Polybrominated Dibenzo-p-dioxins/furans Research Articles

Halogenated aromatic pollutants in routine animal-derived food of south China: Occurrence, sources, and dietary intake risks

Halogenated aromatic pollutants (HAPs) including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) exhibit diverse toxicities and bio-accumulation in animals, thereby imposing risks on human via animal-derived food (ADF) consumption. Here we examined these HAPs in routine ADFs from South China and observed that PBDEs and PCBs showed statistically higher concentrations than PCDD/Fs and PBDD/Fs. PCDD/Fs and PCBs in these ADFs were mainly from the polluted feed and habitat of animals, except PCDD/Fs in egg, which additionally underwent selective biotransformation/progeny transfer after the maternal intake of PCDD/F-polluted stuff. PBDEs and PBDD/Fs were mostly derived from the extensive use of deca-BDE and their polluted environments. Significant interspecific differences were mainly observed for DL-PCBs and partly for PBDD/Fs and PBDEs, which might be caused by their distinct transferability/biodegradability in animals and the different living habit and habitat of animals. The dietary intake doses (DIDs) of these HAPs via ADF consumption were all highest for toddlers, then teenagers and adults. Milk, egg, and fish contributed most to the DIDs and risks for toddlers and teenagers, which results of several cities exceeded the recommended thresholds and illustrated noteworthy risks. Pork, fish, and egg were the top three risk contributors for adults, which carcinogenic and non-carcinogenic risks were both acceptable. Notably, PBDD/Fs showed the lowest concentrations but highest contributions to the total risks of these HAPs, thereby meriting continuous attention.

Evaluation of hexabromocyclododecane (HBCD), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) outflows during the destruction of HBCD wastes in a hazardous waste incinerator

This paper presents an evaluation of hexabromocyclododecane (HBCD), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) outflows during the destruction of HBCD waste stockpiles in IZAYDAS Hazardous Waste Incinerator (HWI) in Kocaeli, Türkiye. HBCD wastes containing 100 % pure HBCD were in 25 kg packages with 63 % Br content were co-incinerated in a 3-day test burn with average feed rate of 26 kg/h. HBCD, PBDD/Fs and PCDD/Fs were measured in the outlet streams to quantify the amount of unintended POPs releases associated with the processing of HBCD waste and to observe the POP removal performance of air pollution control equipment (APCE) of the incinerator. Total mass outflow rate of HBCDs is calculated as 2.6 g/day, corresponding to destruction efficiency of 99.9996 %. Total toxicity of the brominated dioxins was measured as 0.00044 ng TEQ/Nm3 on average, while highly brominated congeners are dominant. PCDD/F concentrations in the outflow streams during HBCD test burns are produced similar congener distributions with those given in the previous studies, with the dominance of 7,8-chlorinated congeners. Mass flows in the outlet streams indicated that the efficiency of ESP and wet scrubbers for the removal of PCDD/Fs and HBCDs. Flue gas concentrations of PCDD/Fs, HBCDs and PBDD/Fs obtained in HBCD burn test indicated that burning HBCD wastes cause no significant emissions as operational parameters and total halogen content in the menu are kept within the incinerator limits.

Free radical formation via BDE-209 thermolysis in the precalciner of a cement kiln: Simulation and DFT study

To deeply understand the formation mechanism of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) in the thermal disposal process of polybrominated diphenyl ether (PBDE)-containing waste, this paper studied the formation pathways of key intermediates (free radicals, FRs) in the formation process of PBDD/Fs. BDE-209, the most common PBDE in the environment, was selected as the object of study to analyze FR formation by simulating the key conditions such as temperature (850 °C) and Fe-based materials when PBDE-containing waste entering cement kiln precalciner. Electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) calculations were used to study the reaction. The result of simulation experiments revealed carbon-centered radicals, and DMPO-OH analysis further confirmed the generation of FRs. The findings confirmed previous calculations predicting the existence of radical intermediates during the formation of PBDD/Fs from BDE-209. DFT calculations revealed the existence of an inner ortho-position CBr bond in BDE-209. The priority order of the bond breaking of BDE-209 was ether bond, inner ortho-position CBr bond, and outside ortho-position CBr bond. BDE-209 can further form three kinds of FRs, namely, oxygen-centered radicals of single benzene rings, carbon-centered radicals of single benzene rings, and carbon-centered radicals of double benzene rings. The specific processes of FR formation were inferred: high-temperature homogeneous cleavage of chemical bonds, electron transfer, and chemisorption, where electron transfer and chemisorption may be more important pathways. The proposed inner ortho-position cleavage within BDE-209 provides new insights into the degradation of PBDEs and the formation of PBDD/Fs; the results regarding BDE-209 generation radicals further elucidate the synthesis mechanism of dioxins, which is important for controlling dioxin generation and emission during the treatment and disposal of waste containing PBDEs.

