Polybrominated Diphenyl Ethers Emission Research Articles

Mitigation of PBDE net discharge in hazardous waste thermal treatment system through reintroducion of sludge and fly ash into GASMILD operations

The presence of polybrominated diphenyl ethers (PBDEs) in consumer products, waste treatment processes, and treated ashes poses a significant environmental threat. Due to the lack of research on the removal of PBDEs during waste incineration, this study investigated the effectiveness of a Hazardous Waste Thermal Treatment System (HAWTTS) utilizing reburning of sludge and fly ash (SFA) with gasification-moderate or intense low-oxygen dilution (GASMILD) combustion for PBDE removal. The closed-loop treatment of sludge and ash within the HAWTTS provides a potential pathway for near-zero PBDE emissions. The GASMILD combustion addresses potential combustion issues associated with fly ash recirculation. The system achieved an impressive overall removal efficiency of 98.4% for PBDEs, with minimal stack emissions (2.45 ng/Nm³) and a negative net discharge rate (−1.02 μg/h). GASMILD combustion played a crucial role (92.7%–97.6% destruction) in addressing challenges associated with high-moisture feedstocks and SFA residues. Debromination of highly brominated PBDEs occurred within the incinerator, resulting in an increased proportion of lower brominated PBDEs in the bottom slag compared to the feedstock. Air Pollution Control Devices (APCDs) achieved a total PBDE removal efficiency of 74.4%. However, the hydrophobic nature of PBDEs limited removal efficiency in scrubbers (36.0%) and cyclonic demisters (37.86%). This study demonstrates that reintroducing SFA into the GASMILD combustion process offers an effective and environmentally sustainable strategy for reducing net PBDE levels in hazardous waste. This approach also provides additional benefits such as energy conservation, reduced carbon emissions, and lower operating costs associated with secondary treatment of thermally treated byproducts.

Polybrominated diphenyl ethers in student dormitory microenvironments: Concentrations, sources, and human exposure

Microenvironments, such as student dormitories, differ from general residential environments. They are characterized by small spaces, poor air circulation, high personnel densities, and electronic products, such as computers that are turned on for extended periods, leading to increased pollution concentrations. The limited space and poor air circulation reduce migration of contaminants, such as polybrominated diphenyl ethers (PBDEs), making it easier for PBDEs to accumulate. However, few studies have been conducted on small group dwellings, including student dormitory dwellings. We collected dust samples from student dormitories of a university to analyze the characteristics and traceability of PBDEs in dormitory microenvironments. The results showed that PBDE congeners were widely present in university dormitories and the order of median concentration of ∑10PBDEs was as follows: male old-fashioned dormitory (273 ng/g) > female four-person dormitory (132 ng/g) > female two-person dormitory (132 ng/g) > male two-person dormitory (96.2 ng/g) > female old-fashioned dormitory (91.6 ng/g) > male four-person apartment (51.8 ng/g). BDE-209 was the most abundant PBDE congener, followed by BDE-47, and BDE-28. PBDEs were also found in typical electrical appliances, with higher concentrations in laptops than in desktops, and higher concentrations in desktops than in idle ones. According to Spearman correlation and Principal Component Analysis (PCA), we also found that boards and wallpaper materials were common sources of contamination in the microenvironment of student dormitories, and that female dormitories had more sources of PBDE emissions. Human exposure to PBDEs in students is below the US Environmental Protection Agency reference dose. Although exposure to PBDEs generated in dormitories does not pose a significant health risk, the potential hazards of PBDEs to the reagent environment remain to be investigated.

