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- Kierkegaard, Amelie, 1955-
(författare)
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PBDEs in the Environment : Time trends, bioaccumulation and the identification of their successor, decabromodiphenyl ethane
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polybrominated diphenyl ethers (PBDEs) are important chemical flame retardants, but also environmental pollutants. Their bromine substitution lends them a different bioaccumulation behaviour than the better studied organochlorines.The contamination of a Swedish lake with lower brominated BDEs was assessed by a retrospective study of pike. The concentrations of tetra- to hexaBDEs increased exponentially up to the mid-1980s and then decreased slowly, possibly reflecting the voluntary reduction in production/usage of the chemicals. Methoxylated PBDEs were found to be present in similar concentrations to the PBDEs, but originated from different sources. The large size of the bromine atom was believed to result in negligible absorption of higher brominated BDEs in wildlife, thus explaining the low levels observed in fish despite high levels in e.g. sediment. However, it was shown that the fully brominated BDE, BDE209, was absorbed to a small extent via the diet. Once absorbed, it was reductively debrominated to lower brominated BDE congeners. Debromination was also observed in dairy cows exposed to higher brominated BDEs in their natural diet. Moreover, the molecular size restricted the transfer of higher brominated BDEs to milk. In contrast to PCBs and lower brominated BDEs, there was no equilibrium between adipose tissues and milk fat, and with increasing bromine substitution a progressively smaller fraction of the ingested PBDEs was transferred to the milk.This thesis highlights differences in uptake, metabolism and excretion for PBDEs compared to the well characterized organochlorines. A knowledge that is useful for risk assessments given the ongoing use of these compounds. Furthermore, a representative of the next generation brominated flame retardants, decabromodiphenyl ethane, a replacement for the BDE209 technical product, was identified for the first time in the environment.
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| 3. |
- Björklund, Justina Awasum, et al.
(författare)
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Perfluoroalkyl compounds (PFCs) in indoor dust : concentrations, human exposure estimates, and sources
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:7, s. 2276-2281
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are globally distributed, persistent, toxic, and are found in human blood and serum. Exposure pathways are not well characterized. To better understand indoor dust ingestion as a potential pathway for human exposure, we determined the concentrations of these compounds in dust collected from 10 houses, 38 apartments, 10 day care centers, 10 offices, and 5 cars. Samples were prepared using a rapid extraction and cleanup method and analyzed using LC-MS/MS. PFOS and PFOA were found in dust samples from all microenvironments and their concentrations were significantly positively correlated to each other. Highest median concentrations were seen in offices (PFOS: 110 ng/g dry weight) and apartments (PFOA: 93 ng/g dw). Adult and toddler dust ingestion exposures were estimated and compared to dietary exposure data from Canada and Spain. Results show that diet is the most important exposure route, but in a worst case scenario, dust ingestion may also be significant.
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| 4. |
- Björklund, Justina Awasum, et al.
(författare)
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PFOS and PFOA in dust from Stockholm microenvironments.
- 2008
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Ingår i: The 28th International Symposium on Halogenated Persistent Organic Pollutants (Dioxin 2008), Birmingham, UK, 18-22 August 2008..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 9. |
- de Wit, Cynthia A.
(författare)
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Nanoteknik – tänk efter före.
- 2008
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Ingår i: MISTRA Nyhetsbrev. ; :5, s. 2-
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Tidskriftsartikel (populärvet., debatt m.m.)
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