Uptake of polychlorodibenzo-p-dioxins, polychlorodibenzofurans and coplanar polychlorobiphenyls in chickens

Polychlorinated dibenzo-p-dioxin and dibenzofuran contamination of free-range eggs: estimation of the laying hen's soil ingestion based on a toxicokinetic model, and human consumption recommendations

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are ubiquitous in the environment. The main route of human exposure is through food consumption. Soil contamination can be problematic for sanitary safety depending on the usage of the soil, such as farming. In case of environmental soil contamination with PCDD/Fs, hen's eggs may be contaminated due to soil ingestion by hens. For this reason, it is important to understand the parameters that influence eggs' contamination when hens are raised in contaminated areas. After the discovery of a contaminated area in Lausanne (Switzerland), we collected hens' eggs from ten domestic-produced eggs and one farm. Based on PCDD/F measurements of eggs and soil, and a toxicokinetic model, we estimated individual hen's soil intake levels and highlighted appropriate parameters to predict the dose ingested. Recommended weekly consumption for home-produced eggs was calculated based on the tolerable weekly intake proposed by EFSA in 2018. The most important parameter to assess the soil ingestion does not seem to be the soil coverage by vegetation but rather the hen's pecking behaviour, the latter being difficult to estimate objectively. For this reason, we recommend using a realistic soil ingestion interval to assess the distribution of egg PCDD/F concentration from free-range hens reared on contaminated soil. The addition of soil contamination in the toxicokinetic model can then be used to recommend to the general population weekly consumption of eggs. The consumption by adults of free-range eggs produced on land with soil containing >90 ng toxic-equivalent (TEQ)/kg dry soil should be avoided. Even with a low level of soil contamination (1-5 ng TEQ/kg dry soil), we would recommend consuming not more than 5 eggs per week for adults and no more than 2 eggs for children below 4 years old.

Generic methodology to prevent food contamination by soil born legacy POPs in free range livestock

Government monitoring commonly includes regulating POPs in animal feed and products of animal origin, with many countries setting Maximum Residue Levels (MRLs) to ensure safe tolerable concentrations. However, these MRLs do not address the presence of most POP families in soil, where concentrations can be much higher due to the contaminants' strong affinity and persistence in comparison to other environmental matrices. Extensive damage to food and production systems during a pollution incident causing soil contamination by POPs lead to severe economic and social consequences for the affected area. To mitigate these effects, it is crucial to implement necessary measures for consumer protection while also focusing on rehabilitating conditions for food production, tailored to both commercial farms and private holders. In this context, the present work aims to develop and test a methodology for assessing the tolerable concentration of the most cancerogenic legacy POPs in soil for various livestock animals in diverse rearing systems ensuring the safety of food of animal origin. Therefore, we summarize existing knowledge about the risk of POP transfer in different livestock breeding systems via soil exposure, and modeling via a backward calculation from the MRLs the corresponding tolerable quantity of POPs that may be ingested by animals in the considered rearing system. Results of these simulations showed that soil ingestion is a predominant contamination pathway, which is a central factor in the risk assessment of POP exposure on livestock farms, especially in free-range systems. In field conditions of POP exposure, low productive animals may be more susceptible to uptake through soil than high-yielding animals, even if the feed respected MRLs. Results show that PCDD/Fs revealed the lowest security ratio for low productive dairy cows (1.5) compared to high productive ones (52). Laying hens with a productivity of 45% show also as a high sensitivity to POPs exposure via soil ingestion. Indeed, their security ratio for PCDD/Fs, lindane and DDT were 3, 2 and 1, respectively. In perspective, proposed methodology can be adapted for assessing the risk of industrial POPs newly listed in the Stockholm Convention. In practice, it could be useful for food producers to apprehend their own risk of chemical contamination.

Kinetics of PCDD/Fs from feed to cow milk and its implications for food safety

Guideline levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in feed and food have been separately recommended for the official food safety control around the world. However, less is considered about the transfer effect of PCDD/Fs from feed to food, and consequently possible human exposure risk. In this study, different controlled feeding experiments (E1 group: 4.92 pg TEQ/g in feed, E2 group: 0.61 pg TEQ/g in feed) were conducted on dairy cow (Chinese Holstein breed) to evaluate kinetics of PCDD/Fs from feed to milk and blood. Even though the PCDD/F level in feed in E2 was satisfied with the EU Regulation (No 277/2012), the TEQ levels in milk and tissues exceeded the European Union maximum level (EU ML) after approximately one-week exposure. The dynamic variation in milk during the initial 20-day exposure was successfully described by a first-order kinetic model. The levels at the plateau period showed a significant linear relationship (p < 0.01, R² = 0.98) against the intake amounts from feed. Based on modeling, a maximum content was obtained at approximately 0.33 pg TEQ/g in cow feed with 12 % moisture to ensure the milk and meat safety under the current regulatory requirements of EU for cow-origin food. After the cease of exposure, the PCDD/F levels in milk declined below the EU ML within 40 days, while those in meat were still higher than the EU ML over 160 days. In serum, PCDD/Fs detected in E1 showed a similar dynamic variation during the exposure period. Regarding congener profile, higher-chlorinated congeners tended to transfer from feed to feces, whereas lower ones were preferably transferred into milk, which required specific concern about the metabolic effect of PCDD/Fs in large mammals. This study revealed a necessity for re-evaluation of official regulation on pollutants in cow feed and cow-origin food in terms of biotransfer and bioaccumulation.

In-silico analysis of atmospheric diffusion, crop planting degrading scheme, and health risk of dioxins from a domestic waste incineration plant

Based on a domestic waste incineration power generation project, the dioxin emission from the waste incineration plant (WIP), phytoextraction and microbial degradation of dioxins, and dioxins human health risks reduction were investigated through in-silico methods. Based on the dioxins concentrations in soil (9.97 × 10^-9-7.00 × 10^-5ng/g) predicted by atmospheric dispersion model system and the Level-III fugacity model, planting schemes under different wind directions were designed considering the dioxin absorption capacity and the economic benefits for crops (i.e., barley, peanut, pea, maize and wheat). The dioxins in soils can be further degraded by five crops' rhizosphere microorganisms and fertilizers, simulated through molecular dynamic simulations. The enhanced degradation rates of dioxin by rhizosphere microorganisms of five crops reached 15.70 %-28.66 %. Finally, healthy dietary plans were developed to reduce the risk of dioxin exposure to the sensitive populations living around WIP. Results showed that the consumption of maize, fungus, mushroom and bamboo fungus could effectively reduce dioxins toxicity to humans by 58.13 %. The systematic approach developed in this study provided theoretical support for soil remediation and human health risk control of dioxins-contaminated sites.

Engine oil from agricultural machinery as a source of PCDD/Fs and PCBs in free-range hens

Free-range hens spend most of their lives outdoors, resulting in their heavy exposure to environmental pollutants such as polychlorinated dibenzo-p-dioxin, dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and non-dioxin-like polychlorinated biphenyls (NDL-PCBs). We present a case of contamination of free-range eggs that is previously unreported in the literature. The aim of our study was a source investigation after finding a high level of PCDD/Fs in samples of eggs from one of the inspected farms. Samples of hens' eggs, muscles, and livers and the feeds and soils were analyzed. The results showed that the soil samples taken from the paddock contained high concentrations of PCDD/Fs and DL-PCBs expressed as toxic equivalents (TEQ) (72.9 ± 18.2 pg WHO-TEQ g^-1 dry mas (d.m.)) and a high concentration of NDL-PCBs (207 ± 46.9 ng g^-1 d.m.). The investigation found that the cause of the soil contamination was oil leaking from the farm's tractor engine. The oil contained very high concentrations of PCDD/F and DL-PCBs (1013 ± 253 pg WHO-TEQ g^-1 oil) and 5644 ng g^-1 of NDL-PCBs. The source of the contamination was confirmed by the similarity of the PCDD/F and PCB profiles in the hen eggs and the soil contaminated by engine oil. The dietary intake of toxins resulting from consumption of the eggs is provided. For children, the consumption of contaminated eggs would result in an intake of double the tolerable weekly intake (TWI), while for adults, it would be approx. 60-70% of TWI.