Optimal emission reductions pathway for polybrominated diphenyl ethers in typical household e-waste dismantling products

Waste printed circuit boards (WPCBs) and waste epoxy resin powder (WERP) generated after crushing are the most crucial hazardous materials in the recycling process of household e-waste. In this study, a sustainable treatment approach was established in response to the drawbacks of traditional treatment methods. The baseline and hypothetical scenarios were as follows: (1) scenario 1 (S1): WPCBs mechanical treatment, WERP safe landfill; (2) scenario 2 (S2): WPCBs mechanical treatment, WERP imitation stone bricks production. Based on the material flow analysis and comprehensive evaluation, the most profitable and environmentally friendly scenario was selected and assumed to be promoted in Jiangsu area and China from 2013 to 2029. The analysis result showed that S2 had the best economic performance and polybrominated diphenyl ethers (PBDEs) emission reductions potential. S2 is the best option that can gradually replace the traditional recycling model. With the promotion of S2, China would reduce the emissions of PBDEs by 700.8 kg. Meanwhile, it could save $542.2 million in WERP landfill costs, produce 1260.2 kt of imitation stone bricks, and generate $2308.5 million in economic benefits. In conclusion, this study can offer a new idea for dismantling products treatment of household e-waste and provide scientific knowledge to improve the sustainable management.

Environmental signature and health risk assessment of polybrominated diphenyl ethers (PBDEs) emitted from a landfill fire in Santiago de Chile

Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in building materials, electronics, furnishings, vehicles, airplanes, plastics, polyurethane foams, and textiles for many years. Currently, the primary commercial mixtures, penta-, octa-, and deca-BDE, are globally restricted. Still, products containing PBDEs are expected to impact waste management and the environment for many years. In January 2016, an open fire in the Santa Marta landfill close to Santiago de Chile affected the city and surroundings. The fire caused several acute health effects and an increase in emergency hospitalizations. We measured PBDE levels in the areas affected by the fire in the air (gaseous and particulate) and soil, and PBDE emissions were estimated using a dispersion model. The results showed an increase in PBDE concentrations by a factor of 2–4 one day after the start of the fire. However, PBDE concentrations measured after the fire in PM10 and the gas phase were considered low compared to other regions. Interestingly, PBDEs’ patterns differed across the sites; however, BDE209 was the dominant congener for all environmental matrices. A preliminary risk assessment was conducted using the daily exposure dose (DED) by air inhalation estimation. The results showed low DED values for adults and children and suggested no direct health risk due to PBDE exposure. This study brings new data useful for future solid waste management initiatives in the country.

Ecological unequal exchange: quantifying emissions of toxic chemicals embodied in the global trade of chemicals, products, and waste

Ecologically unequal exchange arises if more developed economies (‘core’) shift the environmental burden of their consumption and capital accumulation to less developed economies (‘periphery’/‘semi-core’). Here we demonstrate that human populations in core regions can benefit from the use of products containing toxic chemicals while transferring to the periphery the risk of human and ecological exposure to emissions associated with manufacturing and waste disposal. We use a global scale substance flow analysis approach to quantify the emissions of polybrominated diphenyl ethers (PBDEs), a group of flame retardants added to consumer products, that are embodied in the trade of chemicals, products and wastes between seven world regions over the 2000–2020 time period. We find that core regions have off-loaded PBDE emissions, mostly associated with the disposal of electrical and electronic waste (e-waste), to semi-core and peripheral regions in mainland China and the Global South. In core regions this results in small emissions that mostly occur during the product use phase, whereas in peripheral regions emissions are much higher and dominated by end of life disposal. The transfer of toxic chemical emissions between core and periphery can be quantified and should be accounted for when appraising the costs and benefits of global trade relationships.

