Polychlorinated Dibenzo-p-dioxins/furans Research Articles

Systematic surveillance for management of Dioxin contamination risks in the food chain: Germany and related cases

Environmental pollutants, such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and dioxin like PCBs keep appearing in the food chains due to their recalcitrant environmental characteristics and due to practices of raw materials, feed and food producers. Despite emission control measures taken, which have resulted in significant reductions in environmental contamination, Dioxin-food crises have appeared and still appear in the media almost every year, or sometimes several times a year since the beginning of the 21st century. In the late years of the last century, the Belgian chicken crisis, lasted for more than half a year regarding import/export bans among EU countries and with non-European countries. The total economic costs of this crisis exceeded billion Euro. Since then the European Commission has established a set of instruments, including a rapid alert system, tight control measures and maximum limit values in food , feed and raw materials within the EU and for imported goods and products imported from non-EU countries. The development, introduction, and EU acceptance of fast and high capacity screening bioassays, such as CALUX provide for a methodology that can quickly assess the extent of the contamination, and therefore can limit the spreading of the problem and allow the early market release of food, feed and related products once they have been cleared by the fast screening tool. Nevertheless, the introduction of fast bio-analytical tools by various EU member countries and in the World is slow, mostly due to a variety of barriers (acceptance, psychological, competition) well-known to exist for introduction of novel technologies. However, in food crisis situations, affected countries show a high willingness to quick adoption and implementation of fast screening methods, in order to provide for sufficient analytical capacity and to limit the economic damages due to e.g., prolonged export bans. In this presentation the use and application of CALUX as a fast screening method is given, as well as its application in several food crisis cases will be presented, including the recent German Dioxin crisis in 2011.

Use of quantitative-structure property relationship (QSPR) and artificial neural network (ANN) based approaches for estimating the octanol-water partition coefficients of the 209 chlorinated trans-azobenzene congeners

Polychlorinated azobenzenes (PCABs) can be found as contaminant by products in 3,4-dichloroaniline and its derivatives and in the herbicides Diuron, Linuron, Methazole, Neburon, Propanil and SWEP. Trans congeners of PCABs are physically and chemically more stable and so are environmentally relevant, when compared to unstable cis congeners. In this study, to fulfill gaps on environmentally relevant partitioning properties of PCABs, the values of n-octanol/water partition coefficients (log KOW) have been determined for 209 congeners of chloro-trans-azobenzene (Ct-AB) by means of quantitative structure-property relationship (QSPR) approach and artificial neural networks (ANN) predictive ability. The QSPR methods used based on geometry optimalization and quantum-chemical structural descriptors, which were computed on the level of density functional theory (DFT) using B3LYP functional and 6–311++G** basis set in Gaussian 03 and of the semi-empirical quantum chemistry method (PM6) of the molecular orbital package (MOPAC). Polychlorinated dibenzo-p-dioxins (PCDDs), -furans (PCDFs) and -biphenyls (PCBs), to which PCABs are related, were reference compounds in this study. An experimentally obtained data on physical and chemical properties of PCDD/Fs and PCBs were reference data for ANN predictions of log KOW values of Ct-ABs in this study. Both calculation methods gave similar results in term of absolute log KOW values, while the models generated by PM6 are considered highly efficient in time spent, when compared to these by DFT. The estimated log KOW values of 209 Ct-ABs varied between 5.22–5.57 and 5.45–5.60 for Mono-, 5.56–6.00 and 5.59–6.07 for Di-, 5.89–6.56 and 5.91–6.46 for Tri-, 6.10–7.05 and 6.13–6.80 for Tetra-, 6.43–7.39 and 6.48–7.14 for Penta-, 6.61–7.78 and 6.98–7.42 for Hexa-, 7.41–7.94 and 7.34–7.86 for Hepta-, 7.99–8.17 and 7.72–8.20 for Octa-, 8.35–8.42 and 8.10–8.62 for NonaCt-ABs, and 8.52–8.60 and 8.81–8.83 for DecaCt-AB. These log KOW values shows that Ct-ABs are compounds of relatively low environmental mobility (log KOW > 4.5) and of significant bioaccumulation potential.