Bioaccumulation of PCDD/Fs and PCBs in free-range hens: Congener fingerprints and biotransfer factors

The bioaccumulation of lipophilic environmental contaminants in farm animals is an important issue to control and prevent human exposure to toxic pollutants. Free-range hens were used as a model to assess the transfer and the bioaccumulation of PCDD/Fs, DL-PCBs and NDL-PCBs from the soil to eggs in an area in the Campania region particularly affected by pollution, the "Land of Fires". We determined the following ranges of concentrations in eggs: 0.90-5.51 pg WHO-TEQ g^-1 fat for PCDD/Fs; 1.63-4.24 pg WHO-TEQ g^-1 fat for DL-PCBs; 2.77-9.75 pg WHO-TEQ g^-1 fat for the sum of PCDD/Fs and DL-PCBs and 12.53-30.94 ng g^-1 fat for NDL-PCBs. Higher contamination levels were observed in the eggs from free-range hens, compared to those of the control group, that is hens raised indoors; this indicates that soil remains a major source of contamination. Livers showed low levels of contamination for both outdoor and indoor reared hens. Biotransfer factors (BTFs) were calculated for each of the 35 PCDD/F and PCB congeners analysed. The BTFs highlighted that the transfer and bioaccumulation depend on chlorination degree and substitution pattern, in particular they increase with increasing chlorination degree up to the hexa-chlorinated congeners and then decrease. An exception to these finding was observed for 2,3,7,8 TCDD and 2,3,7,8 TCDF, which showed very high BTFs. These results demonstrate the importance of promoting studies on the environmental contaminants bioaccumulation as they provide an effective support for the risk assessment and management of exposure to toxic chemicals.

Toxicokinetic Modeling of the Transfer of Non-Dioxin-like Polychlorinated Biphenyls (ndl-PCBs) from Feed and Soil into Laying Hens and Their Eggs

Non-dioxin-like polychlorinated biphenyls (ndl-PCBs) are a subclass of persistent bioaccumulative pollutants able to enter the food chain. Toxicokinetic models for the transfer of the six ndl-PCB congeners (PCBs 28, 52, 101, 138, 153, and 180) from contaminated feed and soil into chicken eggs and meat are presented. Three independent controlled feeding study datasets were used to estimate the model parameters and four studies for evaluating the model performance. The yolk deposition of ndl-PCBs is modeled in a novel way that mimics the physiology of yolk growth and development, resulting in improved prediction of the experimental data without introducing an ad hoc time delay between ovulation and oviposition. Using the models, the highest level of 2.4 μg/kg dry matter (DM) was calculated for the sum of ndl-PCBs in laying hen feed to ensure that the current maximum levels in meat and eggs (40 ng/g fat) will not be exceeded. It is also shown how this highest level in feed should be adapted in case soil, in addition to feed, is also a source of ndl-PCBs for free-range chickens.

A pilot evaluation on the toxicokinetics and bioaccumulation of polychlorinated naphthalenes in laying hens

Knowledge of the transfer features of polychlorinated naphthalenes (PCNs), a class of emerging persistent organic pollutants (POPs), is still lacking concerning the environment-feed-food transfer chain of farm animals. We conducted a controlled feeding experiment with laying hens fed fly ash-contaminated diets to investigate the toxicokinetics and bioaccumulation of PCNs (tri- to octa-CNs) in the hen eggs and tissues. The eggs showed increasing PCNs levels after 14 days of oral exposure, which gradually decreased during the 28-day depuration period but still exceeded the initial levels. The apparent one-compartment half-life of ∑₆₃PCNs in the eggs was 28.9 days, which was comparable to those of other dioxin-like compounds. The uptake and depuration rates of PCN congeners in the eggs were 0.002-0.010 and 0.016-0.079 days^-1 in eggs, respectively. The depuration rates were decreased with the n-octanol/water partition coefficients (logK_OW), indicating that the eggs retained more lipophilic congeners, whereas the uptake rates increased with the logK_OW, indicating the faster deposition of the more lipophilic PCNs in eggs during the exposure period. The transfer rates of PCN congeners ranged from 0.27%-23.0%, indicating the transfer potential of PCNs from feed to eggs. Additionally, the PCN distribution in the laying hens at the end of the exposure showed tissue-specific accumulation, with the high levels of PCNs in the liver, spleen, and ovum. Positive correlations between the transfer factors (C_tissue/C_feed) and the logK_OW suggested that more lipophilic PCN congeners tended to accumulate in the tissues. After quantitatively assessing the feed-to-food transfer of PCNs in laying hens, our results highlight the risk of exposure to PCNs in the food supply chain.

Insights into the toxicokinetic, tissue distribution and maternal transfer of polychlorinated dibenzo-p-dioxins/dibenzofurans in laying hens fed with dioxin-associated dietary

A controlled feeding experiment was conducted to investigate the toxicokinetic of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in laying hens. The laying hens were fed with fly ash contaminated diets to replicate the typical environment-feed-chicken transfer chain in China. Levels of PCDD/Fs rapidly increased in the pectoralis, adipose tissue, liver and blood of laying hens with daily ingestion of dioxin-associated diets during the 14-days exposure period, and then a gradual decrease was observed in the 28-days depletion period. The depletion rates (k_d) of the toxic equivalent of PCDD/Fs (TEQ_PCDD/Fs) were 0.043, 0.031 and 0.030 day^-1 for pectoralis, liver and adipose tissue in the high-exposure group, respectively. The k_d of individual PCDD/Fs in liver increased with the numbers of chlorine and n-octanol/water partition coefficient (logK_OW), indicating that lower chlorinated congeners had higher half-lives in liver. Decreasing ratios of liver to adipose tissue for PCDD/Fs (L/AT) throughout the experiment suggested a tendency of equilibrium partitioning between liver and adipose tissue. Congener-specific sequestration of PCDD/Fs in liver was revealed by the positive correlation between L/AT ratios and logK_OW. Physiological bioconcentration factors of PCDD/Fs were estimated at the end of exposure, indicating the preferential accumulation of hexachlorinated congeners in most tissues. Furthermore, maternal transfer of PCDD/Fs was positively correlated with logK_OW, implying that more lipophilic congeners were transferred to egg along with the lipid circulation.

Reevaluation on accumulation and depletion of dioxin-like compounds in eggs of laying hens: Quantification on dietary risk from feed to egg

Updated assessment on transfer of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) from feed to food is essential for understanding human exposure risk. A controlled feeding experiment was conducted for laying hens to reevaluate the transfer characteristics of dioxin-like compounds from feed to egg. Two fortified diets (1.17 and 5.13 pg TEQ g^-1 dry weight), made by blending with fly ash, were fed to laying hens for 14 days, followed by 28-days depletion. Levels of ∑TEQ_{PCDD/Fs+DL-PCBs} in eggs rapidly increased once exposure started, reaching at 1.98 and 6.86 pg TEQ g^-1 lw at the end of exposure for low- and high-exposure groups, respectively, and dropped to under the European legislation (maximum levels: 5.0 pg TEQ g^-1 lw) after 28-days depletion. The quantitative depletions showed that the half-lives (T_1/2) of ∑TEQ_PCDD/Fs in eggs were 23 and 14 days for low- and high-exposure groups, respectively. The depletion and accumulation rates of PCDD/Fs were in the range of 0.026-0.151 and 0.005-0.016 day^-1, respectively, representing that the T_1/2 of PCDD/Fs in eggs ranged from 5 to 27 days. The depletion kinetics of DL-PCBs was not significant in egg. The hens with higher laying rates exhibited shorter T_1/2 of PCDD/Fs, implying that increasing laying rate could expedite the depletion of PCDD/Fs in egg. The T_1/2 of PCDD/Fs in egg were negatively correlated with the chlorine number, indicating that lower chlorinated congeners tended to be retained in the egg. Transfer rates of PCDD/Fs were in the range of 4-19%, which were lower than the previous results. These results were attributed to short exposure time and low bioavailability of PCDD/Fs in fly ash. Estimations of dietary intake highlighted the dietary risk of PCDD/Fs from feed to egg, which would pose limited adverse effects on human health.