Control of extreme brominated persistent organic pollutant emissions from start-ups of waste-to-energy incinerators

Unlike chlorinated persistent organic pollutants (Cl-POPs), few studies have investigated the emissions of brominated POPs (Br-POPs), including polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PBDEs), from start-up processes of municipal solid waste incinerators (MSWIs). Presently, there are no studies published on Br-POP control during this period. This study found that start-up processes could contribute to at least 27%, 55%, and 2% PBDD/F, PBB, and PBDE emissions of an entire year of MSWI operations. High PBDD/F and PBDE emission rates were observed at the beginning of the start-up, indicating that control measures should be conducted before or at the beginning of the start-ups. PBBs behaved like Cl-POPs with high emission rates observed at the POP-formation temperature window (250–450 °C). Unlike Cl-POPs, inhibiting adsorptive memory effects by cleaning the accumulated ash was the most effective control strategy for PBDD/F and PBDE emissions, accounting for 72.8% and 51.3% of total reductions, respectively. Contrarily, inhibiting Br-POP formation by cleaning the accumulated ash and shortening the residence time of the flue gas in 250–450 °C contributed to the highest PBB reduction (67.5%). Overall, the control strategies reduced PBDD/F and PBB emissions by >97% and PBDEs by 61%. This study shows that PBDD/Fs and PBDEs behave differently from their chlorinated equivalents and require different control strategies. In conclusion, the control strategies proposed can reduce Br-POP emissions during start-up successfully, and they require no modifications to existing control devices.

Emission of PAHs, PCBs, PBDEs and heavy metals in air, water and soil around a waste plastic recycling factory in an industrial park, Eastern China

Environmental information in recovery of waste plastic in a certificated factory in industrial park in Eastern China is provided in this paper. The process involves raw material storage, washing, closed crushing, closed regeneration, product storage, and waste storage. Particulate matters, heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyis (PCBs), and polybrominated diphenyl ethers (PBDEs) emitted from the production process are analyzed. A total of 25 atmospheric samples, 6 soil samples, and 2 water samples are sampled in and around the factory. The following conclusions could be concluded: (1) the concentrations of Cu and Pb are significantly higher than that of Ni, Cr and Cd in total suspended particulate matters; (2) PHE, DghiP, NAP and FLA are the main PAHs components in the air; PHE, FLA, DghiP, NAP, and PYR are the main congeners of PAHs in both washing wastewater and surface water; PHE, NAP, FLA, and CHR are the major congeners in the soil samples; (3) PCB-18, PCB-17 and PCB-31,28 are the main congeners in the air samples; PCB-70 and PCB-110 are the main congeners in soil samples; PCB-49 and PCB-52 are the main congeners in both surface water and washing wastewater; (4) DBDPE and BDE-209 are the main congeners for the all air, water and soil samples. Washing process and crushing process are identified as the main sources of all the above pollutants releases, and management strategies are provided to reduce the pollutants emission and the environmental hazardous caused by the waste plastic recovery process.

Polybrominated diphenyl ethers in indoor and outdoor dust from Southeast Asia: An updated review on contamination status, human exposure, and future perspectives.

Contamination status, potential emission sources, environmental fate, and human exposure risk of polybrominated diphenyl ethers (PBDEs) are reviewed for indoor and outdoor dust from Southeast Asian countries, under an international comparison point of view. PBDEs have been widely detected in house, workplace, car, and road dust samples collected from Indonesia, Philippines, Singapore, Thailand, and Vietnam. The highest PBDE levels up to hundreds of μg/g were found in settled dust from some e-waste processing areas in Thailand and Vietnam. Concentrations of PBDEs in house, car, and road dust from this region were generally lower than those reported in China and Western developed countries. BDE-209 was the most predominant congener in almost all analyzed samples, reflecting the widespread application of materials and products treated with commercial deca-BDE mixtures in this region. The market demand and application rate of commercial PBDE mixtures in Southeast Asia were lower than those documented for other regions in the world. As a result, PBDE contamination levels in the environments (e.g., indoor and outdoor dust) and associated risks in these countries were not significantly high. However, more attention should be paid to informal processing activities and management strategies for modern wastes such as e-waste, plastics, and end-of-life vehicles. There exist several knowledge gaps about spatiotemporal trends, potential sources, risk assessment, inventory, management, and legislation regarding PBDEs in dust from this region, which should be filled by additional comprehensive, detailed studies with relevant inter-country/regional monitoring schemes.

