Contamination by polybrominated diphenyl ethers of sediments from the Lake Maggiore basin (Italy and Switzerland)

Polybrominated diphenyl ethers (PBDEs) are characterized by chemical properties and toxicological profiles similar to other POPs (persistent organic pollutants) included in the EU Priority Pollutant List (2455/01/CE). However, limited data have been available for these compounds thus far for Italian freshwater abiotic matrices. Lake Maggiore basin, a heavily industrialized and densely populated area, was selected for studying PBDE contamination in Italy. PBDEs and OCs (organochlorine compounds) in the basin were quantified by analysing both sediment cores collected in 2005 from the lake and grab samples from the main tributaries and the emissary. Fourteen PBDEs, from tri-BDE to hepta-BDE congeners and BDE209, were compared with some organochlorine POPs (PCBs and DDTs) characterizing Lake Maggiore basin contamination. Analyses of tri-to hepta-BDEs, PCBs and DDTs were undertaken by GC-MS/MS, while BDE-209 was analysed by GC/ECD. Results showed a dominant presence of BDE-209 (>95% of SigmaBDE) and limited amounts of BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154. Lake core profiles highlighted a decreasing trend in PCB concentrations starting from the year 2000, while PBDEs showed greater concentrations after the beginning of the 1990s (up to 30 ng g(-1)d.w.). Among the tributaries, the Bardello and Boesio rivers were the most PBDE-contaminated (up to 290 ng g(-1)d.w.).     

Contamination and potential sources of polybrominated diphenyl ethers (PBDEs) in water and sediment from the artificial Lake Shihwa, Korea

Concentrations of polybrominated diphenyl ethers (PBDEs) were determined in water and sediment collected from the artificial Lake Shihwa and surrounding creeks. Total concentrations of 23 PBDE congeners in water and sediment ranged from 0.16 to 11.0 ng L⁻¹ and from 1.3 to 18 700 ng g⁻¹ dry weight, respectively. The concentrations of BDE 209 in water and sediment were 1-2 orders of magnitude higher than the total concentrations of other PBDE congeners. The concentrations of total PBDEs and BDE 209 in sediments were the highest compared to previously reported worldwide levels. The highest concentrations of PBDEs in water and sediments were found in creeks near industrial complexes. The PBDE concentrations gradually decreased with increasing distance from the creeks to the inshore and then offshore regions of the lake. BDE 209 was a major congener, accounting for 80% of the total PBDEs in water and sediment, consistent with a high consumption of deca-BDE for the brominated flame retardant market in Korea. Non-parametric multidimensional scaling ordination showed that surrounding creeks are major pathways of PBDE contamination associated with deca-BDE technical mixtures used in industrial complexes around Lake Shihwa. A significant correlation between total organic carbon and total PBDE concentration was found in sediments, and the correlation coefficients for individual PBDE congeners relatively increased from lower to higher brominated congeners.     

Levels and distributions of polybrominated diphenyl ethers,hexabromocyclododecane, and tetrabromobisphenol A in sediments from Taihu Lake,China

The concentrations and distribution of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA) were investigated in 28 sediment samples collected from Taihu Lake, Eastern China. The results showed that all three classes of compounds were detected in 28 sediment samples but that PBDEs were the main contaminants in the study area. The total PBDE concentrations ranged from 3.77 to 347 ng/g dry weight (dw) with a mean value of 72.8 ng/g dw, whereas the concentrations ranged from 0.168 to 2.66 and from 0.012 to 1.30 ng/g dw for HBCD and TBBPA, respectively. In all of the sediment samples, BDE-209 was the predominant congener, accounting for 95.9 to 98.6 % of the total PBDEs, which indicated that commercial mixtures of deca-BDEs were the main sources of PBDE contamination. Higher concentrations of PBDEs were found in samples collected from Meiliang Bay and Gonghu Bay near the inflow river, which suggested that inflow runoff might play an important role in the PBDE levels in Taihu Lake sediments.     