Unraveling Congener-Specific Transfer of Non-Dioxin-Like Polychlorinated Biphenyls (ndl-PCBs) from Feed into Chicken Meat

Non-dioxin-like polychlorinated biphenyls (ndl-PCBs) are a subclass of persistent bioaccumulative pollutants able to enter the food chain. We investigated the transfer of ndl-PCBs from contaminated feed into meat and liver of fattening chickens. A total of 48 chicks were divided into five treatment and one control groups. Treated animals were fed with contaminated diets (11.7 ± 0.4 μg/kg sum of indicator ndl-PCBs; 88% dry matter (DM)) before slaughter for different subperiods of time: 16, 23, 28, 32, and 36 days for groups 1-5, respectively. One day after the end of each subperiod, three animals per group were slaughtered to determine the congener-specific ndl-PCB content. All remaining animals were fed the control feed until slaughter on day 37 to probe depuration. We used these data to generate congener-specific physiologically based toxicokinetic (PBTK) models for indicator ndl-PCBs. The models show that PCBs 28, 138, 153, and 180 form a more slowly eliminated cluster (with an observed transfer rate into meat over 74% and observed half-lives over 8.7 days) than PCBs 52 and 101 (with a transfer rate under 13% and half-lives under 2.6 days). Our simulations show that ndl-PCB levels in feed lower than 3.9 (long 56-day) or 4.4 μg/kg (short 37-day fattening period) would be necessary to ensure the current maximum level in muscle meat (fat basis), according to EU Regulations 1881/2006 and 1259/2011. The PBTK models are made available in the Python and Food Safety Knowledge Exchange formats.

Accumulation of short-, medium-, and long- chain chlorinated paraffins in tissues of laying hens after dietary exposure

Reliable human health risk assessment associated with chlorinated paraffins (CPs) exposure is limited by the lack of data on the fate of this complex family of contaminants. To gain knowledge on the accumulation and distribution of CPs in biota after ingestion, laying hens were dietary exposed to technical mixtures of short- (SCCPs), medium- (MCCPs), or long-chain (LCCPs) CPs of various chlorine contents during 91 days, at 200 ng/g of feed, each. Adipose tissue, liver, muscle and serum were collected at the steady-state, along with excreta. All C₁₀-C₃₆ CPs were detected in liver. However, differences were observed in CP distribution: LCCPs high %Cl were retained in the liver; LCCPs low %Cl circulated through the serum and were distributed in the different compartments, but were mostly excreted through the eggs; SCCPs and MCCPs were found in all tissues at similar levels. Finally, a mass balance indicated a potential for biotransformation.

Transfer of persistent organic pollutants in food of animal origin - Meta-analysis of published data

The transfer of POPs in food of animal origin has been studied by a meta-analysis of 28 peer-reviewed articles using transfer rate (TR) for milk and eggs and bioconcentration factors (BCF) for eligible tissues after establishing an adapted methodology. TRs of the most toxic PCDD/Fs into milk were generally elevated and even higher into eggs. BCFs in excreting adult animals varied widely between studies complicating to hierarchize tissues or congeners, even if liver and fat seemed to bioconcentrate more than lean tissues. Short time studies have clearly shown low BCFs contrarily to field studies showing the highest BCFs. The BCFs of PCDD/Fs in growing animals were higher in liver than in fat or muscle. In contrast to easily bioconcentrating hexachlorinated congeners, octa- and heptachlorinated congeners barely bioconcentrate. PCB transfer into milk and eggs was systematically high for very lipophilic congeners. Highly ortho-chlorinated PCBs were transferred >50% into milk and eggs and even >70% for congeners 123 and 167 into eggs. BCFs of the most toxic PCBs 126 and 169 were significantly higher than for less toxic congeners. BCFs seem generally low in PBDEs except congeners 47, 153 and 154. DDT and its metabolites showed high bioconcentration. Differences between tissues appeared but were masked by a study effect. In addition to some methodologic recommendations, this analysis showed the high transfer of POPs into eggs, milk and liver when animals were exposed justifying a strong monitoring in areas with POP exposure.

Tissue distribution and maternal transfer of persistent organic pollutants in Kentish Plovers (Charadrius alexandrines) from Cangzhou Wetland, Bohai Bay, China

Several persistent organic pollutants, including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), were comprehensively investigated in the egg, muscle and liver samples of Kentish Plover (Charadrius alexandrines) collected from Cangzhou Wetland in western Bohai Bay, China. DDTs were the most abundant contaminants (35.4-9853ngg^-1 lipid weight, lw), followed by HCHs, PCBs, PBDEs and HCB. PCDD/Fs exhibited the lowest concentrations in all tissues (8.74-4763pgg^-1 lw). PCBs and PCDD/Fs were dominated by penta- and hexa-homologs, and PBDEs mostly consisted of the signature congeners of BDE formulations, such as BDE-209, -47, -153 and -99. Significant correlations were found between the lipid-normalized concentrations in muscle and liver (r: 0.37-0.90, p<0.05) and no significant differences (p<0.05), indicating the homogenous distribution of POPs in tissue lipids at steady state. The ratios of concentrations in muscle and liver (M/L) ranged from 0.20 to 1.51, and higher ratios of M/L were found for those compounds with log K_ow in the range of 6.5-7.0, suggesting the preferential accumulation of mid-halogenated compounds in muscle. Significant correlations were generally observed between the concentrations in egg and the maternal tissue (p<0.05). The concentration ratios of egg to liver (E/L) were in the range of 0.10-1.24 except for p,p'-DDT (12.7), and compounds with log K_ow of 6.5-7.0 exhibited higher E/L ratios, suggesting the selective maternal transfer of mid-halogenated compounds.

Intake, distribution, and metabolism of decabromodiphenyl ether and its main metabolites in chickens and implications for human dietary exposure

Diet is considered as the most important human exposure pathway for polybrominated diphenyl ethers (PBDEs). Metabolism and accumulation patterns of PBDEs in different growth periods of chickens are helpful for evaluating human dietary exposure, but such information is scarce. In this study, female chickens were fed with food spiked with BDE-209 at 85 mg kg^-1, and the intake, accumulation, and excretion of BDE-209 and its main metabolites in various tissues were examined. Concentrations of BDE-209 in chicken tissues increased over time in a tissue-specific manner; they were the greatest in liver and generally the lowest in breast meat during the entire exposure period. The kinetic patterns were dependent on both growth-dilution effects and accumulated concentrations of BDE-209. Tissue concentrations of ∑₈PBDE (sum of BDE-28, 47, 99, 100, 153, 154, 183, and 209) followed the sequence of liver > blood > skin > intestine > stomach > leg meat > breast meat. Different tissue partition coefficients and perfusion rates for blood may have resulted in different PBDE concentrations in tissues. The absorption efficiency of BDE-209 in chicken tissues followed the sequence of liver (0.15 ± 0.032%) > skin (0.14 ± 0.038%) > intestine (0.071 ± 0.021%) > breast meat (0.062 ± 0.020%) > leg meat (0.059 ± 0.016%) > stomach (0.021 ± 0.0095%), likely due in part to facilitated absorption of BDE-209 by transport proteins (P-glycoproteins). On average, 9.3 ± 1.7% of BDE-209 was excreted in feces. Estimated human average dietary intake via the consumption of chicken tissues of ∑₈PBDE for adults and children was 319 and 1380 ng day^-1 for liver, 211 and 632 ng day^-1 for leg meat, and 104 and 311 ng day^-1 for breast meat from the contaminated group. Liver clearly poses the highest exposure risk for human consumption, particularly if chickens are fed with contaminated feed.