Occurrence and carcinogenic potential of airborne PBDD/Fs and PCDD/Fs around a large-scale municipal solid waste incinerator: A long-term passive air sampling study

Municipal solid waste incinerator (MSWI) not only is deemed one of the uppermost sources of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), but also produces substantial amount of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) owing to the existence of brominated flame retardants (BFRs) in the waste. So far, however, PBDD/Fs in the vicinal environments of MSWI and their associated risks remain rarely studied. Based on a one-year passive air sampling (PAS) scheme, we investigated airborne PBDD/Fs and PCDD/Fs around a large-scale MSWI that has been operated for multi-years. Both the concentrations of PBDD/Fs and PCDD/Fs showed spatially decreasing trends with the distance away from the MSWI, confirming the influence of the MSWI on the dioxin levels in its ambient air. But its influence on PBDD/Fs was less because PBDD/Fs exhibit lower volatility and therefore lower gaseous concentrations than PCDD/Fs. Compared to the existing global data of airborne PCDD/Fs and PBDD/Fs, our data of the MSWI vicinity were at medium levels, despite PAS samples only represent the concentrations of gaseous dioxins in theory. The seasonal data suggest that meteorological conditions exerted apparent influences over the concentrations and sources of airborne dioxins around the MSWI. As for PCDD/Fs, the MSWI was diagnosed as their uppermost source, followed by local traffic and volatilization/deposition. Whereas the top three PBDD/F sources were related to PBDEs, bromophenol/bromobenzene, and traffic vehicles, respectively. The bioassay-derived TEQs based on the aryl hydrocarbon receptor activation of airborne dioxins around the MSWI were one or two orders of magnitudes higher than their concentration-based TEQs, and the corresponding carcinogenic risks at some MSWI-vicinal sites exceeded the acceptable threshold proposed by the U. S. EPA (10−6 ∼ 10−4) and deserve continuous attention.

Polybrominated Dibenzo-p-dioxins/Furans (PBDD/Fs) and Diphenyl Ethers (PBDEs) in the Indoor and Outdoor of Gymnasiums

It is still unknown whether the organobromine compounds in the indoor environment of the gyms would affect human health. This study tried to investigate PM2.5 and indoor-dust levels of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and diphenyl ethers (PBDEs) in the gyms and then to further assess the health risks of the gym users and employees who were exposed to these organobromines through inhalation and ingestion. The gyms were to be examined for PBDD/DF/DEs on PM2.5 indoors and outdoors and in indoor dust. The results showed that indoor-dust, indoor PM2.5, and outdoor PM2.5 levels of PBDD/Fs were 37.8 ± 13.7 pg WHO2005-TEQ g-1 and 0.00650 ± 0.00340 and 0.00469 ± 0.00101 pg WHO2005-TEQ m-3, respectively, in the gyms, while for PBDEs, they were 2670 ± 2330 ng g-1 and 9.54 ± 4.68, and 8.27 ± 3.46 pg m-3. The PBDEs levels observed in this study were relatively lower when compared with the current global data of PM2.5 and indoor dust levels of PBDEs. The observed PM2.5-bound PBDDFs and PBDEs in the indoor gyms were not related to those in the outdoor gyms, but certain PBDE level was associated with PBDD/Fs in the indoor dust of the gyms. It suggested that the outdoor emission might not be correlated with the indoor emission, whereas indoor-dust PBDD/Fs might be converted from the pyrolysis of indoor-dust PBDEs. To assess the risks, the non-dietary daily intakes of PBDEs and PBDD/Fs were estimated as 1.61-2.11 × 10-7 and 4.15-5.42 × 10-13 mg kg b.w.-1 day-1, respectively, in the employees and 5.04-6.58 × 10-8 and 1.29-1.69 ×10-13 mg kg b.w.-1 day-1, respectively, in the gym users. The values didn’t exceed the critical levels when the gym employees and users were assessed by non-cancer and cancer risks of organobromines. In conclusion, although the gym employees and users inhaled more PM2.5 during the exercise, the risks of PBDD/DE/DFs were still under the acceptable levels.

