas chromatography-high resolution mass spectrometry (GC-HRMS). At least one congener was identified in 73% of the samples. All investigated fish oil, animal fat, and feed for fish were contaminated, and 80% of plant-origin feed samples were free of PBDEs. The highest median content of ∑10PBDE was found in fish oils (2260 ng kg-1) followed by fishmeal (530 ng kg-1). The lowest median was found in mineral feed additives, plant materials excluding vegetable oil and compound feed. BDE-209 was the most frequently detected congener (56%). All congeners except BDE-138 and BDE-183 were detected in 100% of the fish oil samples. Except for BDE-209, the congener detection frequencies did not exceed 20% in compound feed, feed of plant origin, and vegetable oils. Excluding BDE-209, similar congener profiles were found for fish oils, fishmeal and feed for fish, with BDE-47 in the highest concentration, followed by BDE-49 and BDE-100. Another pattern appeared in animal fat, with a higher median concentration of BDE-99 than BDE-47. Time-trend analysis of PBDE concentrations in fishmeal (n = 75) showed a 63% decrease in ∑10PBDE (p = 0.077) and a 50% decrease in the ∑9PBDE (p = 0.008) between 2017 and 2021. It proves the international legislation implemented to reduce PBDE environmental levels has been effective.

The crosstalk effects of polybrominated diphenyl ethers on the retinoic acid and thyroid hormone signaling pathway

The toxicological and pathological influences of polybrominated diphenyl ethers (PBDEs) on the animal central nervous system have attracted worldwide attention. However, their mechanism of action has not been completely elucidated. Given that retinoic acid (RA) and thyroid hormone (TH) signaling pathway are closely related to neurodevelopment, the crosstalk between the two signaling pathways at the levels of metabolite conversion, gene expression and ligand-receptor interaction after exposure to two representative PBDE congeners (BDE-47 and BDE-209) using zebrafish larvae, dual reporter gene assay, and docking simulation was studied. Our results clarified that BDE-47 could disrupt the transport and metabolism of retinoids, induce changes in expression of key genes, bind with the seven nuclear receptors, and activate RA signaling pathway. BDE-47 exhibited more effects on the indicators of the two signaling pathways than BDE-209. Furthermore, BDE-47 may disrupt TH signaling pathway by disrupting RA signaling pathway, indicating that RA signal is priorly influenced than TH signal. This work offered a new perspective to elucidate TH signal disruption mechanism induced by PBDEs from RA signaling pathway, which is of great significance to elucidate the health effects of PBDEs.

Terrestrial animal livers as a source of PCDD/Fs, PCBs and PBDEs in the diet

The livers of terrestrial animals are an important source of vitamins and minerals, but with the liver being the major filtering and detoxifying organ, it retains xenobiotic material, especially persistent organic pollutants (POPs). The aim of the study was human health risk assessment related to the presence of certain POPs, namely polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in terrestrial animals' livers. HRGC-HRMS was used to determine analyte concentrations in 99 liver samples of chicken, pork, beef, and mutton livers obtained from Polish farms. The ovine livers were the most contaminated by ∑PCDD/F/dl-PCBs (0.06-2.21 pg WHO-TEQ g^-1 wet weight), ∑ndl-PCBs (0.036-1.54 ng g^-1 wet weight) and ∑PBDEs (0.21-2.27 ng g^-1 wet weight). Samples were found of ovine and pork livers that exceeded the maximum concentration limits established for PCDD/Fs. The Kruskal-Wallis test showed that there were statistical differences between regions in the concentrations of the ∑PCDD/Fs and ∑PCDD/F-PCBs, but none in those of the ∑dl-PCBs, ∑ndl-PCBs or ∑PBDEs. According to Dunnett's test results, ovine liver samples from the Podlaskie province contained fewer ∑PCDD/F than those from the Dolnośląskie (p < 0.027) and Małopolskie (p < 0.0342) voivodeships. Taking into account PCDD/F contents and Tolerable Weekly Intake (2 pg WHO-TEQ/kg BW) (TWI₂₀₁₈), the lowest risk was associated with chicken liver consumption (TWI up to 11 % in the 95th percentile), pork (62 %) and bovine (92 %) livers should be eaten in limited amounts for risk avoidance, while mutton liver (400 %) should not be eaten at all. Additionally, there is no risk of ingestion of a harmful amount of PBDEs associated with consumption of the livers of terrestrial animals from Poland based on the margin of exposure values (>15).