A simple and effective approach for catalytic reductive dechlorination of aromatic compounds

An efficient process for the preparation of 2(3),9(10),16(17),23(24)-octa(n-hexyl)cobalt(II)phthalocyanine, ((n-hexyl)8CoPc) (2) was described. The novel cobalt(II)phthalocyanine was characterized by spectroscopic methods. It was employed as a catalyst for the room temperature reductive dechlorination of chlorinated aromatic compounds (CACs). The results were showed that the CACs were completely dechlorinated within 110–120 min.

In ovo uptake, metabolism, and tissue-specific distribution of chiral PCBs and PBDEs in developing chicken embryos

Fertilized chicken eggs were injected with environmental doses of 4 chiral polychlorinated biphenyls (PCBs) and 8 polybrominated biphenyl ethers (PBDEs) to investigate their uptake, metabolism in the embryo, and distribution in the neonate chicken. PCB95 uptake was the most efficient (80%) whereas BDE209 was the least (56%). Embryos metabolized approximately 52% of the PCBs absorbed. Though some degree of metabolism in the first 18 days, most of the PCBs and PBDEs was metabolized in the last three days, when BDE85, 99, 153, and 209 decrease by 11–37%. Enantioselective metabolism of the (+) enantiomers of PCB95, 149, and 132 and the (−) enantiomer of PCB91 was observed. The enantioselective reactivity was higher with the two penta-PCBs than the two tetra-PCBs. Liver, exhibited high affinity for high lipophilic chemicals, enrich all chemicals that was deflected in other tissues except for some special chemicals in a given tissues. Lipid composition, time of organ formation, and metabolism contribute to the distribution of chemicals in the neonate chicken. The result of this study will improve our understanding on the fate and potential adverse effects of PCBs and PBDEs in the neonate chicken.

Increase of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in human milk from China in 2007-2011

A national survey was conducted to determine polychlorinated dibenzo-p-dioxins and dibenofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in human milk samples collected from 16 provinces in China to assess current exposure and temporal trends in China. The arithmetic mean concentration of total TEQ (PCDD/Fs and dl-PCBs) in 2011 is 6.7pgTEQg^-1 lipid with a range of 2.9-15.4pgTEQg^-1 lipid in 2011. Levels have been compared to data obtained during a previous national study conducted in 2007. The mean of PCDD/Fs has increased about 32.6% and 99.9% for total TEQ concentration (3.7pgTEQg^-1 lipid in 2007 vs 4.9pgTEQg^-1 lipid in 2011) and mass concentration (66.7pgg^-1 lipid in 2007 vs 133.3pgg^-1 lipid in 2011) during the period of 2007-2011, respectively. Continuous surveillance on PCDD/Fs and dl-PCBs in human milk is critical to evaluate the human health effect and environment impact in China.

Human dietary exposure and levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs) and non-dioxin-like polychlorinated biphenyls (NDL-PCBs) in free-range eggs close to a secondary aluminum smelter, Northern Italy

PCDD/Fs and PCBs are environmentally persistent substances that have been associated with adverse effects on human health. Contamination of soils, animal feed and pastures leads to their bioaccumulation of in food products of animal origin, which are considered the major source of intake of these contaminants in humans. We analyzed eggs from free-range hens, sampled from small farms, located within a distance of 4.5 km from a secondary aluminum smelter in Northern Italy. The concentrations of PCDD/Fs, DL-PCBs and NDL-PCBs were higher in eggs from locations close to the plant, and strongly exceeded the limits set by EU Regulation 1259/2011 (2.5 pg WHO TEQ fat g(-1) for PCDD/Fs, 5.0 pg WHO TEQ g(-1) for PCDD/Fs and DL-PCBs L, 40 ng g(-1) for NDL-PCBs). Without the prompt and immediately applied control strategies, the consumption of contaminated eggs may have posed [corrected] a risk for human health, especially for children (≤9 years) and infants (≤3 years), due to the 2-fold excess of the current exposure limits.

High levels of dioxin-like PCBs found in organic-farmed eggs caused by coating materials of asbestos-cement fiber plates: A case study

During a regional monitoring project of organic-farmed, free-range and cage-free eggs, high levels of dioxin-like compounds were detected in organic-farmed eggs, using the dioxin responsive chemical-activated luciferase gene expression (DR-CALUX®) bioassay. Further evaluations performed with GC-HRMS (gas chromatography in combination with high resolution mass spectrometry) revealed elevated amounts of non-dioxin-like (non-dl) polychlorinated biphenyls (PCBs) dominated by most lipophilic congeners like PCB 138, 153 and 180 and of dioxin-like (dl) PCBs, with a congener pattern in the descending order of PCB 118, 156, 167, 105, 189, 157, 105, 126 and PCB 77. Contaminations with polychlorinated dibenzo-p-dioxins (PCDDs) appeared of minor priority, with only hepta- and octa-substituted dioxins above their limits of quantification (LOQs). The pattern of polychlorinated dibenzofurans (PCDFs) was dominated by low amounts of tetra- and penta-chlorinated congeners. To identify the source of contamination, several samples of organic-farmed eggs, soil, laying hens, feedstuff, corrugated asbestos-cement cover plates (ACPs), stable dust and debris collected in the gutter of the stable, were analyzed. Comparing PCB congener-pattern of individual samples, the source was traced back to the coating of ACPs, which covered roof and sidewalls of the stable. Because coating materials probably have been used for roofing and cladding in many countries worldwide, there is a high probability that the presented case report is not a local incident but rather describes a new source of PCB contamination, yet widely unknown or underestimated.

Contaminant sources, gastrointestinal absorption, and tissue distribution of organohalogenated pollutants in chicken from an e-waste site

Several organohalogenated pollutants (OHPs), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) were examined in chicken dietary sources (soil and feed) and gastrointestinal contents (chyme, intestinal contents, and feces), and in 11 chicken tissues (liver, muscle, heart, lung, fat, brain, stomach, intestine, ovary/testis, kidney, and serum) from an e-waste recycling site in South China. Elevated levels of OHPs were found in the soil and chicken tissues. Soil was a more important source of OHPs, especially brominated flame retardants, than feed. In general, more-halogenated chemicals were less readily absorbed in the gastrointestinal tract. With the exception of the brain and serum, where lower concentrations occurred, no significant differences in PCBs, PBDEs, and BTBPE were found among the chicken tissues. DBDPE was detected mainly in the stomach, intestine, kidney, and ovary. Compared with the soil, all the tissues had lower proportions of CBs 52 and 101. PBDEs were dominated by BDE 209 in the soil and chicken feed; two different PBDE congener profiles, dominated by both BDE 183 and BDE 209 or dominated by BDE 209 only, were found in the chicken tissues except for the brain. Only BDE 47 or BDE 209 was occasionally detectable in the brain. DBDPE was also found in the brain samples despite its high log Kow values. The blood-brain barrier alters patterns of contaminant composition and results in lower levels of OHPs in the brain.