Polybrominated diphenyl ethers (PBDEs) in sediment and bivalves from Korean coastal waters

Concentrations of polybrominated diphenyl ethers (PBDEs) were determined in sediment and bivalves collected from 25 coastal locations in Korea. Twenty major PBDE congeners were found in all sediment and bivalve samples. SigmaPBDE20 concentrations ranged from 0.45 to 494 ng/g, dry weight (average 27.8 ng/g dry weight) in sediments, and from 0.38 to 9.19 ng/g, wet weight (average 2.94 ng/g wet weight) in bivalves. The highest concentrations were found at locations near industrial complexes and large harbors, suggesting that human activities contribute to PBDEs contamination in Korean coastal environment. PBDE concentrations measured in our study, excluding BDE congener 209 (deca-BDE), in sediment and bivalves were lower than those reported from other countries; whereas BDE 209 concentrations were comparable to or higher than those reported from other countries. The predominant PBDE congener in sediments and bivalves was deca-BDE, which accounted for >90% and >60% of the total PBDE concentrations in sediment and bivalves, respectively. This is consistent with high consumption of deca-BDE for the flame-retardant market in Korea. Significant correlations existed among BDEs 28, 47, 99, 100, 153 and 154 in sediments and bivalves; however, BDEs 183 and 209 showed little correlation compared with less highly brominated congeners.     

Polybrominated diphenyl ethers in house dust in Singapore

The use of polybrominated diphenyl ethers (PBDEs) as flame retardants in Singapore is not strictly regulated; therefore these compounds can be readily found in furniture, electronic devices, and building materials. This study was the first of its kind to be conducted in Singapore to measure concentrations of PBDEs in house dust. Samples were collected from 31 homes in various locations across the island-state of Singapore, and a total eight PBDEs congeners were measured. PBDEs were detected in all 31 dust samples and the number of BDE congener detected per home ranged between 3 and 8. The most abundant BDE congeners found were BDE 47, 99 and 209, with a median value of 20 ng g(-1) dust, 24 ng g(-1) dust and 1000 ng g(-1) dust, respectively. BDE 209 contributed 88% to the median of all the congeners, and BDE 47 and 99 contributed 1.8% and 3.5%, respectively. Different congener profiles were observed between this and studies conducted elsewhere, which is consistent with the use of different commercial PBDE around the world. No significant correlations between PBDE dust levels and residential characteristics (number of TVs and computers, floor area or flooring material) were observed. The daily intake of PBDEs via the inhalation pathway was estimated. House dust may be regarded as the most important exposure route of PBDEs for children.     

Polybrominated diphenyl ethers in surface sediments from principal watersheds of Shanghai, China: levels, distribution, influencing factors, and risk assessment

Fourteen and 17 sediment samples were collected from three main rivers of Shanghai in July and November, respectively. Eight polybrominated diphenyl ether (PBDE) congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) were detected in these samples to clarify the pollution status in the metropolis. Instrumental analyses showed that the concentrations of ∑₈PBDEs ranged from 10.97 to 64.05 ng/g dry weight (dw), with an average value of 29.71 ng/g dw. BDE-209 was the predominant congener accounting for more than 97 % of total PBDEs, followed by BDE-47 and BDE-99. Remarkable spatial and seasonal distributions of PBDE concentrations were observed, suggesting that local sources, seasonal climates, and hydrologic conditions might be the influencing factors. Moderate correlations (r ²?=?0.28–0.51, p?<?0.05) were found between total organic carbon and PBDEs, which indicated that organic carbon content influenced the distributions of PBDEs in sediment of Shanghai at some extent. Hazard quotients revealed PBDEs posed no potential risk to benthic organisms in the study area at present.     