Exposure and health risk assessment of secondary contaminants closely related to brominated flame retardants (BFRs): Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in human milk in shanghai

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), as the secondary environmental pollutants of the widely used brominated flame retardants (BFRs), possess the similar physicochemical and toxic properties as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). However, studies on human body exposure to them are extremely limited. In this study, forty human milk samples collected in Shanghai were measured for 13 PBDD/F congeners using gas chromatography-high resolution mass spectrometry (GC-HRMS), to investigate their exposure level and characteristics, potential source and corresponding health risks to breastfed infants. The results showed no PBDDs but three PBDF congeners including 2,3,7,8-TBDF, 1,2,3,4,6,7,8-HpBDF and OBDF (mean concentration (detection rates) are 3.2 pg/g (72.5%), 9.5 pg/g (100%) and 28 pg/g (67.5%), respectively) were detected. The average toxic equivalent quantity (TEQ, 0.42 pg/g lw) presented the highest concentration level compared to other regions reported. The contribution of PBDFs to the total TEQ of PBDD/Fs and PCDD/Fs is 6.8%. The correlation between PBDD/Fs and age or dietary habits was not observed, which normally existed in their chlorinated analogues-PCDD/Fs. Significant correlations were observed between PBDFs and highly brominated polybrominated diphenyl ethers (PBDEs) (especially for BDE 183 and BDE 209). The correlation between PCDD/Fs and PBDFs was not observed except 2,3,7,8-TBDF. The high PBDFs exposure in Shanghai may originate from the emission of PBDEs and/or non-PBDE BFRs in environment, according to the consistency of the environmental data previously reported. The average estimated dietary intakes (EDI) for breastfed infants is 2.0 pg TEQ/kg·bw/day (0.13–13 pg TEQ/kg·bw/day), within the range of the tolerable daily intake (TDI) for TCDD (1–4 pg TEQ/kg·bw/day) suggested by the World Health Organization (WHO). However, given the high toxicity of PBDD/Fs, the potential health risks of these pollutants for breastfed infants should be of concern.

Polybrominated diphenyl ethers and organochloride pesticides in the organic matter of air suspended particles in Mexico valley: A diagnostic to evaluate public policies

The presence of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) was analysed in air particulate matter ≤ 2.5 μm (PM2.5) and ≤10 μm (PM10) collected in the Metropolitan Zone of Mexico Valley (MZMV), during 2013 and 2014, respectively. Spatial and seasonal distributions of PM and their organic content named solvent extracted organic matter (SEOM) were determined. PM mass concentration and SEOM/PM ratios were compared with previous studies in 2006 in Mexico City. PM2.5 concentration was like found in 2006, however, PM10 decreased ∼43%. The SEOM/PM10 ratio was kept constant, suggesting a decrease in SEOM as well as PM10 emitted from natural sources, probably as a result of changes in the land use due to urban growth. A decrease ∼50% SEOM/PM2.5 ratio was observed in the same period, linked to adequate strategies and public policies applied by the local and federal governments to control the organic matter emitted from anthropogenic sources.Seven out of sixteen OCPs and five out of six PBDEs were found. The most common POPs were endosulfan I, endosulfan II, endosulfan sulfate, BDE-47 and BDE-99, present on >90% of the sampling days. OCPs in PM2.5 and PBDEs in PM10 showed seasonal variability. Higher PBDEs concentration in both particle sizes were observed at east and southeast of the MZMV, where one of the biggest landfills and wastewater treatment plants are located. OCPs in PM10 were mainly emitted from agricultural areas located to the southwest, southeast and east of the MZMV. OCPs in PM2.5 showed a regional contribution from the north and introduced into the valley. OCP degradation products were dominant over native OCPs, indicating no fresh OCP use. POPs comparison with other cities was made. Agreements and commissions created by the Mexican government reduced OCPs emissions, however, more effort must be made to control PBDE emission sources.

