| 141. |
- Plassmann, Merle M., et al.
(author)
-
Laboratory Studies on the Fate of Perfluoroalkyl Carboxylates and Sulfonates during Snowmelt
- 2011
-
In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:16, s. 6872-6878
-
Journal article (peer-reviewed)abstract
- Perfluoroalkyl acids (PFAAs) are anthropogenic chemicals that occur in snow from both remote and source regions. Experiments were conducted to determine how PFAAs are released from a melting snowpack. Different PFAAs eluted from the snowpack at different times, those with short chains eluting early, those with long chains eluting late. The concentrations in the meltwater of PFAAs with medium chain lengths of 6 to 9 perfluorinated carbon atoms first increased and then decreased during the melt period. Such a peak elution had not been previously observed for any other chemicals. The specific snow surface area (SSA) influenced this elution type, with peak concentrations occurring earlier in a snowpack with lower SSA. Model simulations suggested that the snow surface decrease during the melt alone was insufficient to explain the observations. It was ruled out that the calcium concentration affected PFAA sorption to the snow surface in a similar way as sorption to sediments. Adsorption coefficients of PFAAs to the snow surface were estimated by fitting the measured and modeled elution profiles.
|
|
| 142. |
- Reth, Margot, et al.
(author)
-
Water-to-air transfer of perfluorinated carboxylates and sulfonates in a sea spray simulator
- 2011
-
In: Environmental Chemistry. - 1448-2517 .- 1449-8979. ; 8:4, s. 381-388
-
Journal article (peer-reviewed)abstract
- One hypothesis for the origin of perfluorinated alkyl acids, their salts and conjugate bases (here collectively termed PFAAs) in the atmosphere is transfer from the surface ocean by sea spray, the mechanistic explanation being that the surface active properties of PFAAs result in their enrichment on the surface of bursting bubbles. The water-to-air transfer of C(6)-C(14) perfluorocarboxylates (PFCAs) and C(6), C(8) and C(10) perfluorosulfonates (PFSAs) was studied in a laboratory scale sea spray simulator containing tap water spiked with PFCAs and PFSAs. The sequestration of the PFAAs out of bulk water and to the air-water surface was shown to increase exponentially with the length of the perfluorinated alkyl chain. Volatilisation of the PFAAs from an aqueous solution in the absence of spray resulted in less than 1% transfer to the atmosphere during the experiment. In the presence of spray the transfer rate from water to air increased by up to 1360 times. The enhancement was dependent on the PFAA chain length, with the C(6) carboxylate showing an enhancement of a factor of 37, the C(7) carboxylate an enhancement of 320, whereas for all remaining PFAAs the enhancement exceeded 450 with the exception of the C(14) carboxylate (106).
|
|
| 143. |
- Ribbenstedt, Anton, 1986-, et al.
(author)
-
In Vivo Bioconcentration of 10 Anionic Surfactants in Rainbow Trout Explained by In Vitro Data on Partitioning and S9 Clearance
- 2022
-
In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:10, s. 6305-6314
-
Journal article (peer-reviewed)abstract
- Bioconcentration factors (BCFs) in rainbow trout were measured for 10 anionic surfactants with a range of alkyl chain lengths and different polar head groups. The BCFs ranged from 0.04 L kg–1 ww (for C10SO3) to 1370 L kg–1 ww (C16SO3). There was a strong correlation between the log BCF and log membrane lipid–water distribution ratio (DMLW, r2 = 0.96), and biotransformation was identified as the dominant elimination mechanism. The strong positive influence of DMLW on BCF was attributed to two phenomena: (i) increased partitioning from water into the epithelial membrane of the gill, leading to more rapid diffusion across this barrier and more rapid uptake, and (ii) increased sequestration of the surfactant body burden into membranes and other body tissues, resulting in lower freely dissolved concentrations available for biotransformation. Estimated whole-body in vivo biotransformation rate constants kB-BCF are within a factor three of rate constants estimated from S9 in vitro assays for six of the eight test chemicals for which kB-BCF could be determined. A model-based assessment indicated that the hepatic clearance rate of freely dissolved chemicals was similar for the studied surfactants. The dataset will be useful for evaluation of in silico and in vitro methods to assess bioaccumulation.
|
|
| 144. |
- Ricklund, N., 1979-, et al.