Levels, compositions, and inventory of polybrominated diphenyl ethers in sewage sludge of Guangdong Province, South China

Polybrominated diphenyl ethers (PBDEs) were measured in sewage sludge samples collected from major wastewater treatment plants in Guangdong Province, South China. Concentrations of ∑₃₉PBDE (all 39 compounds including tri- to hepta- PBDE congeners except for BDE-209) ranged from 3.6 to 428 ng/g dw with a mean value of 67.4 ng/g dw and a median value of 25.9 ng/g dw, and those of BDE-209 ranged from 9.9 to 5,010 ng/g dw (mean 1,024 ng/g dw and median 824 ng/g dw). The PBDE mixtures detected were mainly comprised of penta-, octa-, and deca-BDEs, with deca-BDE as the dominant constituent. The most abundant congeners, excluding BDE-209, were BDE-47, BDE-99, and BDE-183. Good correlations were found among the concentrations of BDE-47, BDE-99, BDE-100, BDE-138, and BDE-154 (r?>?0.8). However, poor correlations were found between the concentrations of BDE-209 and all other congeners (r?<?0.3). This fact suggests that most tri- to hepta-BDEs detected did not originate from decomposition of deca-BDE. The estimated annual emission of ∑_allPBDEs, ∑₃₉PBDEs, penta-BDE, octa-BDE, and deca-BDE to the Pearl River Delta environment (PRD), based on the sludge samples analyzed, amounts to 232, 20.2, 5.5, 1.7, and 212 kg per year, implicating sewage sludge as a significant source of PBDEs to the PRD environment.     

Levels and distribution of polybrominated diphenyl ethers in plant, shellfish and sediment samples from Laizhou Bay in China

Polybrominated diphenyl ethers (PBDEs) are potentially harmful and persistent environmental pollutants. PBDEs concentrations are reported in plant, shellfish and sediment samples collected from Chinese Laizhou Bay. The summation operator(11)PBDE concentrations in plant and shellfish samples from Laizhou Bay were in the range of 70-5900ngg(-1) and 230-720ngg(-1) lipid, respectively. The summation operator(11)PBDEs concentrations in river sediment intervals samples ranged from 1.3 to 1800ng g(-1) dry weight. Pearson correlation analyses were performed on concentrations of PBDEs congeners of different sediment sample intervals. There were significant positive correlations for BDE 28 and BDE 100 (r=0.945, p<0.01), BDE 47 and BDE 99 (r=0.879, p<0.01), BDE 153 and BDE 154 (r=0.934, p<0.01), nona-BDEs and BDE 209 (r>0.934, p<0.01). BDE 209 was the predominant congener in all analyzed samples, consistent with the fact that deca-BDE technical mixtures are the dominant PBDEs product in Laizhou Bay. Data showed that PBDEs should be considered as an increasing pollution problem in the Laizhou Bay region.     

PBDEs in the supralittoral environment: the sandhopper Talitrus saltator (Montagu) as biomonitor?

In this study we evaluated the use of Talitrus saltator as biomonitor of polybrominated diphenyl ethers (PBDEs) contamination of the supralittoral zone of Mediterranean sandy shores, an area characterized by a strong input of contaminants but not yet investigated about the presence of these pollutants. We detected the presence of twenty PBDE congeners in amphipods and sand samples collected along the Tyrrhenian coast of central Italy. Eight congeners were detected in all samples. Among them, the BDE-209 was the most abundant in both amphipods and sand samples followed by BDE-99, BDE-153 and BDE-47 in animals, and BDE-99, BDE-47 and BDE-100 in sediment. The ΣPBDEs in amphipods was higher (on the average 2.5-5-fold) than in sand for almost the totality of congeners detected and each sampling site, suggesting the good capacity of sandhoppers to accumulate these pollutants. Moreover statistical analysis revealed significant differences in PBDE concentrations recorded in tissues of T. saltator among sampling sites. Therefore our results suggested the possible utilization of T. saltator as a biomonitor of PBDE contamination of the supralittoral zone of Mediterranean sandy shores.     

Air concentrations of polybrominated diphenyl ethers (PBDEs) in 2002–2004 at a rural site in the Great Lakes

Atmospheric PBDEs were measured on a monthly basis in 2002–2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg m^?3 for Σ₁₄BDE (excluding BDE-209), and 1.8 ± 1.5 pg m^?3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge–Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west–northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period.     