High spatial resolution analysis of polybrominated diphenyl ethers (PBDEs) using transplanted lichen Evernia prunastri: A case study in central Italy

The ability of transplanted lichen Evernia (E.) prunastri (L.) to act as a high spatial biomonitoring tool for 14 polybrominated diphenyl ethers (PBDEs) was evaluated at 23 monitoring sites in a very polluted area in central Italy. The selected area is characterized by the presence of numerous emission sources, such as waste-to-energy plant, steel plant, vehicular traffic, and domestic heating. Transplanted E. prunastri proved to be a useful tool to biomonitor PBDEs, due to its ability to bioaccumulate individual congeners in varying concentrations in relation to the strength of the emission sources present over the territory. PBDEs levels widely ranged from 132 to 24,237 ng kg−1 dry weight, according to the sources of emission located around the monitoring sites. The highest concentrations were detected at the sites close to the municipal solid waste incinerator, steel plant, and high busy roads, confirming their important role as PBDEs emissions sources.

Fate and migration of polybrominated diphenyl ethers in a workshop for waste printed circuit board de-soldering.

Polybrominated diphenyl ethers (PBDEs) are released from the recycling process of PBDE-containing waste printed circuit board (WPCB), but studies on the mechanism of PBDE emission and migration are limited. In this study, PBDE concentrations in particulate matter (PM), dust, and fumes collected in a pilot-scale workshop for the WPCB de-soldering process were measured, and PBDE emission after gas treatment was estimated. The results showed that the mean concentrations of ∑8PBDEs in TSP and PM2.5 in the workshop were 20.3 ng/m3 (24.7 μg/g) and 16.1 ng/m3 (115 μg/g), respectively. In practice, the fumes containing gaseous and particulate PBDEs were treated by the combination of alkaline solution absorption and activated carbon adsorption. Compared to PBDE concentration in workshop floor dust (2680 ng/g), PBDE concentrations in solution scum (68,000 ng/g) and hood inside dust (20,200 ng/g) were condensed. The concentrations of ∑6PBDEs at the stack outlet (416 pg/m3) after gas treatment were lower than those in the stack pipe (1310 pg/m3) and hood inside (7440 pg/m3). The PBDEs in fumes were removed through physical adsorption of alkaline solution and activated carbon, and solution scum constituted the main mass discharges of PBDEs. The emission factor of PBDEs at the stack outlet was 47.3 ng ∑6PBDEs/kg WPCB. As a result, the WPCB de-soldering process is an important source of PBDE pollution, and gas treatment of solution absorption and activated carbon adsorption can reduce PBDE emission to some extent.

Emission characteristics of polybrominated diphenyl ethers from the thermal disassembly of waste printed circuit boards

Thermal disassembly is prevalently applied for the removal of electronic components on waste printed circuit boards (WPCBs), and temperature is an important factor influencing the pollutant emission process. The emission characteristics of polybrominated diphenyl ethers (PBDEs) to the environment under thermal stress were investigated by conducting both bench-scale experiments and pilot-scale experiments over a temperature range from 100 to 260 °C. Bench-scale experiments showed that the emission factors (EFs) for ∑39PBDEs from WPCB powder were obviously higher than those from WPCB fragments. Mono-to tri-BDEs predominated the PBDEs emission at each temperature, and the EFs for the mono-to tri-BDEs from WPCB powder ranged from 232 to 3280 ng/g, respectively. Pilot-scale experiments were done to study the particulate matter (PM) and PBDEs emitted from WPCBs mounted with electronic components using a thermal disassembly machine. The mass of the PM and PBDEs released from WPCBs during heating increased with increasing temperature. A bimodal distribution pattern for the PM with peaks at diameters of 0.4–0.7 and 5.8–9.0 μm was observed. The values of the EFs for ∑39PBDEs varied from 6.41 to 674 ng/g, which were comparable with those calculated from WPCB fragments in the bench-scale experiments. The mass distribution of the ∑39PBDEs in the PM predominated in the size fraction of >9.0 μm and 0.7–1.1 μm at 100 and 260 °C, respectively. The highly brominated PBDEs (hexa- and hepta-BDEs) had a mass median aerodynamic diameter (MMAD) greater than 2.5 μm, while the lightly brominated PBDEs (mono-to penta-BDEs) were mainly distributed in finer particles, with a MMAD of less than 2.5 μm. The particle size distribution of PBDEs was significantly correlated with the distribution of organic carbon (OC) in PM. All these results can provide basic data for gas pollution related to PBDEs and its control for electronic waste recycling.