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) in soil around municipal solid waste incinerator: A comparison with polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs)

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) share similar toxicities and thermal origins, e.g., municipal solid waste incinerator (MSWI). Recently, PBDD/Fs from MSWI attracted rising concern because their important precursors, i.e., brominated flame retardants (BFRs), were frequently found in various wastes for landfill or MSWI feedstock. So far, however, little is known about PBDD/Fs and their associated risks in the vicinal environments of MSWI. Here we analyzed PBDD/Fs and PCDD/Fs in 29 soil samples collected around a multiyear large-scale MSWI, and compared their spatial distributions, sources and risks. PBDD/Fs demonstrated comparable concentrations and toxic equivalent quantities (TEQs) to PCDD/Fs in these samples. Spatially, both the concentrations of PBDD/Fs and PCDD/Fs decreased outwards from the MSWI, and exhibited significant linear correlations with the distances from the MSWI in the southeast downwind soil, suggesting the influence of the MSWI on its vicinal soil environment. However, the existence of other dioxin sources concealed its influence beyond 6 km. PBDD/Fs in the soils were characterized by highly-brominated PBDFs, especially Octa-BDF, and their sources were diagnosed as the MSWI and diesel exhaust; PCDD/Fs, however, were dominated by highly-chlorinated PCDDs, particularly Octa-CDD, and were contributed individually or jointly by the MSWI, automobile exhaust and pentachlorophenol (PCP)/Na-PCP. The non-carcinogenic risks of dioxins in all the soil samples were acceptable, but their carcinogenic risks in 17% of the samples were unacceptable. These samples were all located close to the MSWI and highways, therefore, the land use of these two high-risk zones should be cautiously planed.

Bromination of Carbon and Formation of PBDD/Fs by Copper Bromide in Oxidative Thermal Process

Brominated aromatic compounds are unintentionally generated during various thermal processes, including municipal solid waste incineration, electric-waste open burning, and secondary copper smelting. Copper (Cu) plays an important role in the formation of brominated aromatic compounds. In the present study, the thermochemical behaviors of Cu and Br in model samples, including copper bromide (CuBr2) and activated carbon, were studied using in situ X-ray absorption near-edge structure (XANES) and thermogravimetry. Quantification of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) was also conducted by gas chromatograph–high resolution mass spectrometer. Three key reactions were identified: (i) the reduction of CuBr2 to CuBr (room temperature to 300 °C), (ii) the generation of Br bonded with aromatic carbon (150–350 °C), and (iii) the oxidation of copper (>350 °C). Maximum amounts of PBDD/Fs were found in residual solid phase after heating at 300 °C. The analytical results indicated the direct bromination of aromatic carbon by the debromination of copper bromides (I, II) and that CuBr and CuO acted as catalysts in the oxidation of the carbon matrix. The bromination mechanisms revealed in this study are essential to the de novo formation of PBDD/Fs and other brominated aromatic compounds.

Levels of PCDD/Fs, PBDEs, and PBDD/Fs in Breast Milk from Southern Taiwan.

This study investigates the congener-specific concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) in 25 breast milk samples from southern Taiwan. Most investigated congeners in Taiwanese breast milk are detectable except for PBDD/Fs. The geometric means of PCDD/Fs and PBDEs in the breast milk are 2.44pg WHO2005-TEQ/g lipid and 2810pg/g lipid. Several PCDD/F and PBDE congeners were highly correlated to each other like 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF (r = 0.919, p < 0.001). The longest duration of menstruation could be predicted by BDE-153 (β = 0.252) and 1,2,3,4,6,7,8-HpCDF (β = 0.345) with adjustment of confounders using a multiple stepwise linear regression model (r = 0.963, p < 0.001).