(author)
-
Bioaccumulation of decabromodiphenyl ethane (dbdpe) in the Western Scheldt estuary
-
Other publication (other academic/artistic)abstract
- Decabromodiphenyl ethane (dbdpe) is a brominated flame retardant (BFR) with both a similar chemical structure and similar technical applications to a chemical of recognized environmental concern, decabromodiphenyl ether (decaBDE). Bioaccumulation has been one of the most controversial issues in the risk assessment of decaBDE, but it has not been measured for dbdpe. During the last several years, dbdpe has been detected in a variety of biota, which suggests that it is bioavailable. In this work, dbdpe was analyzed together with decaBDE in a benthic and pelagic food web in the Western Scheldt estuary, an environment known to be contaminated with the two BFRs. The biota-sediment accumulation factors for benthic invertebrates were low (0.0008-0.005) for both chemicals. This weak bioaccumulation into the lowest trophic levels of the food web may have been due to a poor bioavailability of the BFRs into the estuary. Both chemicals were transferred up through the food web, but biodilution was observed, not biomagnification (BMFs 0.2-0.8). The bioaccumulation behavior of dbdpe was similar to that of decaBDE.
|
|
| 145. |
- Ricklund, Niklas, 1979-, et al.
(author)
-
Levels and potential sources of decabromodiphenyl ethane (dbdpe) and decabromodiphenyl ether (decaBDE) in lake sediment and marine sediment in Sweden
- 2010
-
In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 44:6, s. 1987-1991
-
Journal article (peer-reviewed)abstract
- Decabromodiphenyl ethane (dbdpe) is a brominated flame retardant (BFR) used as a replacement for the structurally similar decabromodiphenyl ether (decaBDE), which is a regulated environmental contaminant of concern. Dbdpe has been found in indoor dust, sewage sludge, sediment and biota, but little is known about its occurrence and distribution in the environment. In this paper, sediment was analyzed from 11 isolated Swedish lakes and along a transect running from central Stockholm through the Stockholm archipelago to the open Baltic Sea. Dbdpe was present in all samples. In lake sediment, the levels ranged from 0.23 to 11 ng/g d.wt. and were very similar to the levels of decaBDE (0.48-11 ng/g d.wt.). Since the lakes have no known point sources of BFRs, their presence in the sediments provides evidence for long range atmospheric transport and deposition. In the marine sediment, the dbdpe and decaBDE levels decreased by a factor of 20-50 over 40 km from the inner harbor to the outer archipelago. There the dbdpe and decaBDE levels were similar to the levels in nearby isolated lakes. The results indicate that contamination of the Swedish environment with dbdpe has already approached that of decaBDE, and that this contamination is primarily occurring via the atmosphere.
|
|
| 146. |
- Ricklund, N., et al.
(author)
-
Mass balance of decabromodiphenyl ethane and decabromodiphenyl ether in a WWTP.
- 2009
-
In: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 74:3, s. 389-94
-
Journal article (peer-reviewed)abstract
- The additive flame retardant decabromodiphenyl ethane (deBDethane) has been identified in the environment, but little is known about its environmental behaviour. It is structurally similar to decabromodiphenyl ether (decaBDE), making it conceivable that it may also become an environmental contaminant of concern. In this study a mass balance of deBDethane and decaBDE was undertaken in a modern WWTP in Stockholm serving 7.05x10(5) inhabitants. Flow proportional samples of plant influent and effluent as well as daily grab samples of digested sludge were collected during two 7-day periods. All samples were analyzed with GC/HRMS using isotope labelled internal standards. The mean mass flows of deBDethane and decaBDE to the WWTP were 6.0 g per day and 55 g per day, respectively. Of this, less than 1% of both BFRs left the WWTP via the effluent, while the bulk was sequestered into the digested sludge, where the mean concentrations of deBDethane and decaBDE were 81 and 800 ng g(-1)d.wt., respectively. It is concluded that the transfer efficiency of deBDethane from the technosphere to the environment via WWTPs is similar to that of decaBDE.
|
|
| 147. |
- Sellström, Ulla, et al.