Polyurethane foam-based passive air sampling for simultaneous determination of POP- and PAH-related compounds: A case study in informal waste processing and urban areas, northern Vietnam

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromobiphenyl (BB-153), novel brominated flame retardants (NBFRs), and unsubstituted/methylated polycyclic aromatic hydrocarbons (PAHs/Me-PAHs) were simultaneously monitored in the air samples collected from Vietnamese urban and vehicular waste processing areas by using polyurethane foam-based passive air sampling (PUF–PAS) method. Concentrations (pg m−3) of organic pollutants decreased in the order: PAHs (median 29,000; range 5100–100,000) > Me-PAHs (6000; 1000–33,000) > PCBs (480; 170–1100) > PBDEs (11; 5.3–86) > NBFRs (0.20; n. d. – 51) > BB-153 (n.d.). The difference in total PCB and PBDE concentrations between the urban and waste processing air samples was not statistically significant. Meanwhile, levels of PAHs, Me-PAHs, benzo [a]pyrene equivalents (BaP-EQs), and toxic equivalents of dioxin-like PCBs (WHO-TEQs) were much higher in the waste processing sites. This is the first report on the abundance of mono- and di-CBs (notably CB-11) in the air from a developing country, suggesting their roles as emerging and ubiquitous air pollutants. Our results have indicated potential sources of specific organic pollutants such as dioxin-like PCBs, PAHs, and Me-PAHs from improper treatment of end-of-life vehicles and other vehicle related materials (e.g., waste oils and rubber tires), as well as current emission of PCBs and PBDEs in the urban area in Vietnam. Further atmospheric monitoring studies should be conducted in this developing country that cover both legacy and emerging contaminants with a focus on areas affected by rapid urbanization and informal waste processing activities.

Occurrence, air-sea exchange, and gas-particle partitioning of atmospheric polybrominated diphenyl ethers from East Asia to the Northwest Pacific Ocean

The occurrence, air–sea exchange, and gas–particle partitioning of polybrominated diphenyl ethers (PBDEs) were analyzed during a 2015 research expedition from the East China Sea (ECS) to the open Northwest Pacific Ocean (NWP). The sum of 13 PBDEs (Σ13PBDEs) in air and surface seawater varied in the range of 0.54–14.5.pg m−3 and 0.60–13.5 pg L−1, respectively, with the highest concentrations observed in the ECS. The Clausius–Clapeyron approach and air mass origin analysis indicated that continued primary emissions of PBDEs, particularly BDE-209, from East Asian sources governed the spatial variability of air PBDEs over the NWP through long-range atmospheric transport (LRAT). Net air-to-seawater gas deposition of PBDEs was evidenced based on the fugacity calculation with sum fluxes of seven selected PBDEs ranging from −45 to −582 pg m−2 d−1. Following the substantial advection of aerosol phase BDE-209 over the ECS, dry particle deposition dominated the input pathway of PBDEs into the ECS, whereas in the open NWP, relatively free from the influence of the land emissions, fluxes in PBDE absorption and in dry particle deposition were comparable. This suggests an impact of continental outflow on the fate of atmospheric PBDEs over the NWP. Regarding gas–particle partitioning, PBDEs over the NWP were obviously absorbed into continental organic aerosols during atmospheric transport, except for BDE-209, which tended to remain within the steady state.