Levels of Non-PBDE Halogenated Fire Retardants and Brominated Dioxins and their Toxicological Effects in Indoor Environments - A Review

Non-polybrominated diphenyl ether (non-PBDE) halogenated fire retardants (HFRs) such as new or novel brominated fire retardants (NBFRs) and dechlorane plus (DP) have been widely spread in the environment and recognized as emerging persistent organic pollutants (POPs) in the recent years, mainly due to the continuous increase in their global demand, especially after the worldwide restrictions on PBDE use. Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) are the unintentional byproducts of PBDE commercial formulations in the indoor environment. Although HFRs, including NBFRs, DP, and PBDD/Fs, are ubiquitous in the indoor environment due to the large-volume release from the surfaces of consumer products, only a few in vitro and in vivo studies have addressed their toxic effects. In this review article, global data on NBFRs, including decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEH-TEBP), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), DP, including syn-DP and anti-DP, and PBDD/Fs in indoor aerosol and dust are summarized from recent literature. Based on the gathered data, indoor dust is a major sink for indoor contamination and is of great concern due to the fact that dust ingestion is one of the primary routes for human exposure to these chemicals. Lastly, the toxic effects of NBFRs, DP, and PBDD/Fs identified in in vitro and in vivo studies are summarized and discussed based on the current published reports. However, there is still a lack of sufficient toxicity data for assessing their risks. Future works are encouraged to focus on indoor PM2.5-bound HFR levels to further evaluate their toxic effects on human health.

Dust levels of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) in the Taiwanese elementary school classrooms: Assessment of the risk to school-age children

Elementary school classroom dust is an important source of exposure to polybrominated dibenzo-p-dioxins/furans and diphenyl ethers (PBDD/DF/DEs) for school-age children. Our goal is thus to investigate concentrations of PBDD/DF/DEs in elementary school classroom dust to further assess the impact on school-age children via ingestion. The dust from classrooms, including both normal (NR) and computer classrooms (CR), was collected from six urban and four rural schools. Fourteen PBDEs and twelve PBDD/Fs were measured using high-resolution gas-chromatography/high-resolution mass-spectrometry. The mean levels of Σ14PBDEs in NR and CR dust from the urban classrooms were 370 and 2510ng/g and those whose dust from the rural classrooms were 464 and 1780ng/g. The means of ΣPBDD/Fs were 0.0401ng-WHO2005-TEQ/g (concentration: 4.72ng/g) in urban NR dust, 0.0636ng-WHO2005-TEQ/g (7.51ng/g) in urban CR dust, 0.0281ng-WHO2005TEQ/g (3.60ng/g) in rural NR dust, and 0.0474ng-WHO2005TEQ/g (6.28ng/g) in rural CR dust. The PBDEs pattern in NR dust was quite different from that in CR dust, but the PBDD/Fs patterns in NR and CR dust were similar. A linearly significant correlation coefficient (n=20, r=0.862, p<0.001) was found between ΣPBDEs and ΣPBDD/Fs in NR and CR dust, indicating that the PBDEs and PBDD/Fs in the dust may be from the same sources in the elementary school classrooms. This study assessed the risks (daily intake and cancer and non-cancer risks) of PBDEs and PBDD/Fs for the children from the classroom dust, and the calculated risk values did not exceed the related thresholds. With regard to the exposure scenarios for school-age children in an indoor environment, the results suggest that they might ingest more dust PBDD/DF/DEs in their homes than in the schools. In conclusion, the exposure of Taiwanese elementary school children to PBDD/DF/DEs via indoor dust was with a safe range based on our findings.

Particle size distribution of brominated flame retardants in house dust from Japan

Abstract The present study was conducted to examine the concentrations, profiles, and mass distributions of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) based on the particle sizes of house dust samples from five homes in Japan. After removal of impurities from house dust from vacuum cleaner bags, selected indoor dust samples were size fractionated (>2 mm, 1–2 mm, 0.5–1 mm, 250–500 μm, 106–250 μm, 53–106 μm, and 250 μm in size and fluffy dust were included. The conclusion is that particulate dust

Airborne polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and dechlorane plus (DP) in concentrated vehicle parking areas.

