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

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.

Spatiotemporal transitions of organophosphate esters (OPEs) and brominated flame retardants (BFRs) in sediments from the Pearl River Delta, China

Recent regulations on the use of brominated flame retardants (BFRs, especially polybrominated diphenyl ethers, PBDEs) have led a sharp increase in the use of organophosphate esters (OPEs), which have become the subject of widespread environmental concern. To gain insights into their environmental transitions, we investigated the spatiotemporal trends and sources of 25 OPEs and 23 BFRs (21 PBDEs and two alternative BFRs) in sediments from the Pearl River Delta (PRD), the second economic/industrial region of China. Among them, PBDEs showed higher mean concentrations than OPEs and alt-BFRs in PRD sediments, a continual increase in most PRD areas, and positive correlations with most local socioeconomic parameters. The source analysis results indicated that all of these changes resulted from the substantial use/stock of PBDEs (especially deca-BDE) in this region, and BDE-209 displayed debromination in most sediments. OPEs demonstrated obvious increases in sediments from all major PRD rivers, especially those located in less-developed regions. This distribution might be related to the large-scale industry relocation from the central PRD area to its vicinities. Unexpectedly, decabromodiphenyl ethane (DBDPE), an important deca-BDE substitute, presented considerable declines in the PRD sediments while several novel OPEs showed considerably high proportions, especially aryl-substituted OPEs, which merit further screening analysis.

Human health risks from brominated flame retardants and polycyclic aromatic hydrocarbons in indoor dust

Exposure to dust particles containing toxic compounds is linked to serious health outcomes, including cancer. The purpose of this study was to determine if indoor dust from houses and cars contained harmful levels of brominated flame retardants (polybrominated diphenyl ethers, PBDEs) and polycyclic aromatic hydrocarbons (PAHs), and to assess their potential toxicity to adults and children. In Kuwait, the median concentration of total PBDEs (Ʃ14- PBDEs) was 408.55 μg PBDEs/kg dust in houses and twice as high in cars (838.52 μg PBDEs/kg dust), while total PAHs (Ʃ16-PAHs) were similar in houses (992.81 μg PAHs/kg) and cars (900.42 μg PAHs/kg). The PBDEs and PAHs concentrations in indoor dust were related to house age and square footage, car model year, and natural ventilation. Furthermore, a higher PBDEs concentration was associated with electronic devices that operate continuously, furniture containing foam treated with PBDEs, and cars that are parked outdoors, since PBDEs tend to be volatilized under these conditions. The PAHs concentration in indoor dust increased with smoking and proximity to major roads and industrial facilities, which are major PAHs sources. The hazard quotient and total cancer risk for PBDEs in indoor dust were within safe limits, but indoor dust with higher PAHs concentrations had hazard quotients from 5.51 to 11.23 and total cancer risk of 10^-3 for adults and children. We conclude that exposure to PAHs-contaminated indoor dust from houses and cars where smoking occurs can increase the cancer risk of adults and children.

Environmental characteristics and formations of polybrominated dibenzo-p-dioxins and dibenzofurans

Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) are emerging persistent organic pollutants (POPs) that have similar or higher toxicities than the notorious dioxins. Toxicities, formation mechanisms, and environmental fates of PBDD/Fs are lacking because accurate quantification, especially of higher brominated congeners, is challenging. PBDD/F analysis is difficult because of photolysis and thermal degradation and interference from polybrominated diphenyl ethers. Here, literatures on PBDD/F analysis and environmental occurrences are reviewed to improve our understanding of PBDD/F environmental pollution and human exposure levels. Although PBDD/Fs behave similarly to dioxins, different congener profiles between PBDD/Fs and dioxins in the environment indicates their different sources and formation mechanisms. Herein, potential sources and formation mechanisms of PBDD/Fs were critically discussed, and current knowledge gaps and future directions for PBDD/F research are highlighted. An understanding of PBDD/F formation pathways will allow for development of synergistic control strategies for PBDD/Fs, dioxins, and other dioxin-like POPs.