Occurrence of some legacy and emerging contaminants in feed and food and their ranking priorities for human exposure

The "feed-to-food" pathway is one of the most important routes for human exposure to manmade contaminants. The contaminants could threaten human health through the "feed-to-food" route and have recently become of great public concern. This review selects the representative legacy and emerging contaminants (ECs), such as polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), organophosphate esters (OPEs), short-chain chlorinated paraffins (SCCPs), and per- and polyfluoroalkyl substances (PFASs), regarding their occurrence in feed and food, as well as their metabolites and transport in farming and livestock ecosystems. Factors that might influence their presence and behavior are discussed. This review raises an approach to rank the priority of ECs using the EC concentrations in feed and food and using the hazard quotient (HQ) method for human health. Although SCCPs have the highest levels in feed and food, their potential risks appear to be the lowest. PFASs have the highest HQs on account of human exposure risk. Future research should pay more attention to the combined effects of multiple ECs.

Human exposure to polybrominated diphenyl ethers (PBDEs) through the diet: An update of the scientific literature

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame-retardants (BFRs). As for other persistent organic pollutants, dietary intake (followed by dust inhalation) is the main route of human exposure to PBDEs. In 2012, we reviewed the scientific literature on the concentrations of PBDEs in foodstuffs and their dietary exposure. The current review is aimed at updating the results of recent studies (2012-2022) focused on determining the levels of PBDEs in food samples, as well as the dietary intake of these compounds. We have revised studies conducted over the world. The current information on the concentrations of PBDEs in food and their dietary intake is now much more notable than that available in our previous review, being China the country contributing with the highest number of studies. Because of the important differences in materials and methods used in the available studies, the comparison of results is certainly complicated. However, there seems to be a general trend towards a decrease in the levels of PBDEs in foods, and consequently, in the dietary intake of these contaminants. The lack of tolerable daily intakes of PBDEs is an issue that needs to be solved for assessing human health risks of these BFRs.

Evaluation of flame retardancy and flexural property on prepared plastic disks containing known concentrations of flame retardants through simulated weathering tests

The standardized acrylonitrile-butadiene-styrene (ABS) or polycarbonate (PC) resin disk with added flame retardants (FRs) has a potential to be a suitable tool for predictions of both aging of the plastic materials and release rate of a flame retardants exposed under different outdoor and indoor conditions. The experiments examined the dynamics and kinetics of the release of dechlorane plus, tetrabromobisphenol A, triphenyl phosphate and antimony trioxide as FRs from a standardized plastic disk before and after exposure to artificial sunlight. Assessments were carried out independently to measure changes in the content of flame retardants and monitor the flame retardancy and flexural properties after exposure (60 W/m²) over a period of 200 h and 500 h, which are reasonable to predict a short-time tendency and to receive any advice for a safe re-use. The releases of three organic flame retardants and four elements (Cl, Br, P and Sb) from weathered ABS and PC disks were very limited, except for surface delamination and resin microparticles. Triphenyl phosphate was stable without hydrolysis, while the degradation of tetrabromobisphenol A was observed (approximately 20% decrease for ABS disk and approximately 50% decrease for PC disk). During the study, no significant differences in the flame retardancy and flexural properties of the disks could be detected. In practice, the results obtained from disks of acrylonitrile-butadiene-styrene or polycarbonate resin with selected flame retardants used in specific conditions may provide technical expertise regarding weathering processes.

Polybrominated diphenyl ethers (PBDEs) in raw milk from different animal species and in infant formula. Occurrence and risk assessment