This study investigated polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and dechlorane plus (DP) in air around three concentrated vehicle parking areas (underground, indoor, and outdoor) in a metropolitan of South China. The parking areas showed higher concentrations of PBDEs, PBDD/Fs, and DP than their adjacent urban area or distinct congener/isomer profiles, which indicate their local emission sources. The highest PBDE and DP concentrations were found in the outdoor parking lot, which might be related to the heating effect of direct sunlight exposure. Multi-linear regression analysis results suggest that deca-BDEs without noticeable transformation contributed most to airborne PBDEs in all studied areas, followed by penta-BDEs. The statistically lower anti-DP fractions in the urban area than that of commercial product signified its degradation/transformation during transportation. Neither PBDEs nor vehicle exhaust contributed much to airborne PBDD/Fs in the parking areas. There were 68.1-100% of PBDEs, PBDD/Fs, and DP associated with particles. Logarithms of gas-particle distribution coefficients (K ps) of PBDEs were significantly linear-correlated with those of their sub-cooled vapor pressures (p Ls) and octanol-air partition coefficients (K OAs) in all studied areas. The daily inhalation doses of PBDEs, DP, and PBDD/Fs were individually estimated as 89.7-10,741, 2.05-39.4, and 0.12-4.17pgkg(-1)day(-1) for employees in the parking areas via Monte Carlo simulation.

Interplay of metals and bromine with dioxin-related compounds concentrated in e-waste open burning soil from Agbogbloshie in Accra, Ghana

Open burning of electronic waste (e-waste) releases various metals and organohalogen compounds in the environment. Here we investigated the interplay of metals (Cu, Pb, Zn, Fe, Co, and Sr) and bromine (Br) in the formation of dioxin-related compounds (DRCs), including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs), as well as non-regulated DRCs such as polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and their monobrominated PCDD/Fs in soils sampled from open burning e-waste sites at Agbogbloshie in Accra, Ghana. The predominant DRCs were PBDFs, PCDFs, PCDDs, and DL-PCBs. Statistical analyzes, X-ray absorption spectroscopy, and the PCDF/PCDD ratio suggested possible formation paths of PCDD/Fs and DL-PCBs by catalytic behaviors of copper chlorides (CuCl, CuCl2, and Cu2(OH)3Cl) and thermal breakdown of polyvinyl chloride. Predominant formation of brominated furans may be derived from electron transfer from intermediates of PBDE to copper, Cu(II) → Cu(I). Lead chloride also contributed to generate DRCs and may become highly bioaccessible through the open burning of e-waste. The main zinc species (ZnCl2 and ZnS) suggested a possible relationship to generate DRCs and specific zinc source such as tire burning. Cu, Pb, Zn, and Br contained in various e-wastes, wires/cables, plastics, and tires strongly influenced generation of many DRCs.

Simultaneous Determination of Polychlorinated Dibenzo- p -Dioxins/Furans, Polybrominated Dibenzo- p -Dioxins/Furans, Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers by Isotope Dilution-High Resolution Gas Chromatography-High Resolution Mass Spectrometry in Ambient Air

A method for simultaneous determination of polychlorinated dibenzo-p-dioxins/furan( PCDD/Fs),polybrominated dibenzo-p-dioxins/furans( PBDD/Fs),polychlorinated biphenyls( PCBs) and polybrominated diphenyl ethers( PBDEs) was established by using elution curve and fraction cut technology to eliminate the PCB and PBDE blank of interference and optimize the pre-treatment.The technology was developed using AutoSoxtec,acid silica gel column,multi-layered silica gel column and active carbon column.The sample recovery of sampling standards was in the range of 63%-100% and the recovery of internal standards was in the range of 52%-132%.The detection limits was between 6×10!4-1×10!2pg/m3,dicabromodiphenyl ether( BDE-209) was 0.3 pg/m3,which reached the US Environmental Protection Agency( EPA) standards.Air sample toxic equivalent quantity( TEQ)( PCDD/Fs,dl-PCBs) was between 0.216-0.949 pg/L WHOTEQ,TEQ( PBDD/Fs) was 0.0181-0.0462 pg/L WHO-TEQ,and PBDEs content was 105-132 pg/m3.

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.

Establishment and Application of the Co-analysis Method of PBDD/Fs and PCDD/Fs with Isotope Dilution High Resolution Gas Chromatography-High Resolution Mass Spectrometry in Ambient Air Samples