A comparison of developmental toxicity of brominated and halogen-free flame retardant on zebrafish

Brominated diphenyl ethers (BDEs) are halogenated flame retardants. Several concerns related to persistence and toxicity of BDEs have been resulted in a growing need of BDEs replacement. The use of halogen-free flame retardants (HFFR) has increased as a safer alternative, but little information is available on their toxic potential for environmental health and for developing organisms. Therefore, the aim of this study was to evaluate and compare the toxicity of three congeners of BDEs (BDE-47, BDE-99 and BDE-154) with an HFFR (aluminum diethylphosphinate, ALPI) on zebrafish (Danio rerio) by assessing endpoints of lethality, sub-lethality and teratogenicity at the earlier stages of development. The highest tested concentration of BDE-47 (12.1 mg/L) induced pericardium and yolk sac edemas that first appeared at 48 h post-fertilization (hpf) and then were mostly reabsorbed until 144 hpf. BDE-47 also showed a slight but non-significant tendency to affect swim bladder inflation. The rate of edemas increased in a concentration-dependent manner after exposure to BDE-99, but there were no significant differences. In addition, the congener BDE-99 also presented a slight and non-significant effect on swim bladder inflation, but only at the highest concentration tested. Regarding BDE-154 exposure, the rate of edemas and swim bladder inflation were not affected. Finally, in all ALPI exposure concentrations (0.003 up to 30 mg/L), no sub-lethal or teratogenic effects were observed on developing organisms until 96 hpf. Although further studies are needed, our results demonstrate that when comparing the developmental toxicity induced by flame retardants in zebrafish, the HFFR ALPI may be considered a more suitable alternative to BDE-47.

Polybrominated diphenyl ethers in the environment and human external and internal exposure in China: A review

Polybrominated diphenyl ethers (PBDEs) are widely used as brominated flame retardants. Because of their toxicity and persistence, some PBDEs were restricted under the Stockholm Convention in 2009. Since then, many studies have been carried out on PBDEs in China and in many other countries. In the present review, the occurrences and contamination of PBDEs in air, water, sediment, soil, biota and daily food, human blood, hair, and other human tissues in China are comprehensively reviewed and described. The human exposure pathways and associated health risks of PBDEs are summarized. The data showed no obvious differences between North and South China, but concentrations from West China were generally lower than in East China, which can be mainly attributed to the production and widespread use of PBDEs in eastern regions. High levels of PBDEs were generally observed in the PBDE production facilities (e.g., Jiangsu Province and Shandong Province, East China) and e-waste recycling sites (Taizhou City, Zhejiang Province, East China, and Guiyu City and Qingyuan City, both located in Guangdong Province, South China) and large cities, whereas low levels were detected in rural and less-developed areas, especially in remote regions such as the Tibetan Plateau. Deca-BDE is generally the major congener. Existing problems for PBDE investigations in China are revealed, and further studies are also discussed and anticipated. In particular, non-invasive matrices such as hair should be more thoroughly studied; more accurate estimations of human exposure and health risks should be performed, such as adding bioaccessibility or bioavailability to human exposure assessments; and the degradation products and metabolites of PBDEs in human bodies should receive more attention. More investigations should be carried out to evaluate the quantitative relationships between internal and external exposure so as to provide a scientific basis for ensuring human health.

Assessment of Occupational Exposure to Organic Flame Retardants: A Systematic Review

BACKGROUND

Flame retardants (FRs) are widespread in common goods, and workers in some industries can be exposed to high concentrations. Numerous studies describe occupational exposure to FRs, but the diversity of methods and of reported results renders their interpretation difficult for researchers, occupational hygienists, and decision makers.

OBJECTIVES

The objectives of this paper are to compile and summarize the scientific knowledge on occupational exposure to FRs as well as to identify research gaps and to formulate recommendations.