Chiral polychlorinated biphenyls (PCBs) in bioaccumulation, maternal transfer, and embryo development of chicken

Polychlorinated biphenyls (PCBs) and enantiomer fractions (EFs) of PCB enantiomers (PCBs 95, 132, 135, and 149) were investigated in soil and chicken feed, chicken (Gallus domesticus) tissues, eggs on 0, 7, and 14 days after the onset of incubation, and newborn chick tissues. The EF values of PCBs 95, 132, and 149 changed significantly from soil to chicken tissues, and the values in the liver exhibited the highest deviation from the racemic ratio, indicating enantiomer-selective metabolism in hens. Congeners, which are highly resistant to degradation, such as PCBs 138, 153, and 180, exhibited the highest maternal transfer potentials when muscle and liver were used to assess the maternal transfer. However, uniform transfer ratios were observed for most of the PCB congeners when visceral fat was used. The EFs of chiral PCBs in eggs either did not match with muscle or with liver or were similar to those in visceral fat. These results indicate that hens mainly mobilized visceral fat for egg formation and PCBs were deposited in eggs by associating with these lipid materials. Further enantiomeric enrichment of PCBs 95, 132, and 149 occurred in the newborn chick tissues. However, an opposite enantioselectivity for PCB 135 in newborn chicks was observed. These results indicate that the potential toxicity of PCB enantiomers to newborn chicks may be different from that of adults.

Accumulation and elimination of polychlorinated dibenzo-p-dioxins and dibenzofurans in mule ducks

In Taiwan, a food safety crisis involving a presence of high concentrations of dioxin residues in duck eggs occurred in 2004. The dioxin content in duck meat sampled from supermarkets was also reported to be substantially higher than in products from other farm animals. Despite increased awareness of the potential for contamination and exposure to dioxins, the accumulation and elimination of dioxins in ducks have not been well characterized. In the present study, mule ducks were fed capsules containing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for 14 days and the trial was continued for another 28 days without PCDD/Fs supplementation. Ducks were sacrificed on the 14th, 28th, and 42nd days from the beginning of administration and samples of abdominal fat, breast, and liver tissue were obtained. The concentrations of PCDD/Fs were analyzed in the samples to investigate their distribution and elimination in various duck tissues. The bioaccumulation of PCDD/Fs in ducks was found to be tissue-dependent. In the abdominal fat, the bioconcentration factor was negatively correlated with the degree of chlorination. Conversely, more chlorinated PCDD/Fs (hexa- or hepta-congeners) were associated with higher bioconcentration in the liver and breast tissue. In terms of the efficiency of PCDD/Fs elimination, the liver was found to be the fastest, followed by the breast and the abdominal fat. The clearance rate positively correlated with the degree of chlorination, as determined by comparing the apparent elimination rate constant (k) of PCDD/Fs in various tissues. Overall, lower k values observed in this study imply that mule ducks have a reduced clearance of PCDD/Fs in comparison with layer and broiler chickens.

Soil as a source of dioxin contamination in eggs from free-range hens on a Polish farm

The transfer of dioxins from contaminated soil into the food chain has recently become an up-and-coming topic in the environmental policy and health-related consumer protection. Within the framework of the 2011 National Food Survey that monitored the levels of PCDD/Fs and PCBs in foods of animal origin, the sum of the WHO-PCDD/F/PCB-TEQ concentrations exceeding two-fold the European Union's maximum level was detected in eggs from a free-range farm (12.55 ± 2.37 pg WHOPCDD/F/PCB-TEQ/g fat). Investigations have revealed that the source of egg contamination was the backyard soil on which the hens were foraging. A follow-up study of laying hens from this farm has demonstrated the transfer of dioxins into all tested tissues (breast and leg muscles, abdominal fat), liver and ovarian follicles. The bioaccumulation of dioxins was found to be congener and tissue-dependent. The highest concentration was found in the liver, followed by the ovarian follicles, and the adipose tissue. The PCDD/F levels in the liver often were approximately two times higher from those in other materials from the same hen. The potential dioxin intakes with eggs were expressed as the percent of the Tolerable Weekly Intake (TWI), and the Provisional Tolerable Monthly Intake (PTMI). The weekly intake of dioxins would be 3.5 pg WHO-TEQ/kg b.w. (24.9% TWI) for an adult and 20.3 pg WHO-TEQ/kg b.w. (145.2% TWI) for a 3-year old child. Considering a monthly consumption of such contaminated eggs, intake of dioxins would be slightly lower, but still over 100% of the PTMI for a child. The obtained results complement the knowledge on possible dioxin sources in food and are important for risk management authorities.

Suppressive effect of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls transfer from feed to eggs of laying hens by activated carbon as feed additive

In this study, we investigated the suppressive effect of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) transfer from the feed to the eggs of laying hens by using activated carbon as a feed additive. Four groups of six hens (White Leghorn egg-layers; age, 11weeks) were housed as two control groups and two exposure groups for a period of 20weeks. Two control groups were fed with either the basal feed "Control" or basal feed additing activated carbon "Control+C". Another two exposure groups were fed with feed contaminated (about 6ng TEQ kg(-1) feed) by standard solutions of PCDDs/PCDFs and DL-PCBs "Exposure" alone and contaminated feed adding activated carbon "Exposure+C". There was no significant effect on each groups for the growth rate, biochemical blood components, and egg production: these were around the standard levels for poultry in general. Moreover the results in this study showed the availability of activated carbon as a feed additive owing to the reduction in the risk of food pollution by PCDDs/PCDFs and DL-PCBs. The concentration in the eggs of the Exposure group gradually increased following the start of egg-laying but reached a steady state after about 1month. In contrast, the concentration for the Exposure+C group was stationary and below the maximum EU level (6pgTEQg(-1)fat). In comparison to the Exposure group, the Exposure+C group showed a significant decline in the percentage of bioaccumulation into the egg. This reduction due to activated carbon was also observed in the muscle and abdominal fat. The reductions were compound- and congener-dependent for DL-PCBs as follows: PCDDs/PCDFs, non-ortho-PCBs, and mono-ortho-PCBs were more than 90%, 80%, and 50%, respectively, irrespective of the type of tissues. Fat soluble vitamin concentrations in the eggs of the Exposure+C group showed lower trends than the Exposure group. The γ-tocopherol and α-tocopherol concentrations in eggs of Exposure+C group showed a significant reduction of about 40%. However, the addition of activated carbon into animal feed could obviate the remote potential for accidents causing unintentional food pollution with PCDDs/PCDFs and DL-PCBs.

Use of volatile compound metabolic signatures in poultry liver to back-trace dietary exposure to rapidly metabolized xenobiotics

The study investigated the feasibility of using volatile compound signatures of liver tissues in poultry to detect previous dietary exposure to different types of xenobiotic. Six groups of broiler chickens were fed a similar diet either noncontaminated or contaminated with polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs; 3.14 pg WHO-TEQ/g feed, 12% moisture), polychlorinated biphenyls (PCBs; 0.08 pg WHO-TEQ/g feed, 12% moisture), polybrominated diphenyl ethers (PBDEs; 1.63 ng/g feed, 12% moisture), polycyclic aromatic hydrocarbons (PAHs; 0.72 μg/g fresh matter), or coccidiostats (0.5 mg/g feed, fresh matter). Each chicken liver was analyzed by solid-phase microextraction - mass spectrometry (SPME-MS) for volatile compound metabolic signature and by gas chromatography - high resolution mass spectrometry (GC-HRMS), gas chromatography - tandem mass spectrometry (GC-MS/MS), and liquid chromatography - tandem mass spectrometry (LC-MS/MS) to quantify xenobiotic residues. Volatile compound signature evidenced a liver metabolic response to PAH although these rapidly metabolized xenobiotics are undetectable in this organ by the reference methods. Similarly, the volatile compound metabolic signature enabled to differentiate the noncontaminated chickens from those contaminated with PBDEs or coccidiostats. In contrast, no clear signature was pointed out for slowly metabolized compounds such as PCDD/Fs and PCBs although their residues were found in liver at 50.93 (±6.71) and 0.67 (±0.1) pg WHO-TEQ/g fat, respectively.