Analysis of human milk to assess exposure to PAHs, PCBs and organochlorine pesticides in the vicinity Mediterranean city Mersin, Turkey

Assessment of human exposure to environmental persistent organic pollutants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) based on the levels in human breast milk provides a reasonable tool not only to assess the contaminant burden in mothers but also to assess potential exposure of breast-fed neonates. There are limited data on levels of PCBs and OCPs in humans but no previous reports from Turkey on chemically determined levels PAHs in human milk. The aim of this study was to report the levels and accumulation profiles of OCPs, PCBs and PAHs in 47 breast milk samples obtained from a Mediterranean city, Mersin. High resolution analyses were performed by a gas chromatography coupled with mass spectrometer (GC–MS). Dichlorodiphenyldichloroethane (4.4′-DDE) was the dominant pollutant. Beta-hexachlorocyclohexane (ß-HCH), dichlorodiphenyltrichloroethane (4.4′-DDT), dieldrin, hexachlorobenzene, oxy-chlordane, cis-heptachlorepoxide were the other main OCPs detected. Mean levels of ΣPCB congeners and WHOPCB-TEQ were 9.94 and 0.001ng/g lipid, respectively. PCB 153 showed the highest concentration (3.37ng/g lipid), followed by PCB 138 and 180. For the dioxin-like PCBs, PCB 118 was the dominant (0.97ng/g lipid). Naphthalene, phenanthrene, pyrene and fluoranthene were the major PAHs among the 16 PAHs detected. The estimated daily intakes of DDTs, PCBs, HCHs and HCB were not exceeded the tolerable daily intake (TDI) proposed by the Health Canada Guideline. These results indicate that the neonates of Mersin city are exposed to persistent organic pollutants analyzed in this study. However, neonates born in Mersin province are less exposed than the ones born in other regions, considering OCP and PCB levels in breast milk.

In VitroTransactivation Potencies of Black-Footed Albatross (Phoebastria nigripes) AHR1 and AHR2 by Dioxins To Predict CYP1A Expression in the Wild Population

Our previous studies have detected high levels of dioxins and related compounds (DRCs) including polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and coplanar PCBs (Co-PCBs) in the black-footed albatross (BFA), Phoebastria nigripes, from the North Pacific region. We have also cloned two aryl hydrocarbon receptors, AHR1 and AHR2, of the BFA. To evaluate the sensitivity to DRCs in the BFA and to assess the status of cytochrome P450 1A (CYP1A) induction in the wild population, this study investigated the mRNA expression levels of BFA AHR1 and AHR2 and also the transactivation potencies of each AHR by 15 selected DRC congeners. Quantitative real-time PCR of BFA AHR mRNAs showed that hepatic AHR1 is more highly expressed than AHR2. Transactivation by graded concentrations of individual DRCs was measured in COS-7 cells, where BFA AHR1 or AHR2 was transiently transfected. For congeners that exhibited AHR-mediated dose-dependent activities, 50% effective concentration (EC(50)) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) relative potencies (REPs) were estimated. Based on the estimates of the REPs, TCDD induction equivalency factors (IEFs) were determined. For BFA AHR1, PeCDF was equipotent to TCDD, but other congeners exhibited lower IEFs. For BFA AHR2, PCDD/F congeners except OCDD/F showed IEFs ≥ 1.0. Using BFA AHR1- or AHR2-IEFs and hepatic concentrations of DRCs in North Pacific BFAs, TCDD induction equivalents (IEQs) were calculated. We further constructed nonlinear regression models on the relationships between BFA AHR1- or AHR2-IEF derived total IEQ or WHO-TEF derived total TEQ and ethoxyresorufin-O-deethylase activity (EROD) in the liver of wild BFAs. The results indicated that the relationships of BFA AHR1- and AHR2-based IEQs and EROD were predictable from BFA AHR1- and AHR2-mediated transactivation by TCDD, respectively. Collectively, these results suggest that the in vitro assay incorporating the AHR of species of concern would be a useful tool to predict the sensitivity to DRCs in the species and CYP1A induction in the wild population.