Atmospheric concentrations and phase partitioning of polybrominated diphenyl ethers (PBDEs) in Izmir, Turkey

Atmospheric concentrations of 7 PBDE congeners (BDE-28, -47, -99, -100, -153, -154 and -209) were determined at four sites (i.e. Suburban, Urban 1, Urban 2, Industrial) in Izmir, Turkey and their gas/particle partitioning was investigated. Total PBDE ( summation operator(7)PBDE) concentrations ranged between 11 (Urban 1) and 149pgm(-3) (Industrial) in summer, while in winter, they ranged from 6 (Suburban) to 81pgm(-3) (Industrial). BDE-209 was the dominant congener at all sites, followed by BDE-99 and -47. Investigation of source profiles indicated that the air samples were dominated by congeners of the penta and deca-technical BDE mixtures. The measured PBDE particle fractions were compared to the predictions of the K(OA) (octanol-air partition coefficient)-based equilibrium partitioning model and to the dynamic uptake model developed by others for passive samplers, which was adapted to model gas-particle partitioning in this study. For BDE-28, good agreement was observed between the experimental particle fractions and those predicted by the equilibrium partitioning model. However, this model overestimated the particle fractions of other congeners. The predictions of the dynamic uptake model supported the hypothesis that the unexpectedly high partitioning of BDEs (except BDE-28) to the gas-phase is due to their departure from equilibrium partitioning. When congeners with very large octanol-air partition coefficients (i.e. BDE-100, -99, -154, -153, and -209) are emitted from their sources in the gas-phase, they may remain in that phase for several months before reaching equilibrium with atmospheric particles. This may also have important implications for the transport of atmospheric PBDEs. For example, in addition to particle-bound transport, the gas-phase transport of highly brominated congeners (i.e. BDE-209) may also be important.     

Occurrence, compositional patterns, and possible sources of polybrominated diphenyl ethers in agricultural soil of Shanghai, China

The present study analyzed surface soil collected from agricultural region of Shanghai to determine the occurrence, compositional patterns and possible sources of polybrominated diphenyl ethers (PBDEs). The results showed that 32 PBDEs were detected among 44 target PBDEs. Total PBDE concentrations ranged from 129 to 1245 ng kg⁻¹ with a mean of 429 ng kg⁻¹. BDE209 was the predominant congener in a range of 33.2-796 ng kg⁻¹ with a mean of 254 ng kg⁻¹. Meanwhile, BDE47, BDE49, BDE153, BDE190, and BDE99 have the most abundant with high concentrations and detectable frequencies. PBDE congeners and homologues analysis and principal component analysis (PCA) also revealed that the major source of PBDE in the soil samples was associated with the prevalent use of technical decabromodiphenyl ether (Deca-BDE) and pentabromodiphenyl ether (Penta-BDE). The correlation analysis proved that there was a significant correlation between total organic carbon (TOC) and lower brominated PBDEs, indicating the significant diffuse nature of the sources of these congeners.     

Effect of sewage sludges contaminated with polybrominated diphenylethers on agricultural soils

The fate of polybrominated diphenyl ethers (PBDEs) in sewage sludge after agricultural application was analysed. This study was based on the analysis of sewage sludge and sludge amended soil samples collected during 2005. PBDE concentrations in sewage sludge ranged from 197 to 1185ng/g dry weight (dw), being deca-BDE-209 the predominant congener. PBDE levels in soils ranged between 21 and 690ng/g dw, being BDE-209 also the predominant congener in all soil samples. Sewage-sludge amendment at the research stations increased concentrations of all BDE congeners 1.2- to 45-fold, with the highest increases for BDE-209. Results obtained evidenced the cumulative effect of the sludge application rates. Moreover, high levels found at soils four years after the last sludge application indicate persistence of PBDEs in soils, including deca-BDE-209.     