Pentachlorophenol, polychlorodibenzodioxin and polychlorodibenzofuran in eggs from hens exposed to contaminated wood shavings

Laying hens may be exposed to pentachlorophenol (PCP) present in bedding materials derived from treated timber. As a result, this chemical and its contaminants or degradation products, such as polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs), may be present in eggs. The litter-to-eggs transfer and depletion of these compounds were studied in a flock of laying hens reared on contaminated wood shavings. PCP determination was carried out via high resolution gas chromatography coupled to low resolution mass spectrometry/mass spectrometry (HRGC-LRMS/MS); PCDDs and PCDFs were quantified by HRGC-HRMS (SIM). After substitution of the litter contaminated with PCDDs and PCDFs at an average of 50 pg WHO-TE g(-1) and with PCP at 15 microg g(-1), pooled eggs from six selected hens were sampled twice a month for the depletion study. At steady state, PCDDs and PCDFs showed a transfer ratio of 0.9; for PCP it was 0.03. PCP concentration in eggs (500 ng g(-1) whole weight) fell sharply the second week after exposure withdrawal; for PCDDs and PCDFs (47 pg WHO-TE g(-1) fat, at day 0), the overall TEQ half-life was estimated at an average of 3.8 weeks. Due to differences in toxicokinetics (a faster depletion), PCP does not appear to be a suitable marker of PCDD and PCDF violative levels. However, the prominent analytical contribution of H(7)CCD and O(8)CCD in the contamination profile may help to trace the source of contamination. Among congeners, 2,3,7,8 T(4)CDF exhibited a different depletion pattern, indicating a possible mechanism of active transport.

Polychlorinated biphenyl and low polybrominated diphenyl ether transfer to milk in lactating goats chronically exposed to contaminated soil

This study investigated milk excretion kinetics of PCBs, tetra-BDE (BDE 47), and penta-BDE (BDE 99) in goats exposed to contaminated soil under controlled conditions. The animals were fed (80 days) with feed containing 5% of contaminated soil. During this exposure period, milk was analyzed weekly. At the end of the experiment the PCBs and PBDEs retained in hepatic and adipose tissues were also determined. The soil-milk carry over rates (CORs) of PCBs ranged from 6 to 62%. This result suggests that a large part of ingested soil-bound PCBs was recovered in milk. Significantly different levels between the congeners were reported in the tissues (fat, liver). BDE 47 and 99 excretions in milk achieved a plateau after 2 weeks of exposure, and their corresponding CORs were about 30%. These two congeners showed a significantly (P < 0.05) lower accumulation in the adipose tissue than the major PCB congeners. The concentrations of BDE 47 and 99 in the liver were the same as PCB concentrations. This result suggests that the low brominated congeners are submitted to the metabolism more extensively than the major PCBs.

PCDD/F and DL-PCB levels in meat from broilers and rabbits fed with fish-oil enriched feeds

The aim of this study was to assess the effect on the final levels of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in meat when fats, in particular fish oils, are included as ingredients in feeds. Two types of animals (broilers and rabbits) were fed with three different experimental feeds containing varying amounts of two selected fish oils. PCDD/Fs and DL-PCBs were determined in the fish oils, the feeds and in the animals' meat. For broilers, PCDD/F and DL-PCB profiles in meat samples were similar to those found in the corresponding feeds, even though bioaccumulation of the highest chlorinated PCDD/F congeners seemed to decrease. Depending on the treatment, PCDD/F and the sum of PCDD/F and DL-PCB levels were 1.11-4.60 and 6.03-16.71 pg WHO-TEQ/g fat, respectively. For most of the cases, these values exceeded the maximum established by the Commission Regulation (EC) No. 1881/2006. In contrast, the levels of these contaminants in the corresponding feeds ranged from 0.11 to 0.54 pg WHO-TEQ/g, in the case of PCDD/Fs, and from 0.59 to 1.75 pg WHO-TEQ/g, when DL-PCBs were also included. These levels were, in general, below the maximum allowed by the Commission Directive 2006/13/EC. The results of the experiments with rabbits were not as conclusive as those for broilers although bioaccumulation appeared to be slower.

PCDD/Fs and dioxin-like PCBs in home-produced eggs from Belgium: levels, contamination sources and health risks

This paper discusses the dioxin TEQ levels as determined by the chemically activated luciferase gene expression assay (CALUX) and by HRGC-HRMS in eggs, soils, faeces and kitchen waste samples obtained in the CONTEGG study. The samples were collected in each Belgian province at private homes and in small gardens where chickens are held. The CALUX levels for eggs sampled in autumn were higher than the levels in eggs obtained at the same locations in spring (median values of 5.86 and 4.08 pg CALUX TEQ/g fat, respectively). The total WHO-TEQ levels in eggs, determined by HRGC-HRMS, ranged from 3.29 to 95.35 pg TEQ/g fat in autumn and from 1.50 to 64.79 pg TEQ/g fat in spring. In the soils on which the chickens forage, levels of 2.51-11.35 pg I-TEQ/g in autumn and 2.00-7.86 pg I-TEQ/g in spring were found. The congener pattern of PCDD/Fs in the eggs, soils and faeces was dominated by OCDD, in addition to 1,2,3,4,6,7,8-HeptaCDD, OCDF and 1,2,3,4,6,7,8-HeptaCDF. The predominant dioxin-like PCBs were PCB118, PCB 105 and PCB 156. The dioxin-like PCBs contributed on average 47%, 14% and 20% to the total WHO-TEQ in eggs, soils and faeces, respectively. Kitchen waste samples were very low-contaminated with dioxin-like compounds. The present results showed a good agreement between egg and soil TEQ levels for PCDD/Fs but not for dioxin-like PCBs. This study showed that current soil levels found in some private gardens do not lead to egg levels below the current EU maximal level of 6 pg total TEQ/g fat for dioxins and dioxin-like PCBs. The consumers of the analysed eggs attained 5-79% of the tolerable weekly intake (TWI) of 14 pg TEQ/kg bw for dioxins and dioxin-like PCBs by exposure to their home-produced eggs only.

Brominated flame retardants in Belgian home-produced eggs: levels and contamination sources

The extent and the sources of contamination with brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), in home-produced eggs from free-foraging chicken of Belgian private owners were investigated. Various factors, such as seasonal variability, exposure of chickens through diet (kitchen waste) and soil, and elimination of BFRs through eggs and faeces were assessed. PBDEs were more important than HBCD in terms of concentrations and detection frequency. Concentrations of PBDEs and HBCD in Belgian home-produced eggs were relatively low and comparable with reported levels from other European countries and the US. The concentrations of PBDEs (sum of 13 congeners, including BDE 209) ranged between not detected and 32 ng/g lipid weight (lw), with medians of 3.0 and <2.0 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively. When present, BDE 209 was the major PBDE congener (45% of sum PBDEs). When BDE 209 was not detected, the PBDE profile was composed of PentaBDE (BDE 99 and BDE 47), with, in some cases, higher contribution of OctaBDE (BDE 183 and BDE 153). HBCD was also detected (<0.4 and 2.9 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively), but at lower detection frequency. The highest HBCD value was 62 ng/g lw. The similarity between profiles and seasonal variations in the concentrations of BFRs in soil and eggs indicate that soil is an important source, but not the sole source, for eggs laid by free-foraging chicken. The contamination of eggs with PBDEs and HBCD appears to be of low concern for public health and the contribution of eggs to the total daily intake of PBDEs appears to be limited (10% for chicken owners and 5% for the average Belgian consumer).