Levels of PCDD/Fs and DL-PCBs in selected foods and estimated dietary intake for the local residents of Luqiao and Yuhang in Zhejiang, China

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were measured by high resolution gas chromatograph/high resolution mass spectrometer (HRGC/HRMS) in six food groups from Luqiao (LQ) where the e-waste has been recycled and from Yuhang (YH) where the agriculture dominates in Zhejiang Province in China. The total WHO-TEQ values of PCDD/Fs and DL-PCBs in selected foods from LQ were significantly much higher than those from YH. The highest level of the total WHO-TEQ was in crucian carp (10.87pgg−1w.w.) followed by duck (3.77pgg−1w.w.), hen eggs (2.80pgg−1w.w.), chicken (2.43pgg−1w.w.), rice (0.08pgg−1w.w.) and vegetables (0.022pgg−1w.w.) in LQ. By contrast, the highest levels were measured in duck (0.74pgg−1w.w.) followed by hen eggs (0.69pgg−1w.w.), crucian carp (0.55pgg−1w.w.), chicken (0.44pgg−1w.w.), vegetables (0.002pgg−1w.w.) and rice (0.0002pgg−1w.w.) in YH, respectively. The monthly intake of PCDD/Fs and DL-PCBs for the local residents was 401.75pgWHO-TEQg−1w.w. in LQ, which is above the provisional tolerable monthly intake (PTMI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). We determined a monthly intake of 37.13pgWHO-TEQg−1w.w. in YH, which is below the PTMI. Crucian carp was the predominant contributor to the estimated monthly intake (EMI), accounting for 67.74% and 36.51% in LQ and YH, respectively. High levels of PCDD/Fs and DL-PCBs in selected foods indicate severe contamination of these pollutants in the e-waste recycling site.

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in breast milk from Zhejiang, China

Breast milk samples (n=74) from the general maternal population of Zhejiang province were analyzed for polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Samples were divided into urban and rural groups. Mean ∑PCDD/F, ∑PCB and ∑PBDE concentrations were 71.4±40.8, 42774±27841 and 2679±944pgg−1 lipid in the urban group and 38.6±38.1, 26546±11375 and 2731±1093pgg−1 lipid in the rural group, respectively. WHO-TEQ concentrations for dioxin-like PCBs and PCDD/Fs were 2.66±1.43 and 3.90±2.60pgg−1 lipid in the urban group and 1.83±0.93 and 2.27±1.55pgg−1 lipid in the rural group, respectively. Congener profiles for these pollutants were compared between human samples (adipose tissue and breast milk) and foodstuffs (seafood, hen eggs, and freshwater fish). Similar PCB and PCDD/F congener patterns were observed, suggesting that dietary intake is a significant source for human exposure to PCBs and PCDD/Fs. However, much lower PBDE congener levels were detected in breast milk than in foodstuffs, which implies that pathways other than dietary intake may also account for human exposure to PBDEs.

Dioxin Emissions and Human Exposure in China: A Brief History of Policy and Research

Dioxin Emissions and Human Exposure in China: A Brief History of Policy and Research

Fast Cleanup System Combined with a Dioxin-responsive Element-driven Luciferase Bioassay for Analysis of Polychlorinated Dibenzo-p-dioxins/furans in Sediments and Soils

A green technique was designed for assessing toxic equivalence (TEQ) levels of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in sediments and soil from dioxin-contaminated areas. This technique combines a fast cleanup system with a dioxin-responsive-element (DRE)-driven luciferase bioassay. Samples from sediment (n = 10) and soil (n = 11) were analyzed with the technique; levels of PCDD/Fs ranged from 75.1 to 2,670 ng DRE-driven luciferase activity (DL)-TEQ/kg dry weight (d.w.). Significant correlations were found between DL-TEQs (by the bioassay) and PCDD/F WHO-TEQs (by HRGC/HRMS). DL-TEQs is significantly correlated with WHO-TEQs of 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD using a multiple stepwise linear regression model (adjusted R(2) = 0.962, p < 0.001).