Effects of temperature on the emission of particulate matter, polycyclic aromatic hydrocarbons, and polybrominated diphenyl ethers from the thermal treatment of printed wiring boards.

The effects of temperature on the emission of pollutants during the thermal treatment of electronic waste have rarely been investigated. The emission of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) from the thermal treatment of printed wiring boards was investigated over a temperature range of 320-600 °C. The emission factors (EFs) were determined to be within 1.6-7.6 g/kg, 2.23-11.9 μg/g, and 0.9-5.5 μg/g, respectively. High temperatures increased the formation of PAHs and CO, but decreased the emission of PBDEs, PM, and organic carbon. A temperature of 480 °C was determined to be optimal. Low-molecular-weight components were the dominant PAH species. The compositional profiles of PBDEs were clearly observed to vary with the temperature. Small particles (< 2.1 μm) that were more affected by temperature were dominant in PM, particle-bound PAHs, and PBDEs at all temperatures. High temperature increased the EFs of gaseous PAHs but had no remarkable effect on those of particulate PAHs. The freshly emitted PAHs primarily existed in the particulate phase at low temperatures, while the gaseous phase PAHs became prevailing at ≥ 520 °C. The particulate PBDEs were more susceptible to temperature and overwhelmingly dominant over the entire temperature range considered.

Polybrominated Diphenylethers (PBDEs) in ambient air samples at the electronic waste (e-waste) reclamation site.

Polybrominated Diphenylethers (PBDEs) were used as flame-retardants in various building materials, plastic and other polymers, airplanes, electronics etc. All or some of their congeners have been already banned in many countries, due to their persistency and adverse health effects. In this study, we are focusing on the e-wastes as a source of emission of PBDEs in ambient air during reclamation processes. The ambient air particulate matter (PM) samples were collected at and near e-waste reclamation site in Bangkok, Thailand. Results showed the presence of various homologues viz: tri, tetra, penta, hexa, and hepta-PBDEs on both PM2.5 and Total Suspended Particle (TSP) samples. The comparison of samples as a function of distance from reclamation site indicated elevated levels of PBDEs in the close proximity to e-waste site. Interestingly, a shift in the congener pattern was observed with lower brominated PBDEs being more prevalent on nearby off-site samples as compared to the PM collected at the e-waste site. The total penta-PBDEs concentration is about double on e-waste site PM2.5 compared to control site samples. For TSP, tetra, penta, and hepta-PBDEs congeners are at higher concentrations at e-waste sites and its vicinity compared to reference sites. Overall, a clear trend can be observed indicating a debromination of PBDEs to more toxic tri and tetra congeners during reclamation process and PBDEs are being translocated from treated materials to ambient air PM. BDE 30 congener is identified as a specific marker of thermal reclamation processes of e-wastes as a most stable degradation product. This work indicates potential hazards related to the reclamation of e-wastes and remediation of sites containing PBDEs. In particular, thermal treatment methods can lead to congener transformation and increased emissions of more toxic lower-brominated congeners.

Concentrations and occupational exposure assessment of polybrominated diphenyl ethers in modern Chinese e-waste dismantling workshops