Polybrominated diphenyl ethers (PBDEs) are widespread, persistent in the environment, and classified as global pollutants. Their presence has been confirmed in various types of food which adversely affect human health when consumed in sufficient amounts. Although milk has advantageous nutritional qualities and there are health benefits associated with its consumption, it could also contain toxic PBDEs. The aim of the study was the determination of the concentrations of ten congeners (BDE -28, -47, -49, -99, -100, -138, -153, -154, -183, and 209) in cow's, sheep's, and goat's milk obtained from Polish farms and their determination in infant formula. A total of 103 samples of raw milk and infant formula were tested using an accredited high-resolution gas chromatography-high-resolution mass spectrometry method. PBDEs were detected in all analyzed samples, the highest concentration being found in sheep's milk (11.9 ng g^-1 fat), and cow's milk containing the least contamination. BDE-209 makes the predominant contribution to the sum of the ten congeners, constituting at least 38%. The profiles of PBDEs were dependent on the milk type and the differences between its varieties are discussed. The highest median concentration of the sum of ten PBDEs (0.473 ng g^-1 fat) was determined in infant formula, which was identified as an important source of infants' exposure (5.48 ng kg^-1 b.w. day^-1 calculated based on P95 concentration). Milk is a source of PBDE in the diet; however, considered in isolation its consumption does not pose a risk to either adults' or children's health.

Polychlorinated naphthalenes (PCNs) in food products in Latvia: Congener-specific analysis, occurrence, and dietary exposure of the general population

A study was performed to evaluate the dietary exposure of the Latvian population to polychlorinated naphthalenes (PCNs). Based on the toxicological characteristics, provisional levels of occurrence, congener patterns, and the availability of analytical standards, twenty-six congeners were included in the analysis. Considering the planar structure of PCNs, an analytical protocol on the basis of destructive clean-up and isolation of analytes on carbon was applied, while GC-HRMS and isotope dilution were used for the detection and quantification of analytes. Commonly consumed foods were analyzed for the content of PCNs, followed by per capita intake calculations. By applying the available in vitro relative potency (REP) factors, putative toxic equivalents (TEQ) were determined, in order to assess the "dioxin-like" effect arising from the presence of PCNs in food. The daily intake (EDI) for total PCNs (∑_PCN) and PCN-TEQ for the general population were calculated to be 116 pg kg^-1 body weight (b.w.) and 0.036 pg TEQ kg^-1 b.w., respectively. Fish and fish products were found to provide the main contribution to the dietary "dioxin-like" burden of PCNs, constituting ∼60% of the total PCN-TEQ intake. For some fish samples, PCN-TEQ could additionally contribute up to ∼3% to the regulated PCDD/F-PCB-TEQ, while for other matrices this contribution could be lower by an order of magnitude. The obtained data indicated that the estimated dietary exposure to PCNs is likely to be of low concern, although PCN-TEQ could be recognized as a contributor to the overall "dioxin-like" TEQ loading that results from the exposure to halogenated aromatics.

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDD), dechlorane-related compounds (DRCs), and emerging brominated flame retardants (EBFRs) in foods: The levels, profiles, and dietary intake in Latvia

This study was performed to assess the Latvian population exposure to polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDD), dechlorane-related compounds (DRCs), and emerging brominated flame retardants (EBFRs). Food items including fish, fish products, meat, dairy products, cereals and bread, eggs, vegetable oils, and sweets were analyzed for the content of these contaminants, followed by per capita intake calculations and risk assessment. The highest dietary exposure for general population was observed in the case of HBCDD, .reaching an estimated daily intake (EDI) value of 2.92 ng kg^-1 b.w. (or 3.35 ng kg^-1 b.w. if an outlying data point is included), followed by PBDEs with EDI of 1.24 ng kg^-1 b.w., including ~25% contribution of PBDE-209 to the overall EDI from PBDEs. DRCs and EBFRs were secondary contributors to the total intake of selected flame retardants (FRs), with the observed EDIs of 0.46 and 0.47 ng kg^-1 b.w, respectively. The obtained occurrence data and risk characterization according to the European Food Safety Authority (EFSA) approach showed the calculated margin of exposure (MOE) values higher than the critical values for PBDE-47, -99 and -153as well as for HBCDD, indicating that the estimated dietary exposures are unlikely to be of significant health concern for the Latvian population. At the same time, it should be pointed out that the risk assessment was performed only for five out of the twenty-five selected halogenated flame retardants (HFRs), while cumulative effects due to the potential presence of other HFRs and their biodegradation products were not considered.

