Trends in hexabromocyclododecanes in the UK and North America.

Water samples (n = 107) taken from nine English freshwater lakes from a mix of urban, rural, and remote locations on 12 occasions between August 2008 and February 2012, and archived suspended sediment samples (n = 39) collected over the period 1980-2012 at the mouth of the Niagara River in Lake Ontario were analysed to assess the temporal trends in contamination by the three main hexabromocyclododecane (HBCD) diastereomers (α-, ß-, and γ-HBCD). HBCDs (45 to 890 pg L-1, n = 107) were generally equally distributed between the operationally defined freely dissolved and particulate phases in English lake water. Concentrations of HBCDs declined over the sampling period with half-lives of 5.1 years in English water, with a significantly decreasing trend also observed for Niagara River suspended sediments (NRSSs). With respect to seasonal trends, significantly higher concentrations were found in colder compared to warmer periods at 5 out of 9 English lakes, while NRSSs in this study revealed no statistically significant seasonal trends. The maximum HBCD concentration in NRSSs was about 3 orders of magnitude lower than those detected in English lake water, which is plausible given the greater per capita use of HBCD in Europe than North America. While γ-HBCD was consistently dominant (35-86%; mean = 56%) in English lake water samples, and dominated in NRSSs collected prior to 2002 inclusive (13-100%, mean = 73%), the abundance of γ-HBCD was significantly lower (3.5-37%; mean = 23%) in NRSSs from 2003 onwards.

Polybrominated diphenyl ethers (PBDEs) in English freshwater lakes, 2008-2012.

Concentrations of tri-to-hexa-BDEs were determined in water samples taken from 9 English lakes on 13 occasions between April 2008 and February 2012. Across all sites, concentrations of ΣBDEs in individual samples ranged from 9.2 to 171.5pgL(-)(1), with an average of 61.9pgL(-)(1). Notwithstanding the far greater use of the Penta-BDE commercial formulation in the USA, concentrations in this study are comparable to the limited data available for the Great Lakes. PBDE concentrations showed no evidence of a decline at any monitored location over the study period. This may be because this study commenced 4years after the introduction of restrictions on the Penta- and Octa-BDE formulations. While concentrations normalised to water volume at the different locations were statistically indistinguishable; significant spatial variation was apparent when the data were normalised to total suspended solids (TSS) content. However, this spatial variation was not correlated with factors such as population density and lake catchment area, suggesting that concentrations of PBDEs in lake water in this study are a complex integral of numerous factors. BDE-47:99 ratios and concentrations of ΣBDEs respectively decreased and increased significantly with increasing TSS content. As TSS content was elevated in colder compared with warmer periods, such seasonal variation in TSS content appears a major contributor to the observed elevation of ΣBDE concentrations in colder periods, and higher BDE-47:99 ratios in warmer periods.

Photolysis of brominated flame retardants in textiles exposed to natural sunlight.

Photolytic transformation profiles of technical hexabromocyclododecane (HBCD) and technical decabromodiphenyl ether (DecaBDE) in flame-retarded textiles exposed to natural sunlight were compared. Textiles that contained approximately 4% HBCDs by weight showed no substantial loss of any of the HBCD diastereomers during the entire exposure period (371 days), indicating that they were resistant to sunlight, that is, that debromination and isomerization of HBCD diastereomers did not occur under the experimental conditions. Exposure of a textile treated with technical DecaBDE resulted in the formation of polybrominated dibenzofurans (PBDFs) as products of photodecomposition of polybrominated diphenyl ethers present in the technical DecaBDE. After 329 days of exposure, the total PBDF concentration reached a maximum of 27 000 ng g(-1), which was approximately 10 times the initial concentration. During the experiment, di- to hexa-BDF congener concentrations increased continuously. Although the concentrations of PBDFs in the textiles were 4­5 orders of magnitude lower than the concentrations of polybrominated diphenyl ethers, it is important to note that PBDFs were formed as a result of sunlight exposure during normal use of products treated with technical DecaBDE.

Chiral signatures show volatilization from soil contributes to polychlorinated biphenyls in grass.

Enantiomer fractions (EFs) of PCB 95 and concentrations of PCBs 28/31, 52, 101, 118, 138, 153, and 180 were determined in air. Samples were taken at ~14 day intervals on a vertical gradient at an urban background site in Birmingham U.K. in summer 2009 (114 days) and spring 2010 (84 days). EFs in air at 3 cm height were nonracemic (average 0.453 (2009) and 0.468 (2010)) and differed significantly (p < 0.05) from the racemic EFs in air at 10, 40, 90, and 130 cm. EFs in soil (average 0.452 (2009) and 0.447 (2010)) closely matched those in air at 3 cm, while those in grass (average 0.468 (2009) and 0.484 (2010)) were intermediate between those in soil and the racemic EFs in air at ≥ 10 cm. This implies that at the study site, PCBs volatilize from soil to an extent discernible only at the soil:air interface, and that PCBs in grass arise due to foliar uptake of volatile emissions from soil. Atmospheric concentrations of ΣPCBs increased significantly (p < 0.05) with increasing height. Combined with the chiral signature data, this suggests the influence of PCB emissions from soil on airborne concentrations decreases with altitude, while that of emissions from the built environment increases.

Dust from U.K. primary school classrooms and daycare centers: the significance of dust as a pathway of exposure of young U.K. children to brominated flame retardants and polychlorinated biphenyls.

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol-A (TBBP-A), and polychlorinated biphenyls (PCBs) were measured in floor dust from U.K. child daycare center and primary school classrooms (n = 43, 36 for PCBs). Concentrations of HBCDs exceeded significantly (p < 0.05) those reported previously for U.K. houses and offices, while those of TBBP-A exceeded significantly those in U.K. cars and offices. PCB concentrations were statistically indistinguishable from those in U.K. house dust but lower than in U.S. classroom dust, while BDEs 47, 99, 100, 153, 196, 197, 203, and 209 in classrooms were significantly below concentrations in U.K. cars. Exposure of young U.K. children via classroom dust exceeds that of U.K. adults via office dust for all contaminants monitored. Overall dust exposure of young U.K. children was estimated including car, classroom, and house dust. Exposure to TBBP-A was well below a U.K. health-based limit value (HBLV). Though no HBLVs exist for non-dioxin-like PCBs and HBCDs; dust exposure to PCBs fell well below U.K. dietary and inhalation exposure. Contrastingly, a high-end estimate of HBCD dust exposure exceeded U.K. dietary exposure substantially. Moreover, high-end estimates of dust exposure to BDE-99 and BDE-209 (4.3 and 13000 ng/kg bw/day, respectively) exceeded HBLVs of 0.23-0.30 and 7000 ng/kg bw/day respectively.