Dioxins in Primary Kaolin and Secondary Kaolinitic Clays

Since 1996 dioxins have been repeatedly detected worldwide in Tertiary ball clays used as anticaking agent in the production of animal feed and a variety of other applications. The dioxins of these natural clays are very unlikely of anthropogenic source, but no model of dioxin enrichment has been established. A hypothetical model is presented which explains the highly variable dioxin loadings of the Tertiary kaolinitic clays by natural addition during clay-sedimentation. To prove this hypothesis, Tertiary primary nonsedimentary kaolin and sedimentary kaolinitic clays were collected at three profiles in Europe and analyzed for mineralogy, chemistry, organic carbon, and polychlorinated dibenzo-p-dioxins/-furans (PCDD/F). Primary kaolin, kaolinitic, and lignitic clays contained almost no PCDFs. PCDD concentration differed markedly between primary kaolin (3-91 pg/g) and secondary kaolinitic clay (711-45935 pg/g), respectively, lignitic clays (13513-1191120 pg/g). The dioxin loading of secondary kaolinitic and lignitic clays is approximately 10 to a few thousand times higher than in the primary kaolin or recent environmental settings. The dioxin concentrations decrease from octachlorodibenzo-p-dioxin to the tetrachlorodibenzo-p-dioxins and exhibit the "natural formation pattern". No correlation between PCDD/F concentration and bulk composition of clays was found. These findings support the hypothesis of the enrichment of dioxin in clays during sedimentation.

Reducing persistent organic pollutants while maintaining long chain omega-3 fatty acid in farmed Atlantic salmon using decontaminated fish oils for an entire production cycle

Oily fish are an important source of health promoting nutrients such as the very long chain marine omega-3 (VLC-n3) fatty acids and simultaneously a source of potentially hazardous contaminants. Fish oils that are used in fish feed are the main source for both contaminants and VLC-n3. Decontamination techniques have recently been developed to effectively remove persistent organic contaminants from fish oils. The aim of the present study was to assess the level of potentially hazardous contaminants and the health beneficial fatty acids in Atlantic salmon reared on novel decontaminated feeds. Atlantic salmon were fed for 18 months (an entire seawater production cycle) on diets based on decontaminated or non-treated (control) fish oils until market size (∼5 kg). The level of known notorious persistent organic pollutants (POPs, i.e. dioxins, dioxin-like polychlorinated biphenyls (DL-PCBs), non dioxin-like PCBs, poly brominated diphenyl ethers (PBDE), and organochlorine pesticides), as well as fatty acid composition were analysed in fish oils, the two diets, and Atlantic salmon fillet. The oil decontamination process was a two-step procedure using active carbon and short path distillation. The fillet levels of POPs in market size fish were reduced by 68–85% while the concentration of very long chain omega-3 fatty acids was reduced by 4–7%. No differences in biomarkers of dioxin-like component exposures, such as hepatic gene expression of CYP1A or AhR2B, CYP1A protein expression and 7-ethoxyresorufin O-deethylase (EROD) activity, were observed between salmon raised on normal or decontaminated feeds, thus indicating that the difference in POPs levels were of no biological significance to the fish. Atlantic salmon reared on decontaminated feeds had sum polychlorinated dibenzodioxins/furans (PCDD/Fs) and DL-PCB concentrations that were comparable with terrestrial food products such as beef, while the level of marine omega-3 fatty acids remained as high as for commercially farmed Atlantic salmon.

Reduction of a large fish tissue analyte database: Identifying and assessing data specific to a remediation site for risk assessment application

The Lower Passaic River (LPR) is one of the most heavily industrialized waterways in the US with both historical and continuing discharges of chemicals from point and non-point sources. Significant efforts have been initiated on behalf of public, private, and regulatory entities to restore this degraded urban river. Considerable attention has been devoted to characterizing environmental media with respect to human and ecological risk. As part of these efforts, a wealth of environmental data have been collected and analyzed for a variety of metals, pesticides, organic compounds, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins/furans (PCDD/Fs), and dioxin-like compounds. The objectives of the study described in this paper were two-fold: (1) to generate LPR-specific data for use in human health risk assessment by characterizing concentrations of contaminants in LPR fish tissue samples based on publicly available data using a methodical and transparent approach, and (2) using the resulting data, to calculate the contaminant concentrations in a “Representative Fish,” which is a representation of proportional fish tissue concentrations calculated based upon consumption patterns of LPR anglers. The data reduction, processing, and analyses described provide a representative dataset for the conduct of a human health assessment associated with fish consumption from the LPR.