Determinants of flame retardants in non-occupationally exposed individuals - A review

Flame retardants (FRs) constitute a large group of different substances, some of which have been phased out of the market due to health concerns, while others are still used in many common consumer products to prevent fire hazards. This review addressed the determinants of FRs in non-occupationally exposed individuals based on surveys and questionnaire data. For this literature review, three databases (Scopus, Pubmed and Web of Knowledge) were searched by applying suitable terms, inclusion and exclusion criteria, producing a final selection of 78 articles for review. Based on these surveys there is epidemiological evidence for a significant association (p < 0.05) among human exposure and demographic factors, as well as a significant correlation between exposure to FRs and behavioural and environmental factors. Age, gender, housing characteristics, electrical and electronic equipment and mouthing behaviour (in children) play a leading role in human exposure to FRs as published studies demonstrated. However, the methodological differences among studies such as population size, questionnaire design and statistical analysis did not reveal a complete pattern of human exposure routes. Risk perception and communication are also discussed based on limited available data. Knowledge gaps and future perspectives relating to standardized protocols, elucidation of contamination sources, and risk response of health information from different target groups were also identified.

Polybrominated dibenzo-p-dioxins (PBDDs) and - dibenzofurans (PBDFs) in cod (Gadus morhua) liver-derived products from 1972 to 2017

Literature data on the occurrence and prevalence of polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs) in foods including seafood are scarce. In this study, a number of cod-derived products including medicinal grade cod liver oils sourced from Northern Atlantic waters (Iceland, Norway) and the Baltic Sea (Poland) during 1972-2001 and canned cod liver sourced from the Baltic Sea in 2017, showed detectable levels of PBDFs: such as 2,3,8-TrBDF at 0.57 to 5.249 pg g^-1 fat and 1,2,3,4,6,7,8-HpBDF at <0.018 to 0.302 pg g^-1 fat. PBDDs were not detected in the cod liver oils. Canned cod liver products showed low levels of 2,3,7,8-TeBDD in the range <0.017 to 0.022 pg g^-1 whole weight and 1,2,3,7,8-PeBDD at <0.03 to 0.039 pg g^-1 whole weight. These concentrations were computed to yield upper bound toxic equivalences (TEQs) of 0.14 to 0.17 pg g^-1 for the oils and 0.12 to 0.25 pg g^-1 for the canned products (0.08 pg g^-1 ww for both products). The resulting supplementary and dietary intakes are low (0.02 to 0.11 pg kg^-1 bm day^-1 for the oils and 0.07 to 0.17 pg kg^-1 bm week^-1 for the canned livers) in comparison to the recently expressed tolerable weekly intake of 2 pg kg^-1 bm week^-1. However, the intakes are underestimates, as due to a lack of analytical standards not all PBDD/F TEQ contributing congeners could be included. The PBDD/F TEQ contributes to the cumulative toxicity arising from other contaminants such as chlorinated dioxins and polychlorinated biphenyls.

Dioxin-like polybrominated biphenyls (PBBs) and ortho-substituted PBBs in edible cod (Gadus morhua) liver oils and canned cod livers

This study investigates the occurrence of polybrominated biphenyls (PBBs), a legacy flame retardant, in fishery products such as medicinal grade cod liver oils and canned liver products, sourced from the North Atlantic during 1972-2017. It also assesses the dietary and supplementary (the oils were commonly administered as dietary supplements to children and youth) intake of PBBs from these products. Summed ortho-PBB concentrations ranged from 770 to 1400 pg g^-1 fat in the oils and from 99 to 240 pg g^-1 whole weight in canned livers, with PBB-49, 52, 101 and 153 accounting for most of these levels. Among the more toxic non-ortho-PBBs, PBB-126 and PBB-169 were not detected, but PBB-77 concentrations ranged from 0.6 to 5.78 pg g^-1 fat in the oils and 0.06-0.126 pg g^-1 whole weight in canned livers. During 1972-1993, PBB contamination levels were similar for cod liver oils from the Baltic Sea and other North Atlantic regions, but over the timescale of the study, Baltic Sea products appear to show a decline in PBB concentrations. As PBB-77 was the only dioxin-like PBB detected in the samples, the corresponding supplementary (oils, 1972-2001) and dietary (cod liver from 2017) intakes were very low, at < 0.001 pg TEQ kg^-1 bm d^-1 (or < 0.01 pg TEQ kg^-1 bm d^-1 upper bound) for the sum of all the measured dioxin-like PBBs -four to six orders of magnitude lower than that arising from other dioxin-like contaminants that were shown to occur in these products, from earlier studies.

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.