Transfer of soil contaminants to home-produced eggs and preventive measures to reduce contamination

Uptake studies have shown that chickens foraging on soils contaminated with environmental pollutants accumulate these compounds into their eggs. Home-produced eggs thereby show higher contamination levels than commercially produced eggs. It was the aim of this study to identify the major source of two environmental pollutants in home-produced eggs, i.e. dioxins and lead, to formulate preventive measures to reduce the contamination levels of such eggs, and to assess the feasibility of the formulated measures in terms of the perception and behavior of private egg producers towards such measures. The major source of dioxins and lead in eggs, i.e. the soil, was identified by transfer calculations of the pollutants from the feed and soil towards eggs. Preventive measures to reduce soil intake or geophagy and hence egg contamination levels, were formulated and their feasibility evaluated through interviews with private chicken owners. The results show that a paved surface inside the henhouse, an indoor feeding place and providing a sufficient surface area per chicken were considered the most appropriate in terms of feasibility and willingness to apply the measures by the private chicken owners. To enhance the effect of the measures, a combination of measures supported and promoted at policy level is considered as a good strategy to reduce contamination levels in home-produced eggs.

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans in laying ducks

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in laying ducks was determined at different degree of feed contamination. To observe the extent of the transfer of 17 PCDD/Fs from feed to the duck eggs and duck meat, 18 ducks were divided into 3 groups (6 in each group) and fed feed with two different levels of PCDD/Fs. As a control, one group of ducks was fed with the non-contaminated feed for comparison, while the other 2 groups were exposed to the feed doped with EAF dusts (fly ash). The experiment lasted for 60 days, with an exposure duration of 41 days and the subsequent non-contaminated feed being given for an additional 19 days. PCDD/F levels in the eggs of the all 3 groups were observed to increase significantly on the 15th day. For the low contaminated group, PCDD/F levels reached 2.61 pg WHO-TEQ/g lipid at day 41, whereas those of the high contaminated group accounted exceeded 3 pg/g lipid on the 15th day. Furthermore, PCDD/Fs levels in the duck meat were analyzed before and after exposure duration, and at the end of the experiment. The results showed that the level of PCDD/F in the duck eggs and the duck meat may reach unacceptable levels due to the effect of accumulation, although the PCDD/Fs in the duck feed were at acceptable levels.

Occurrence and bioaccumulation study of PCDD and PCDF from mineral feed additives

Extraction of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) was evaluated in sepiolite matrices. Soxhlet extraction using different extracting strategies and acid treatment were tested. Acid treatment or Soxhlet extraction using a mixture of toluene:ethanol as solvent allowed to reach the minimum requirements for recovery rates. However, Soxhlet extraction using a mixture cyclohexane:toluene as extracting solvent did not allow to comply with these minimum requirements. Significant differences were obtained in TEQ units when acid treatment was applied in comparison to Soxhlet extraction. This fact can be explained because the use of drastic acid conditions allows removing strongly adsorbed analytes which can be uniquely extracted after a total destruction of the crystalline. On the contrary, Soxhlet extraction was not able to destroy the structure of sepiolite and as a consequence the PCDDs/Fs remain adsorbed in the internal structure of the mineral. A bioaccumulation study was also conducted to evaluate the transference of PCDDs/Fs from the sepiolite into the animal when fed with feed containing sepiolite. Four groups of chickens were exposed through diet to a control feed, feed with 3% w/w sepiolite, spiked feed contaminated with PCDDs/Fs and feed containing contaminated kaolinitic clay. Livers of animals were analyzed throughout the exposure period. Results of this trial showed that the performance of broilers was not affected by the presence of dioxins at levels tested, and chickens did not show any abnormal behaviour. Dioxins intentionally added to the diet were significantly absorbed and accumulated in liver, whereas the PCDDs/Fs from sepiolite were not available for chickens since livers from broilers fed 3% sepiolite presented similar WHO-TEQ values than those from broilers fed control diet.

Comparison of levels of polychlorinated biphenyls in edible oils and oil-based products--possible link to environmental factors

Food consumption has been widely reported to be the main source of human exposure to PCBs. A total of 47 samples of food products on sale in supermarkets in the United Kingdom were thus analyzed for PCBs to determine residual levels in oil and oil-based products. The objective was to compare the measured levels of total PCBs (Sigma PCBs) in food products to those reported in various environmental compartments. Combined extraction and online clean up was achieved using Accelerated Solvent Extraction (ASE) to recover target analytes for analysis by GC-MSD (gas chromatography mass spectrometry). Sigma PCBs (ng/g) in each product were in the ranges of 4.73-44.38 edible oil; 1.40-6.18 mayonnaise; 1.21-6.25 salad cream; 1.28-5.64 seafood sauce, and 0.97-15.08 exotic dressing. The level of human exposure to PCBs in all products was < 1 microg/kg body weight/day when considering a 70 kg male or 57 kg female, possibly reflecting the reported decline of PCBs in the environment.

PCDD/Fs and DL-PCBs in feeding fats obtained as co-products or by-products derived from the food chain

Among the tasks included in the "Quality and safety of feeding fats obtained from co-products or by-products of the food chain" Project, supported by the European Union and included in the 6th Framework Program, a number of fats and oils collected as co- or by-products from the food chain were selected for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and 'dioxin-like' polychlorinated biphenyls (DL-PCBs). In the majority of the cases these samples are currently employed as feed ingredients. Nevertheless, additional fats, which are forbidden for feedstuff purposes were also considered in this study. In general terms, fats and oils were classified taking into account their nature and the processes applied to obtain these co- or by-products. PCDD/F and DL-PCB levels were evaluated in a first group of samples composed of fish oils, animal fats and lecithins. As expected, fats and oils with an animal origin presented higher concentrations, expressed in pg WHO-TEQ/g, compared to the levels found in vegetable samples like lecithins. The category of fish oils had the highest values for both PCDD/Fs and the sum of PCDD/Fs and DL-PCBs, with some samples showing levels above the maximum established at the present legislation related to the presence of PCDD/Fs and DL-PCBs in animal feed [Commission Directive 2006/13/EC of 3 February 2006 amending Annexes I and II to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed as regards dioxins and dioxin-like PCBs. Official Journal of the European Communities L32, 44-53]. In a second group, fats and oils with a more complex composition obtained from different transformation processes or even mixtures of fats were considered; thus, acid oils from chemical refining, acid oils from physical refining, recycled cooking oils, oils extracted from exhausted bleaching earths, hydrogenated by-products, fatty acids calcium soaps and miscellaneous fats were analyzed. The data revealed a significant variability in PCDD/F and DL-PCB levels, expressed in pg WHO-TEQ/g, in these products. It has to be pointed out that the analyses of fats and oils belonging to these categories of products were sometimes difficult due to the complexity of the samples. In terms of legislation most of these samples cannot be easily included into one of the specific categories of substances intended for feedstuff purposes that are regulated in Commission Directive 2006/13/EC.

Flame retardants (PBDEs) in marine turtles, dugongs and seafood from Queensland, Australia

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in numerous products. These compounds have been found to enter the marine environment where they have the potential to bioaccumulate in biota. Limited information is currently available concerning the levels of PBDEs in Australian marine wildlife. This study presents baseline information on PBDE levels in a variety of marine species from Queensland, Australia and considers the influence of species-specific factors on contaminant levels and tissue distribution in marine turtles. Overall, the PBDE levels measured in this study are relatively low compared to marine biota from the northern hemisphere, indicating low level input into the marine system of Queensland. This is in general agreement with global estimates which suggest low PBDE usage in Australia. Previous studies, however, have found relatively high PBDE levels in Australian human milk and sera. This discrepancy in contamination trends between terrestrial and marine biota suggests that future transport of PBDEs may occur to the marine system in Australia.

Absorption, disposition and excretion of polybrominated diphenyl ethers (PBDEs) in chicken

Except for fish, no toxicokinetic data on polybrominated diphenyl ethers (PBDEs) is available on relevant animals for the human food chain. In the present work, absorption, elimination through eggs and disposition of PBDEs in laying chickens were studied and compared to dioxin behaviour. Hens were fed with diet containing 3.4 mg/kg feed of PBDEs and 0.95 ng TEQ/kg feed of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs). PBDEs have been demonstrated to show drastically different behaviours from PCDD/Fs and dioxin-like compounds. Excretion of PBDEs increased for two weeks and then decreased to nearly 0%. Sixty-two percent of ingested 2,2',4,4'-tetraBDE (BDE-47) were found in excreta after two weeks, suggesting a reductive debromination of PBDEs in the digestive tract. PBDE level in eggs increased during five weeks and reached 24 microg/g fat. After then, levels decreased to 3 microg/g fat at the end of the trial. PBDE bioconcentration factors estimated for abdominal fat varied from 0.7 for BDE-47 to 2 for BDE-183.