METHODS

Five databases were consulted for this systematic literature review (Embase, Medline [Pubmed], Global health, Web of Science, and Google Scholar), with terms related to occupational exposure and to FRs. Selected studies report quantitative measurements of exposure to organic FRs in a workplace, either in air, dust, or in workers' biological fluids. The Preferred Reporting Items for Systematic reviews and Meta-Analyses statement guidelines were followed.

RESULTS

The search yielded 1540 published articles, of which 58 were retained. The most frequently sampled FRs were polybrominated diphenyl ethers and novel brominated FRs. Offices and electronic waste recycling facilities were the most studied occupational settings, and the highest reported exposures were found in the latter, as well as in manufacturing of printed circuit boards, in aircrafts, and in firefighters. There were recurrent methodological issues, such as unstandardized and ill-described air and dust sampling, as well as deficient statistical analyses.

CONCLUSIONS

This review offers several recommendations. Workplaces such as electronic waste recycling or manufacturing of electronics as well as firefighters and aircraft personnel should be granted more attention from researchers and industrial hygienists. Methodical and standardized occupational exposure assessment approaches should be employed, and data analysis and reporting should be more systematic. Finally, more research is needed on newer chemical classes of FRs, on occupational exposure pathways, and on airborne FR particle distribution.

Particle-phase concentrations and sources of legacy and novel flame retardants in outdoor and indoor environments across Spain

Levels of particle-phase legacy polybrominated diphenyl ethers (PBDEs), and novel brominated and chlorinated flame retardants, such as decabromodiphenyl ethane (DBDPE) and Dechlorane Plus (DP), were measured in ambient outdoor air, indoor workplace air and indoor dust, in different locations across Spain. PBDE concentrations were generally higher in outdoor ambient air samples than in indoor air, ranging between 1.18 and 28.6 pg m^-3, while DP was the main flame retardant (FR) in indoor air (2.90-42.6 pg m^-3). A different behavior of legacy versus novel FRs was observed in all the environments and matrices considered, which seemed to indicate a progressive replacement of the former. Although the emission sources could not be fully identified, certain evidences suggested that high outdoor PBDE concentrations could be associated with old goods in landfills and recycling centers, while high indoor DP concentrations were linked to the presence of new electronic devices. A direct impact of land use on outdoor atmospheric DP concentrations was observed, with DP concentrations correlating with high density of buildings within a city. In addition, DP concentrations outdoors correlated with inorganic species with FR properties (e.g., Cr, Cu). Significant differences in the fraction of anti-DP to the total DP (F_anti ratio) were observed between indoor air (PM_2.5) and dust (PM₁₀), which could be related with: a) a dependence on particle size, suggesting a higher relative abundance of the anti-isomer in PM₁₀ than in PM_2.5, while similar concentrations were recorded for the syn-isomer; b) a higher deposition rate of the anti-isomer compared to the syn-isomer; and/or c) a more accentuated preferential degradation of the anti-isomer linked to artificial light or other agents coexisting in the air. The detectable presence of all the FR families analyzed in indoor air and dust points to the importance of monitoring these compounds in order to minimize human exposure.

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.

Exposure to polybrominated diphenyl ethers (PBDEs) in American and Canadian workers: Biomonitoring data from two national surveys