It has been known that the polybrominated dibenzo- p-dioxins/furans (PBDD/Fs) share similar or even higher toxicity and bio-accumulativity with polychlorinated dibenzo- p-dioxins/furans (PCDD/Fs). In this study, the co-analysis method of PBDD/Fs and PCDD/Fs with isotope dilution HRGC-HRMS was built based on the U.S. EPA Method 1613 and TO-9A. The samples were extracted and cleaned through acid silica gel bed, multi-layer silica gel column, and Florisil column, respectively. Eight 2,3,7,8-PBDD/Fs congeners and 17 congeners of 2,3,7,8-PCDD/Fs were quantified. The HRGC-HRMS conditions for PBDD/Fs were: EI + and SIM model with resolution ≥ 10000, electron emission energy of 50 eV, and filament current of 0.75 mA; DB-5 MS fused silica capillary column (30 m × 0.25 mm i.d., 0.1 μm) was used and the temperatures for injection, ion source, and transfer line were 250 °C, 250 °C, and 305 °C, respectively. The carrier gas was helium (1.0 ml min −1). The results showed that the relative standard deviations (RSDs) of parallel blank samples were ≤ 10.3% and the recoveries of PBDD/Fs and PCDD/Fs were in the range of 73%–112%. The average quantified values of the standard reference sample were in accordance with the certified values and the RSDs were ≤ 12.0%. The method detection limits were 0.25–1.5 pg μl −1 for PBDD/Fs and 1.5–5 pg μl −1 for PCDD/Fs. The concentrations of PBDD/Fs and PCDD/Fs were 1.01–2.43 pg per m 3 and 6.19–10.8 pg per m 3 for particulate samples, and 0.036–0.801 pg per m 3 and 1.37–12.1 pg per m 3 for gaseous samples of certain area, respectively. Compared with other areas in the world, the atmospheric dioxins pollution of the sampling area was at high level.

Relative differences in aryl hydrocarbon receptor‐mediated response for 18 polybrominated and mixed halogenated dibenzo‐P‐dioxins and ‐furans in cell lines from four different species

As a consequence of ubiquitous use of brominated organic chemicals, there is a concern for persistent or increasing environmental levels of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and mixed polychlorinated and polybrominated dibenzo-p-dioxins/furans (PXDD/Fs). Hence, there is a need to broaden the toxicological and environmental knowledge about these compounds, as a basis for risk assessment. In the study presented here, the relative potencies (REPs) for 18 PBDD/F and PXDD/ F congeners were determined in four dioxin-specific bioassays from different species: dioxin receptor chemically activated luciferase expression assay (DR-CALUX, rat hepatoma cells), TV101L (human hepatoma cells), and GPC.2D (guinea pig adenoma cells), as well as ethoxyresorufin-O-deethylase induction in the fish cell line RTL-W1 (rainbow trout liver cells). The bioassay specific REP factors presented here enable the assessment of the contribution from PBDD/Fs and PXDD/Fs to total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQs: toxic equivalents), using bioassay analysis. The PBDD/Fs were found to be equally potent as their chlorinated analogues in the three mammalian assays, whereas the PXDD/Fs showed relatively higher potencies. Of special concern were the 2,3,7,8-substituted penta- and tetrahalogenated congeners, for which mean REPs were > or =1. The 2-B-1,3,7,8-CDD (2-bromo-1,3,7,8-tetrachlorodibenzo-p-dioxin) was up to three times more potent than TCDD in individual experiments (on weight basis). The RTL-W1 was less sensitive to the tested compounds with overall 10-fold lower REPs than the mammalian cell lines. Although the REP factors exhibited species-specific differences, overall resembling rank orders of dioxin-like potency were obtained.

Formation of Polybrominated Dibenzo-p-dioxins/Furans (PBDDs/Fs) by the Pyrolysis of 2,4-Dibromophenol, 2,6-Dibromophenol, and 2,4,6-Tribromophenol

This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/ MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 o C, and decomposition by debromination at 500 o C resulted in less substituted bromodioxins.

Polyhalogenated dibenzo-p-dioxins and dibenzofurans in the exhaust air during textile processings

5 textile fmishing processes were investigated for polychlorinated dibenzo-p-dioxins/furans (PCDD/F), polybrominated dibenzo-p-dioxins/furans (PBDD/F) and mixed polychlorinated-brominated dibenzo-p-dioxins/furans (PBCDD/F). For the purpose of these investigations the complete balance — dioxin input from the raw textiles, output over the finished textiles and output through the air path — was done. In the exhaust air only small PXDD/F concentrations were detected. The textiles contain before and after the process nearly the same PCDD/F-concentrations. The concentrations of PBCDD/F arises after the process. Only the chimney depostions contain higher PCDD/F-concentrations up to 1 806.1 ng I-TE/kg, PBDD/F-concentrations up to 1572.6 ng/kg and PBCDD/F-concentrations up to 40 801.4 ng/kg.