Dioxins and related compounds in albatrosses from the Torishima Island, Japan: accumulation features by growth stage and toxicological implications

Concentrations of dioxins and related compounds (DRCs), such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs), were determined in eggs, nestlings, and adults of black-footed albatross (BfA; Diomedea nigripes) and short-tailed albatross (StA; Diomedea albatrus) collected from the Torishima Island in Japan during 2002, which is one of their breeding grounds. Observed DRC concentrations, especially PCDFs and non-ortho Co-PCBs, in eggs of BfA and StA were relatively higher than those in other oceanic, coastal, and inland wild birds reported recently and were comparable to those in a pooled BfA egg from Midway Atoll in 1993, implying continuous input of these contaminants into open ocean and possible albatross-specific exposure. Concentrations of PCDDs except 12378-P5CDD and high-chlorinated PCDFs in 3-month-old BfA nestling were lowerthan those in 1-month-old nestling, indicating their developmental dilution. On the other hand, higher levels of T4-H6CDFs and Co-PCBs, especially low-chlorinated congeners such as 2378-T4CDF and T4CB77, were found in 3-month-old BfA nestling, suggesting specific exposure to these contaminants, possibly due to their higher transportability than high-chlorinated congeners. Estimated biomagnification factors of almost all the congeners in adults were apparently greater than those in nestlings, except 2378-T4CDF, T4CB77, and H7-O8-CDD/Fs. This could be due to preferential metabolism of 2378-T4CDF and T4CB77 and lower uptake efficiency of high-chlorinated congeners through the gastrointestinal tract in adults. Toxic equivalents in BfA and StA eggs estimated using WHO-avian toxic equivalency factors exceeded some toxicity thresholds for avian embryos, indicating possible adverse effects of DRCs to albatross embryos.

Residues of dioxins (PCDD/Fs) and PCBs in eggs, fat and livers of laying hens following consumption of contaminated feed

Laying hens were fed with feed from the Belgian dioxin incident diluted ten-fold with non-contaminated feed, resulting in concentrations of 61 ngTEQkg(-1) PCDD/Fs, 23 ngTEQkg(-1) non-ortho PCBs, 116 ngTEQkg(-1) mono-ortho PCBs and 3.2 mgkg(-1) of the seven indicator PCBs. Following exposure for seven days, feed was replaced by non-contaminated feed for a period up to six weeks. Concentrations of PCDD/Fs in eggs showed a maximum of 214 pgTEQg(-1) fat after nine days and decreased to 44 pgTEQg(-1) after seven weeks. Dioxin concentrations in abdominal fat of chickens killed just after the last treatment, or after 1, 3 or 6 weeks on clean feed were 69, 84, 54 and 41 pgTEQg(-1) fat, respectively. Concentrations in livers decreased more rapidly, being 35, 7, 4 and 3 pgTEQg(-1) tissue, respectively. In both eggs and tissues, total TEQ concentrations were 3-4 times higher. Concentrations of the seven indicator PCBs in egg fat showed a stronger decrease with concentrations of 16.5 microgg(-1) at the peak (day 9) and 2.2 microgg(-1) after seven weeks. Corresponding concentrations in abdominal fat were, respectively, 4.6 and 2.6 microgg(-1) fat, and in livers 0.77 and 0.14 microgg(-1) tissue. The ratio of indicator PCBs to PCDD/Fs in feed was 52200. In eggs this ratio was initially higher (85000), but decreased towards 50000 after six weeks on clean feed. In abdominal fat the ratio varied between 49000 and 67000. In livers, the ratio was initially low (22000) but increased to 45000 towards the end of the study. It is concluded that the behaviour of PCDD/Fs and PCBs in laying hens is comparable and that the use of indicator PCBs appears to be a good alternative for PCDD/Fs but only in the case of co-exposure to both PCBs and PCDD/Fs, such as in incidents with PCB oil.

Effects of two infectious bursal disease vaccine virus strains on hepatic microsomal enzyme activities in chickens

The influence of two infectious bursal disease vaccines on the activities of hepatic microsomal enzymes aniline hydroxylase, ethylmorphine N-demethylase, NADPH-cytochrome c reductase, aryl sulphotransferase and p-nitrophenol UDP-glucuronyltransferase was investigated in chickens. The vaccines contained attenuated Winterfield 2512 and VMG-91 strains, respectively. The activities of enzymes were determined on postvaccination days 0, 2, 5 and 7. At the same time, post-mitochondrial supernatant, cytosolic and microsomal pellet protein concentrations were determined. As expected, the antibody titres against infectious bursal disease virus in the serum were increased in both tested groups in relation to each administered vaccine. Using RT-PCR, the presence of the VP2 gene fragment of virus in the liver of chicken was demonstrated 4 and 6 h after vaccination. The results of this study suggest that the two commercial vaccines modulate the activities of five enzymes tested, and that the two attenuated vaccines applied triggered induction and/or inhibition of phases I and II of biotransformation enzyme activities.

Toxicokinetic study of dioxins and furans in laying chickens

Since foodstuffs from animal origin and particularly poultry products have been pointed out several times as reservoir of dioxins and related compounds, notably in Belgium few years ago, food chain safety issues appeared. Although food chain contamination incidents occurred many times through contaminated feedstuffs consumption in commercial chicken farms, very few studies have been carried out on transfer of dioxins and related compounds from commercial feed to hens. The present work continues a preliminary study on dioxin transfer in laying chickens carried out in our lab and available on-line on November 2004 in Environment International. In this work, absorption of dioxins were not preferential for 2,3,7,8-substituted congeners, increase with increasing number of chlorines, and was not linearly dependent of the octanol/water partition. Only 2,3,7,8-congeners were found in all organs studied, and these latter showed the same congener profile and similar lipid-normalized concentration, except for the liver. Abdominal fat and liver seemed to be the major storage sites and the liver preferentially retained highly chlorinated congeners. Unfortunately in this previous trial, laying process stopped very early for unknown reason leading to a considerable lost of information. In the present toxicokinetic study, more complete gastrointestinal absorption, excretion in eggs and bioaccumulation of dioxins in different tissues were investigated in chickens fed for 14 weeks with a 9 ng TEQ/kg contaminated feed. Stable levels were reached after 7 weeks in excreta and 9 weeks in eggs. During the whole trial, gastrointestinal absorption ranged between 41% and 91% depending on the congener. At steady state conditions, excretion of 1,2,3,4,6,7,8-HpCDD, OCDD, 1,2,3,4,6,7,8-HpCDF and OCDF exceeded 100% demonstrating excretion from tissues of these congeners which were also the most abundant in feed. 1,2,3,7,8-PeCDD, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF, 1,2,3,7,8,9-HxCDF and 2,3,4,6,7,8-HxCDF seemed to be metabolized more efficiently. Lipid adjusted concentrations and pattern were unexpectedly similar in the abdominal fat and the liver. On the contrary, eggs and breast muscles showed different pattern with higher level for high chlorinated congeners. When extrapolating our results, we found that a feed containing 0.750 ng TEQ/kg of dioxins (European norm for feedstuff) would cause a level lower than the maximum threshold level of 3 pg TEQ/g fat for chicken eggs fixed by European Communities. Nevertheless, a concentration lower than 0.6 ng TEQ/kg in feed would be needed to produce breast muscles less contaminated than 2 pg TEQ/g fat authorized in European.