Polybrominated diphenyl ethers (PBDEs) are flame retardants commonly found in many household and industrial products. They can be detected in the serum of the general population, and in even higher concentrations in workers of certain industries, due to an additional occupational exposure. The purpose of this analysis is to determine background exposure levels of PBDEs in the general working population, using national surveys where working status was self-reported. Participants aged 20-65 were selected from the 2003-2004 U.S. National Health and Nutrition Examination Survey (n=1141) and the 2007-2009 Canadian Health Measures Survey (n=1337). Only four congeners were detected in at least 25% of samples for both surveys: BDE47, 99, 100 and 153. NHANES workers had a geometric mean (GM [95% C.I.]) BDE47 concentration of 20.9ng/g lipids [19.3, 22.7], and CHMS workers, 11.4ng/g lipids [10.8, 12.1]. PBDE levels were not statistically significantly different between workers and non-workers, except for BDE153 in CHMS. Among workers, women had a significantly lower concentration of BDE153 than men in both surveys (% change [95% C.I.] with 1ng/g lipid increase: -33.4% [-49.0, -12.9] in NHANES, -18.8% [-27.5, - 8.9] in CHMS), in regressions adjusted for age, body mass index, smoking status, ethnicity and education. CHMS workers in the Information, finance, real-estate, and education industry group had significantly higher BDE47 concentrations than non-workers. These results indicate a high exposure to PBDEs in two North American countries, compared to data from other national surveys. The heterogeneity of the data did not permit a clear-cut distinction between workers and non-workers. Sex differences noted with BDE153 are consistent with those reported in other human exposure assessments and animal studies. Overall, industry-specific concentrations showed no particular pattern across both surveys. Despite some limitations, these data provide a useful estimate of the background exposure to PBDEs in American and Canadian workers.

Polybrominated diphenyl ether flame retardant concentrations in faeces from young children in Queensland, Australia and associations with environmental and behavioural factors

The aim of our study was to investigate children's exposure to the flame retardants polybrominated diphenyl ethers (PBDEs) by analysing faecal content, a non-invasive matrix, as well as responses to an exposure-assessment questionnaire. A convenience sample of 61 parents with children (aged >3 months to <2 years) completed an online pre-tested questionnaire and provided faecal samples for analysis by high resolution gas chromatography/mass spectrometry. BDE-209 was the dominant congener in faecal samples adjusted to 8.3ng/g dry weight (dw), with >80% samples above the limit of detection (LOD). BDE-47 (0.23ng/g dw) and BDE-153 (0.03ng/g dw) were each detected above the LOD in approximately 60% of samples. Age was associated with BDE-47 (-7%/month) and BDE-153 (-12%/month) concentrations in faeces, but not BDE-209. Other variables associated with PBDE concentrations included features of the home (carpet, pets) and behaviour (hand-to-mouth, removing shoes, using a car sunshade, frequency of walks outdoors). However, given the small sample size of this study additional research is required to confirm these findings. In this study we demonstrated that faeces may be a viable alternative to monitor human exposure to PBDEs, but further validation studies are required.

Airborne persistent toxic substances (PTSs) in China: occurrence and its implication associated with air pollution

In recent years, China suffered from extensive air pollution due to the rapidly expanding economic and industrial developments. Its severe impact on human health has raised great concern currently. Persistent toxic substances (PTSs), a large group of environmental pollutants, have also received much attention due to their adverse effects on both the ecosystem and public health. However, limited studies have been conducted to reveal the airborne PTSs associated with air pollution at the national scale in China. In this review, we summarized the occurrence and variation of airborne PTSs in China, especially in megacities. These PTSs included polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), halogenated flame retardants (HFRs), perfluorinated compounds (PFCs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and heavy metals. The implication of their occurrence associated with air pollution was discussed, and the emission source of these chemicals was concluded. Most reviewed studies have been conducted in east and south China with more developed economy and industry. Severe contamination of airborne PTSs generally occurred in megacities with large populations, such as Guangzhou, Shanghai and Beijing. However, the summarized results suggested that industrial production and product consumption are the major sources of most PTSs in the urban environment, while unintentional emission during anthropogenic activities is an important contributor to airborne PTSs. It is important that fine particles serve as a major carrier of most airborne PTSs, which facilitates the long-range atmospheric transport (LRAT) of PTSs, and therefore, increases the exposure risk of the human body to these pollutants. This implied that not only the concentration and chemical composition of fine particles but also the absorbed PTSs are of particular concern when air pollution occurs.