In this work, the concentrations of polybrominated diphenyl ethers (PBDEs) were determined in air, dust and fly ash samples from three legal waste electrical and electronic equipment dismantling plants with strict pollution controls. The risks posed by PBDEs to workers at the plants were assessed. The atmospheric concentrations of PBDEs in the different e-waste recycling workshops were 0.58–2.89 × 103 ng/m3, and predominantly distributed in the particle phase (90.7%–99.9%). The concentrations of the PBDEs in the floor dust and fly ash samples from bag-type dust collectors in different workshops were 2.39–125 μg/g, 5.84–128 μg/g, respectively. The contributions of BDE-209 in air, floor dust and fly ash samples were 84.0%–97.9%, 11.2%–95.3% and 74.0%–94.9%, respectively, indicating that deca-BDE commercial formulations were their major sources. Daily exposure to PBDEs was also lower than has been found for workers in other recycling workshops. Human exposures to BDE-47, BDE-99, BDE-153, and BDE-209 were all below the levels considered to pose appreciable risks. Dust ingestion was the main exposure route for manual recyclers, and inhalation was the main exposure route for waste transportation workers. The results of this study indicate that PBDEs emissions and risks are lower in modern, legal e-waste recycling facilities with effective pollution controls. However, the effectiveness of the pollution controls need to be further researched in plastic crushing areas.

Contamination of polybrominated diphenyl ethers (PBDEs) in urban mangroves of Southern China

Mangroves are threatened due to urban development and human activities in coastal regions. Four urban mangroves in Shenzhen (rapidly developing city of China) were selected according to urban functional zoning, namely, Shajing mangrove (SJM) and Xixiang mangrove (XXM) featured with industry district, Futian mangrove (FTM) and Baguang mangrove (BGM) featured with central business district and ecological preserve. Eight BDE congeners (BDE-28, -47, -99, -100, -153, -154, -183, and -209) in mangrove sediments and leaves were determined. The highest level of BDE-209 in SJM was proximate to areas of point-source discharges of Dongbao River in Pearl River Estuary, China. Total organic carbon (TOC) was influential in BDE-209 accumulations in SJM, XXM, and FTM. Multiple variate analysis implied that PBDEs in SJM, XXM and FTM mainly composed of penta-, octa-, and deca-BDEs, with surface runoff to be the main contamination sources; while BGM was contaminated by penta- and octa-BDEs. Ecological risk of BDE-209 was high in SJM, with medium/negligible risk in the other urban mangroves. The transfers of BDE-209 from sediment to leaf were weak (BGM and FTM), improved (XXM), and restricted (SJM), respectively. This is the first reports of spatial distribution and bioaccumulation of PBDEs in urban mangroves featured with different urban functional zonings. More attention is required to reduce emission of PBDEs into the environment and manage PBDEs contamination in urban mangroves.

Insight into the local source of polybrominated diphenyl ethers in the developing Tibetan Plateau: The composition and transport around the Lhasa landfill

In the background region of the Tibetan Plateau (TP), the rapid urbanization probably results in the massive generation of persistent organic pollutants (POPs), which lacks monitoring and evaluation. Since landfill could serve as an important sink of the locally used POPs, the analysis of POPs in the Tibetan landfill area might help us to understand the source composition and their transport in the TP. In this study, the concentration variations of polybrominated diphenyl ethers (PBDEs) in five soil profiles and seven surficial sediments around the largest Tibetan landfill were investigated. The total concentrations of PBDEs ranged from 128 to 1219 ng/kg in soils, and from 447 to 7295 ng/kg in sediments. The dominance of nona- and deca-BDEs possibly indicated the wide usage of deca-BDE as flame retardant in the TP. The vertical and spatial distribution patterns of PBDEs within soils plausibly revealed their main transport pathways by atmospheric dispersion and leachate seepage from landfill. Based on principal components analysis and multiple linear regression, these two pathways were estimated to account for 61% and 39% of the total concentrations, respectively. Additionally, the spatial and vertical distributions of octa-to deca-BDEs within soils were significantly influenced by soil particle size. Although the PBDEs inventory in the study area was comparatively low, the rapid urbanization in the TP might dramatically accelerate the PBDE emissions in the future. This study firstly introduced the presence of local PBDEs in the TP, and the inventory already influenced the surrounding environment. Once involved in the regional cycle of the TP, the local source of PBDEs from waste might significantly serve to raise background level resulting otherwise primarily from long-range atmospheric transport.