Decamethylcyclopentasiloxane (D(5)) is a volatile compound used in personal care products that is released to the atmosphere in large quantities. Although D(5) is currently under consideration for regulation, there have been no field investigations of its atmospheric fate. We employed a recently developed, quality assured method to measure D(5) concentration in ambient air at a rural site in Sweden. The samples were collected with daily resolution between January and June 2009. The D(5) concentration ranged from 0.3 to 9 ng m(-3), which is 1-3 orders of magnitude lower than previous reports. The measured data were compared with D(5) concentrations predicted using an atmospheric circulation model that included both OH radical and D(5) chemistry. The model was parametrized using emissions estimates and physical chemical properties determined in laboratory experiments. There was good agreement between the measured and modeled D(5) concentrations. The results show that D(5) is clearly subject to long-range atmospheric transport, but that it is also effectively removed from the atmosphere via phototransformation. Atmospheric deposition has little influence on the atmospheric fate. The good agreement between the model predictions and the field observations indicates that there is a good understanding of the major factors governing D(5) concentrations in the atmosphere.

Dietary uptake and effects of decabromodiphenyl ether (DeBDE), a widely used flame retardant, were studied in rainbow trout. Fish were fed for 16, 49, or 120 days with control or DeBDE-treated food (7.5−10 mg of DeBDE/kg of body weight/day). One group was fed DeBDE for 49 days and then control diet for 71 days to study depuration. Chemical analyses were performed using GC/MS(ECNI). Several physiological and biochemical variables were also measured. DeBDE concentrations in muscle increased from <0.6 ng/g of fresh weight to 38 (±14) ng/g after 120 days. Corresponding liver concentrations were <5 and 870 (±219) ng/g of fresh weight. Several hexa- to nonabromodiphenyl ethers, present in both liver and muscle, increased in concentration with exposure length. These congeners originate from metabolism of DeBDE and/or selective uptake of minor components in the DeBDE product. After depuration, DeBDE concentrations declined significantly, but concentrations of some lower brominated congeners were unaffected. Liver body index and plasma lactate concentrations were higher in fish exposed for 120 days and in the depuration group, indicating delayed chronic effects, possibly from lower brominated congeners. DeBDE uptake (0.02−0.13%) and possible metabolism seem not to be major sources of tetra- and pentabromodiphenyl ethers found in wild fish.

Fish and sediments from several places along the Swedish River Viskan, sampled in 1995, were analyzed for polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). The samples were collected up‐ and downstream from several possible point sources (textile industries) for these compounds. Tetrabromodiphenyl ethers (TeBDEs), pentabromodiphenyl ethers (PeBDEs), and decabromodiphenyl ether (DeBDE [BDE209]) were found in sediment. Tetrabromodiphenyl ethers and PeBDEs were also found in fish. Hexabromocyclododecane was identified in sediment and fish. Large fish to sediment ratios for TeBDE, PeBDEs, and HBCD indicate that these are highly bioavailable, whereas BDE209 seems not to be as bioavailable. The lowest PBDE and HBCD levels were found upstream of the industries and concentrations generally increased progressively further downstream as more industries were passed. This is in agreement with earlier investigations of PBDEs in fish from the same river. Many brominated compounds are photolabile, which can complicate their analysis. Under the conditions used in this investigation it was observed that BDE209 in a solvent that was subject to the clean‐up procedure partly decomposed to compounds with shorter retention times, whereas BDE209 seemed to be stable in the sample extracts. Another matrix effect could be observed in the increased sensitivity obtained for some of the investigated compounds in fish and sediment extracts as compared to standard solutions. This effect may obscure analytical results obtained with electron capture mass spectrometric detections.

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Guillemot eggs from the Baltic Sea, sampled between 1969 and 2001, were analyzed for tetra- and pentabromodiphenyl ethers (2,2',4,4'-tetraBDE (BDE-47), 2,2',4,4',5-pentaBDE (BDE-99), and 2,2',4,4',6-pentaBDE (BDE-100)), and hexabromocyclododecane (HBCD). This temporal trend study indicates that the concentrations of the polybrominated diphenyl ether compounds increased from the 1970s to the 1980s, peaking around the mid- to the late-1980s. These peaks are then followed by a rapid decrease in concentrations during the rest of the study period, with the concentrations of the major BDE congener below 100 ng/g lipid weight at the end of the period. This corresponds to less than 10% of its peak values. The concentrations of HBCD show a different pattern over time. After a peak in the middle of the 1970s followed by a decrease, the concentrations increased during the latter part of the 1980s. During the recent 10-yr period no significant change has occurred, and the annual mean concentrations are more or less stable at a higher level as compared to the beginning of the study period.