Estimating sediment quality thresholds to prevent restrictions on fish consumption: Application to polychlorinated biphenyls and dioxins–furans in the Canadian Great Lakes

Sediment quality thresholds (SQTs) are used by a variety of agencies to assess the potential for adverse impact of sediment-associated contaminants on aquatic biota, typically benthic invertebrates. However, sedimentary contaminants can also result in elevated fish contaminant levels, triggering consumption advisories that are protective of humans. As such, SQTs that would result in fish concentrations below consumption advisory levels should also be considered. To illustrate how this can be addressed, we first calculate biota sediment accumulation factors (BSAFs) for polychlorinated biphenyls (total PCB) and polychlorinated dioxins-furans (PCDD/Fs) in the Canadian Great Lakes using measured lake sediment and fish tissue concentrations in 4 fish species, namely, lake trout, whitefish, rainbow trout, and channel catfish. Using these BSAFs and tissue residue values for fish consumption advisories employed by the Ontario Ministry of the Environment (OMOE, Canada), we derive fish consumption advisory-based SQTs (fca-SQTs) that are likely to result in fish tissue residues that are safe to eat without restriction. The PCDD/Fs fca-SQTs ranged from 6 to 128 pg toxic equivalents (TEQ)/g dry weight (dw) and were above the Canadian Council of the Ministers of the Environment (CCME) threshold effect level (TEL) of 0.85 pg TEQ/g dw. In contrast, the total PCB fca-SQTs ranged from 1 to 60 ng/g dw and were generally below the CCME's TEL of 34.1 ng/g and OMOE's lowest effect level (LEL) of 70 ng/g; however, they were consistent with the OMOE's no effect level (NEL) of 10 ng/g. The fca-SQTs derived using the BSAF as well as food chain multiplier (FCM) approach for a smaller scale system (Hamilton Harbour in Lake Ontario) corresponded well with average lakewide Lake Ontario fca-SQTs. This analysis provides approximate sediment concentrations necessary for reducing fish consumption advisories for each of the Canadian Great Lakes and emphasizes the impacts of historical lake sediment contamination on fish advisories. We believe that this approach merits consideration in sediment guideline development.

Considerations for the regulation of polychlorinated dibenzodioxins, furans (PCDD/Fs) and biphenyls (PCBs) in liver

Introduction There is increasing evidence that liver produced from farm animals such as cows, pigs and sheep may breach European Union regulatory limits for dioxin concentrations even when the livestock are given compliant animal feed and are exposed only to normal background levels of dioxin contamination in the environment. The dioxin concentrations in other commonly consumed tissues such as muscle, fat, kidney, etc., from the same animals will typically be well within regulatory limits. When dioxin limits were initially proposed and eventually established by the European Union, almost a decade ago, they were based on a small data set available at the time, and were expressed on the basis of concentrations in fat in common with limits for other animal products (except for fish which were set on a whole weight basis because of seasonal and other variations in the lipid content of this species). Data generated for liver since the regulations came into force, suggest that dioxin concentrations in liver from certain types of animal are higher than were anticipated. Objectives We set out to establish whether liver on retail sale produced using normal farming practices was likely to contain dioxins and polychlorinated biphenyls above regulatory limits and to consider whether or not the regulations were appropriate. Method We did this by analysing samples of liver obtained from retail outlets. Results and Conclusion Nine of the 22 ovine (sheep) liver analysed and reported here exceeded the European Union limit for liver and all 10 of the venison liver exceeded this value, although venison liver is not covered by the regulation. The high cost of compliance monitoring, together with the likely proportion of non-compliances, could amount to a de facto ban on the sale of ovine (sheep) liver even in the absence of a risk to consumer health. The preferred solution would be to revise the existing dioxin and total TEQ limits set out in Commission Regulation (European Commission) No. 1881/2006 to reflect the levels that are normally found, with the addition of precautionary advice to consumers if this is considered necessary.