(author)
-
Identifying source regions for the atmospheric input of PCDD/Fs to the Baltic Sea
- 2009
-
In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:10, s. 1730-1736
-
Journal article (other academic/artistic)abstract
- PCDD/F contamination of the Baltic Sea has resulted in the European Union imposing restrictions on the marketing of several fish species. Atmospheric deposition is the major source of PCDD/Fs to the Baltic Sea, and hence there is a need to identify the source regions of the PCDD/Fs in ambient air over the Baltic Sea. A novel monitoring strategy was employed to address this question. During the winter of 2006-2007 air samples were collected in Aspvreten (southern Sweden) and Pallas (northern Finland). Short sampling times (24 h) were employed and only samples with stable air mass back trajectories were selected for analysis of the 2,3,7,8-substituted PCDD/F congeners. The range in the PCDD/F concentrations from 40 samples collected at Aspvreten was a factor of almost 50 (range 0.6-29 fg TEQ/m(3)). When the samples were grouped according to air mass origin into seven compass sectors, the variability was much lower (typically less than a factor of 3). This indicates that air mass origin was the primary source of the variability. The contribution of each sector to the PCDD/F contamination over the Baltic Sea during the winter half year of 2006/2007 was calculated from the average PCDD/F concentration for each sector and the frequency with which the air over the Baltic Sea came from that sector. Air masses originating from the south-southwest, south-southeast and east segments contributed 65% of the PCDDs and 75% of the PCDFs. Strong correlations were obtained between the concentrations of most of the PCDD/F congeners and the concentration of soot. These correlations can be used to predict the PCDD/F concentrations during the winter half year from inexpensive soot measurements.
|
|
| 148. |
- Sobek, Anna, et al.
(author)
-
A comparison of PCB bioaccumulation factors between an arctic and a temperate marine food web
- 2010
-
In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 408:13, s. 2753-2760
-
Journal article (peer-reviewed)abstract
- To test how environmental conditions in the Arctic and the resulting ecological adaptations affect accumulation of persistent organic pollutants (POPs) in the marine food web, bioaccumulation of four polychlorinated biphenyls (PCBs) in an arctic (Barents Sea 77°N - 82°N) and a temperate marine (Baltic Sea 54°N - 62°N) food web were compared. Three different trophic levels were studied (zooplankton, fish, seal), representing the span from first-level consumer to top predator. Previously published high-quality data on PCB water concentrations in the two areas were used for calculation of bioaccumulation factors (BAF). The BAFArctic : BAF Temperate ratios were above 1 for all four PCB congeners in zooplankton (6.4-13.8) and planktivorous fish (2.9-5.0), whereas the ratios were below 1 in seal. The mean ratio between arctic and temperate BAFs for all trophic levels and congeners (BAFArctic : BAFTemperate) was 4.8. When the data were corrected for the seawater temperature difference between the two ecosystems, the ratio was 2.0. We thus conclude that ecological or physiological adaptations of organisms and systems to arctic conditions do at most marginally affect bioaccumulation. Lower seawater temperature lead to a marked thermodynamically favoured passive partitioning to organic matrices and thus elevated ambient BAFs in the Arctic compared with the Baltic Sea. This implies that bioaccumulation in the Arctic may be described in the same way as bioaccumulation in temperate regions, e.g. by the use of mechanistic models parameterised for the Arctic.
|
|
| 149. |
|
|
| 150. |
- Tian, Run, 1994-, et al.
(author)
-
Increasing the Environmental Relevance of Biodegradation Testing by Focusing on Initial Biodegradation Kinetics and Employing Low-Level Spiking
- 2023
-
In: Environmental Science and Technology Letters. - : American Chemical Society (ACS). - 2328-8930. ; 10:1, s. 40-45
-
Journal article (peer-reviewed)abstract
- The environmental relevance of standard biodegradation tests such as OECD 309 has been questioned. Challenges include the interpretation of changing degradation kinetics over the 60–90 incubation days and the effects of chemical spiking on the microbial community. To ameliorate these weaknesses, we evaluated a modified OECD 309 test using water and sediment from three Swedish rivers. For each river, we had three treatments (no spiking, 0.5 μg L–1 spiking, and 5 μg L–1 spiking). The dissipation of a mixture of 56–80 spiked chemicals was followed over 14 days. Changes in dissipation kinetics during the incubation were interpreted as a departure of the microbial community from its initial (natural) state. The biodegradation kinetics were first-order throughout the incubation in the no spiking and 0.5 μg L–1 spiking treatments for almost all chemicals, but for the 5 μg L–1 treatment, more chemicals showed changes in kinetics. The rate constants in the no spiking and 0.5 μg L–1 treatments agreed within a factor of 2 for 35 of 37 cases. We conclude that the environmental relevance of OECD 309 is improved by considering only the initial biodegradation phase and that it is not compromised by spiking multiple chemicals at 0.5 μg L–1.
|
|