Cyclic volatile methyl siloxanes (cVMS) are present in technical applications and personal care products.They are predicted to undergo long-range atmospheric transport, but measurements of cVMS in remote areas remain scarce. An active air sampling method for decamethylcyclopentasiloxane (D5) was further evaluated to include hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), and dodecamethylcyclohexasiloxane (D6). Air samples were collected at the Zeppelin observatory in the remote Arctic (79°N, 12°E) with an average sampling time of 81 ± 23 hours in late summer (AugustOctober) and 25 ± 10 hours in early winter (November -December) 2011. The average concentrations of D5 and D6 in late summer were 0.73 ± 0.31 ng/m 3 and 0.23 ± 0.17 ng/m 3 respectively, and 2.94 ± 0.46 ng/m 3 and 0.45 ± 0.18 ng/m 3 in early winter respectively. Detection of D5 and D6 in the Arctic atmosphere 2 confirms their long range atmospheric transport. The D5 measurements agreed well with predictions from an Eulerian atmospheric chemistry-transport model, and seasonal variability was explained by the seasonality in the OH radical concentrations. These results extend our understanding of the atmospheric fate of D5 to high latitudes, but question the levels of D3 and D4 that have previously been measured at Zeppelin with passive air samplers. IntroductionCyclic volatile methyl siloxanes (cVMS) are high-volume production chemicals used in the production of silicone polymers, in personal care products, and in a range of technical applications. cVMS have been found in both the physical environment and in biota, and have lately become subject to increasing scientific scrutiny by environmental scientists and regulators. 1-3The three congeners, and dodecamethylcyclohexasiloxane (D6) have specifically been the focus of the attention.e.g.1-3Hexamethylcyclotrisiloxane (D3) is an additional member of the group of cVMS. The physical-chemical properties of cVMS differ from many known organic pollutants, as they combine high volatility with extreme hydrophobicity and a considerable affinity for organic phases like octanol (Table S1). 4Volatilization to the atmosphere is the main emission pathway of cVMS to the environment. 1-3 Hence the atmosphere is a key compartment for understanding the environmental fate and behavior of cVMS. Once in the atmosphere, cVMS are predicted to be mainly present in the gas phase, and degradation by reaction with hydroxyl radicals is understood to be the main removal mechanism. 5 The atmospheric half-lives due to reaction with hydroxyl radicals are 20.0 days for D3, 10.3 days for D4, 6.7 days for D5, and 5.8 days for D6 (Table S1). The estimated levels of D5 from these models correspond well with observed atmospheric concentrations in the environment. 9, 11 The predicted seasonality of D5 was a consequence of the strong seasonality of the hydroxyl radical concentrations at high latitudes. During the polar night low levels of hydroxyl radicals slow down the atmospheric degradation of D5 and allow it to ...

The brominated flame retardant decabromodiphenyl ethane, DeBDethane, is marketed as an alternative to decabromodiphenyl ether, BDE209. There are currently no data available about the presence of DeBDethane in the environment. In this study, DeBDethane was positively identified by high-resolution mass spectrometry and quantified by low-resolution mass spectrometry with electron capture negative ionization in sewage sludge, sediment, and indoor air. It was found in 25 of the 50 Swedish sewage treatment plants investigated, with estimated levels up to about 100 ng/g dry weight. The concentration of DeBDethane in sediment from Western Scheldt in The Netherlands was 24 ng/g dry weight, and in an air sample from a Swedish electronics dismantling facility it was 0.6 ng/m3. DeBDethane was also found together with nonabromodiphenyl ethanes in water piping insulation. All samples contained BDE209 in higher concentrations as compared to DeBDethane (DeBDethane/BDE209 ratios ranging from 0.02 to 0.7), probably reflecting the higher and longer usage of BDE209. There is an ongoing risk assessment within the European Union regarding BDE209. Since DeBDethane has similar applications, it is important to investigate its environmental behavior before using it to replace BDE209.

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