Toxicity comparison of chlorinated and brominated dibenzo- p-dioxins and dibenzofurans in industrial source samples by HRGC/HRMS and enzyme immunoassay

Limited information is available on the applicability of polychlorinated dibenzo- p-dioxin/furan (PCDD/F) toxicity assays to their brominated counterparts: polybrominated dibenzo- p-dioxins/furans (PBDDs/Fs). We estimated the toxicity of mixtures of chlorinated, brominated, and mixed bromochloro-dioxins and -furan (PBCDDs/Fs) laboratory standards using a chemically-activated luciferase gene expression cell bioassay (CALUX). The relative effects potency (REP) values obtained were comparable to the World Health Organization (WHO) toxic equivalency factors (TEFs) and in agreement with the concept of additive congener toxicity of mixtures of dioxins and furans. Enzyme immunoassay (EIA)-based toxic equivalents (TEQs), however, showed overestimation for PCDDs/Fs (0–4 orders of magnitudes higher) and underestimation for PBDDs/Fs (0–1 orders of magnitude lower) when compared to high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS)-based TEQ calculation (using WHO TEFs) in samples from an industrial source line. No correlation was found between the EIA and the HRGC/HRMS data, which could be attributed to differences in homologue-specific cross-reactivity responses, sample matrix type, and presence of other compounds competing for antibody binding in the immunoassay.

Human uptake of persistent chemicals from contaminated soil: PCDD/Fs and PCBs

Trace amounts of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are ubiquitous in the environment. Because of industrial activity, other human activities, and accidents, higher concentrations of these chemicals may be present in soil, in residential and recreational areas. Human uptake of these chemicals from such soils has been assumed by regulators, and people contacting such soils may be concerned about potential adverse health effects. Accordingly, clean up levels have been set by state and federal agencies. Whether and to what extent humans actually take up these chemicals from soil is the focus of this review. Since humans are also exposed to PCDD/Fs and PCBs in food and air, their concentrations in these media are presented. We find that their presence in soils is unlikely to increase human body burdens.

Levels and congener profiles of PCDD/Fs, PCBs and PBDEs in seafood from China

A nationwide investigation into polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in market seafood was conducted for the first time in this study. Total PCDD/F concentrations in fatty fish ranged from 0.13 to 8.64 pg g −1 wet weight (mean 2.05 pg g −1 wet weight), total PCB concentrations ranged from 38.9 to 3514 pg g −1 wet weight (mean 1133 pg g −1 wet weight), and total PBDE concentrations ranged from 42.8 to 913 pg g −1 wet weight (mean 322 pg g −1 wet weight). Corresponding mean toxicity equivalent (TEQ) values for total PCDD/F and dioxin-like PCB were 0.25 pg g −1 wet weight (WHO 98-TEQ) and 0.32 pg g −1 wet weight (WHO 98-TEQ), respectively. OCDD, PCB-138 and PBDE-47 were the dominant compounds according to their respective congeners. WHO 98-TEQ PCDD/PCDF/PCB for fatty fish and shell fish were 0.60 and 0.070 pg g −1 wet weight, respectively, lower than the standard set by the European Commission. The contamination levels and profiles were compared with those documented in previous publications.

Persistent Organic Pollutants in Fish Oil Supplements on the Canadian Market: Polychlorinated Dibenzo‐p‐Dioxins, Dibenzofurans, and Polybrominated Diphenyl Ethers

Canadians are interested in improving their diet through the consumption of fish oil food supplements, which are marketed to be rich in omega-3 fatty acids. Convenience samples of omega-3 enriched dietary supplements (n = 30) were collected in Vancouver, Canada, between 2005 and 2007. All of the omega-3 supplements were analyzed for polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polybrominated diphenyl ethers (PBDEs) and, although every sample was found to contain detectable residues of PBDEs, only 24 samples were found to have PCDD/F concentrations above the level of detection. PCDD/F concentrations ranged from 0.05 pg TEQ/g lipid to 45.7 pg TEQ/g lipid in salmon and shark oils, respectively. Maximum PBDE concentrations similarly were observed in shark oil (113 microg/kg lipid), however, most supplements had concentrations below 5 microg/kg lipid. Average PCDD/F and PBDE intake estimates, based on consumption of maximum supplement dose following product label recommendations, were 4.32 pg TEQ/d and 25.1 ng/d lipid, respectively.