Polybrominated diphenyl ethers in soils of the modern Yellow River Delta, China: occurrence, distribution and inventory

The Yellow River is the second largest river in China. In this study, the levels of polybrominated diphenyl ethers (PBDEs) in the modern Yellow River Delta (mYRD) were firstly reported. Twenty PBDE congeners in soil/sediment samples from mYRD were measured. The total PBDE concentrations ranged from non-detectable to 18 257 ng kg⁻¹ with a mean value of 836 ng kg⁻¹. BDE-209 was the dominant congener, accounting for ∼86.1-99.5% of the total PBDEs. The congener profiles of PBDEs with higher abundances of BDE-153 and BDE-183 were similar to those in sediment of the Bohai Sea, indicating that they shared similar sources. The concentrations and congener patterns varied among different regions. Higher levels of PBDEs were found in the middle area (MA), and more complicated congener compositions were also observed in the MA, whereas lower levels of PBDEs were found in the modern course (MC) and the old course (OC). Much more PBDEs were detected in the top layer (TL) soil where more congeners were also held compared to lower soil layers, implying that more PBDEs were emitted into this area in recent years/decades. Organic matter controlled the PBDE distribution in the soil. Soil in this area might be a source of BDE209 for the Bohai Sea.     

Brominated flame retardants and organochlorine pollutants in aquatic and terrestrial predatory birds of Belgium: levels, patterns, tissue distribution and condition factors

Liver and muscle samples from 7 species of aquatic and terrestrial predatory birds from Flanders (Belgium) were analysed for polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and organochlorine pesticides (OCPs). PCBs were the predominant compounds in our samples, which showed highest concentrations in the liver of barn owl (Tyto alba) and sparrowhawk (Accipiter nisus) (up to 1000 microg/g lipid weight). PBDEs could be determined in most samples at lower concentrations than PCBs (up to 64 microg/g lipid in sparrowhawk liver). Sparrowhawks had the highest levels of hexachlorobenzene, DDTs and PBDEs. In contrast, kestrels (Falco tinnunculus) had relatively low levels of most measured organochlorines. BDE 47 was the most abundant congener in heron (Ardea cinerea) and grebe (Podiceps cristatus), while BDE 47, 99 and 153 were equally important in the terrestrial species. BDE 183 and BDE 209 were only measured in the terrestrial birds. These results indicate that terrestrial birds may be more exposed to higher brominated BDE congeners than aquatic species.     

Polybrominated diphenyl ethers in surface sediments of the Yangtze River Delta: Levels, distribution and potential hydrodynamic influence

A total of 32 surface sediments collected from the Yangtze River Estuary, Hangzhou Bay and the Qiantang River were analyzed for polybrominated diphenyl ethers (PBDEs). The concentrations of summation operatorPBDEs (sum of 12 PBDE congeners without BDE 209) and BDE 209 varied from n.d. to 0.55 and from 0.16 to 94.6 ng/g, respectively. The spatial variability of summation operatorPBDEs concentrations indicated that waste discharge from the urban areas might been the main source of PBDEs in the Yangtze River Delta. BDE 209 was the predominant congener (approximately 90-100%) detected among the 13 congeners, consistent with the fact that technical deca-BDE mixtures are presently the dominant technical PBDE mixtures used in China. Compared to published data acquired from other locales, PBDE congeners with less than four bromines were more abundant in the present study area. The hydrodynamic conditions may likely be a significant factor in dictating the observed levels and congener distribution patterns of PBDEs.     

Polybrominated diphenyl ethers in South China maternal and fetal blood and breast milk

Twenty-one-paired human fetal and maternal serum and 27 breast milk samples at South China were analyzed for concentrations of polybrominated diphenyl ethers (PBDEs). Seven PBDE congeners (BDE-28, -47, -99, -100, -153, -154, and -183) were quantified using gas chromatography/mass spectrometry (GC/MS). This is the first report to present the residue levels of PBDEs in human samples of China. The concentrations of total PBDEs ranged from 1.5 to 17 ng/g in the samples and were within the range reported in European samples for a similar population, but lower than human tissue levels in North America. BDE-47 and -153 were the dominant PBDE congeners in all samples and accounted for 60% of the total PBDEs. Further research is needed to determine the exposure route of PBDEs and their health effects.     