PCB and PCDD/F in sediments and mussels of the Istanbul strait (Turkey)

Sediment and mussel samples collected along the coasts of the Istanbul strait and an island in Marmara Sea (Turkey) were analyzed for six indicator polychlorinated biphenyl (PCB), 12 dioxin-like PCB (dl-PCB) and 17 polychlorinated dibenzo-p-dioxin/furan (PCDD/F) congeners. Samples contained different concentrations of PCBs and among these, congeners 153, 75, 105 and 118 in sediments and congeners 153, 138 and 118 in mussels were most abundant. The concentration levels of total PCBs and PCDD/Fs in sediments ranged from 17.9 to 539 746 pg g −1 dm and 2.04 to 60.5 pg g −1 dm, respectively. The total WHO-TEQ values ranged between 0.01 and 17.8 pg g −1 dm in sediments, and 0.98 and 1.01 pg g −1 ww in mussels. None of the sediment and mussel samples analyzed exceeded the limits suggested in the sediment quality guideline and safe values set by the European Community for seafood intended for human consumption, respectively.

A national survey of polychlorinated dioxins, furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in human milk in China

The study examined the levels of dioxin-like compounds in 24 pooled samples that were comprised of 1237 individual human milk samples from 12 provinces of China. The samples were taken in different regions to evaluate the body burden of these contaminants and assess their health risk to breast-feeding infants of China. The pooled samples were analyzed for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) congeners. The population of the provinces involved in this study accounts for approximately 50% of the total Chinese population. The range of upper-bound total-TEQ in samples was from 2.59 pg TEQ g −1 lipid to 9.92 pg TEQ g −1 lipid with a mean of 5.42 pg TEQ g −1 lipid and a median of 5.11 pg TEQ g −1 lipid. PCDD/Fs-TEQ and total-TEQ in human milk from rural areas were lower than those from urban areas. The positive correlations were found between total-TEQ level in human milk and the consumption of aquatic food and meat respectively. The mean estimated daily intake of PCDD/Fs and dl-PCBs by infants was 28.0 pg TEQ kg −1 bw per day with a range from 14.2 pg TEQ kg −1 bw per day to 48.6 pg TEQ kg −1 bw per day. In the study, both the TEQ body burden of the sample population and estimated daily TEQ intake of breast-feeding infants were lower than those of developed countries. Continuous surveillance on PCDD/Fs and dl-PCBs levels in human milk is needed to correctly evaluate both the environmental impact and human health risk in China.

Polychlorinated dibenzo- p-dioxins/furans and polychlorinated biphenyls in human adipose tissue from Zhejiang Province, China

This is the first report on polychlorinated dibenzo- p-dioxin/furan (PCDD/F) and polychlorinated biphenyl (PCB) contamination of human adipose tissue from China. A total of 24 human adipose tissue samples from a general population in Zhejiang Province were analyzed for PCDD/F and PCB by high-resolution gas chromatography–high-resolution mass spectrometry. Total PCDD/F concentrations in human adipose tissue ranged from 33.9 to 504 pg g −1 lipid (mean 108 pg g −1 lipid). Corresponding values for dioxin-like PCBs ranged from 4.1 to 125 ng g −1 lipid (mean 32.8 ng g −1 lipid). Mean total WHO toxicity equivalent (TEQ) values for PCDD/Fs and PCBs in human adipose tissue were 9.22 and 16.2 pg g −1 lipid, respectively. OCDD was the dominant PCDD/F congener, and 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD accounted for more than 70% of the WHO PCDD/F TEQ. In all samples, PCB-118, PCB-156 and PCB-105 were the main PCB congeners. PCB-153 concentrations were the highest of all indicator PCBs (mean 52.5 ng g −1 lipid). The contamination levels and profiles are compared with those reported for European and Asian countries.