Congener-specific accumulation and environmental risk assessment of polybrominated diphenyl ethers in diverse Korean sewage sludge types

Industrial, domestic wastewater, and livestock sludge samples were collected from 23 wastewater treatment plants in Korea and analyzed for polybrominated diphenyl ethers (PBDEs). The concentrations of Σ₁₉PBDE ranged from 4.01 to 10,400 ng/g dry weight. The average Σ₁₉PBDE concentrations in industrial, domestic wastewater, and livestock sludge were 1,560?±?3,610, 402?±?148, and 27.6?±?50.4 ng/g dry weight, respectively. The composition of PBDEs differed according to the type of sludge. Among the PBDE congeners, BDE 209 was dominant in all sludge samples. After BDE 209, relatively high levels were found for BDE 28 and 47 from industrial sludge, BDE 47 and 99 from domestic wastewater sludge, and BDE 206, 207, and 208 from livestock sludge. Using hierarchical cluster analysis, sludges were divided into three groups according to PBDE congener composition. A risk assessment of PBDEs in sludge used for soil amendment was carried out. Preliminary results indicated that the potential risk of soil exposed to PBDEs in sludge was relatively low.     

Occurrence of polybrominated diphenyl ethers in soil from the central Loess Plateau, China: role of regional range atmospheric transport

Very few studies were conducted in highland and depositional areas in studying the transport and behavior of polybrominated diphenyl ethers (PBDEs). In this study, surface soils were collected from Huan County to investigate the level, profile, and potential influence of PBDEs via regional range atmospheric transport in the central part of the Loess Plateau (CLP) of China, one of the most extensive areas of loess deposition in the world. PBDEs were ubiquitous and log-normally distributed in soils from the CLP with mean concentrations of 0.91 and 0.54 ng g⁻¹ for ΣPBDEs (sum of PBDE congeners except for BDE-209) and BDE-209, respectively. BDE-209 was predominated congener (43.5%), followed by BDE-47 (15.7%), 99 (10.7%), and 153 (7.5%). Further principal component analysis on congener profiles showed that PBDEs in the CLP originated from similar source(s). Additionally, significant differences in the ratios of BDE-47 to 99 and BDE-153 to 154 were found between soil samples and commercial products, indicating that they have undergone fractionation during the process of regional range atmospheric transport. The deposition of PBDEs in the CLP could be influenced by the sources from surrounding regions. For example, Xi’an may have potential influence to the CLP based on geographical analysis and concentrations comparison of PBDEs in gaseous. Therefore, more studies are needed to clarify the atmospheric transport and fate of PBDEs in this region.     

Potential role of fire retardant-treated polyurethane foam as a source of brominated diphenyl ethers to the US environment

Five tetra- to hexabrominated diphenyl ether (BDE) congeners (BDE-47, -99, -100, -153 and -154) are the most frequently reported in wildlife and humans. The commercial penta-BDE product, used predominantly to flame-retard polyurethane foam, consists primarily of these same congeners. In 1999, North American demand accounted for 98% of the total global penta-market of 8500 metric tons. Frogs, housed with flame retardant-treated polyurethane foam as a dry substrate, accumulated 10,100 microg/kg (wet weight) of the above BDEs. Crickets kept therein as food contained 14,400 microg/kg. The crickets are believed to have browsed directly on the foam and, in turn, were consumed by the frogs. BDE congener composition in all three matrices matched that of the penta-commercial product. Similar congeners were also observed in soil and stream sediments collected near a polyurethane foam manufacturing plant. Summed concentrations of BDE-47, -99 and -100, the dominant congeners observed in these samples, ranged from < 1 to 132 microg/kg (dry weight basis). Sunfish fillets obtained from a nearby, off-site pond contained a total of 624 microg/kg (lipid basis). Sewage treatment plant (STP) sludge exhibited these same congeners at 1370 microg/kg (dry weight). BDE-209, the fully brominated congener predominant in the commercial deca-BDE product, was also present at 1470 microg/kg. While no known polyurethane foam manufacturers discharged to this plant, the distribution pattern of the low brominated congeners in the sludge matched that of the penta-product. After four weeks of exposure to ambient outdoor conditions, the surface of flame-retarded polyurethane foam became brittle and began to disintegrate. Subsequent dispersal of these penta-containing foam fragments may be one mechanism by which these BDEs reach the environment.