| 1. |
- Cornelissen, Gerard, et al.
(författare)
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Freely dissolved PCDD/F concentrations in the Frierfjord, Norway : comparing equilibrium passive sampling with ""active"" water sampling
- 2010
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Ingår i: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1439-0108 .- 1614-7480. ; 10:2, s. 162-171
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Tidskriftsartikel (refereegranskat)abstract
- Equilibrium passive samplers consisting of 55-A mu m polyoxymethylene (POM) and 170-A mu m polydimethylsiloxane were tested for the analysis of polychlorinated dibenzodioxin/furan (PCDD/F) in the pore water and overlying water of the Frierfjord, a bay in southern Norway. This fjord is heavily polluted with PCDD/Fs due to emissions from a former Mg smelter. Field exposures of both equilibrium passive sampler types yielded similar results for freely dissolved PCDD/F concentrations (C (W,free)) in the overlying water. In addition, the passive sampling data deviated less than an order of magnitude from C (W,free) obtained with conventional ""active"" sampling through pumping/filtration over glass fiber filters and polyurethane foam. A similar comparison was done for the pore water, where POM passive samplers also proved to yield freely dissolved pore water concentrations (C (PW,free)) that deviated less than an order of magnitude from earlier published values measured by direct pore water extraction. The data were also used to derive sediment-water activity ratios, which indicate the diffusive flux direction. High sediment-to-water activity ratios (median value of 160 for 17 congeners) indicated a strong diffusion gradient between the sediment pore water and the overlying water, probably due to deposition of particle-bound PCDD/Fs in combination with low sedimentation rates.
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| 2. |
- Magnér, Jörgen, 1971-
(författare)
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Methodologies to assess the fate of polar organic compounds in aquatic environments
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polar organic compounds (POCs) are chemicals with polar functional groups in their structure. The functional groups make the compounds hydrophilic and less prone to partition with biota. However, the knowledge of their fate is limited due to difficulties associated with their measurements. Although, the persistence of POCs in the environment is generally low, they are considered to be semi-persistent compounds due to their continuous introduction to the environment via wastewater. Studies have shown that complex mixtures of POCs of different classes may have synergistic toxic effects on biota at environmental concentration levels. Therefore, it is important to develop analytical methods in order to establish the occurrence and fate of POCs in aquatic environments. In Study I, a positive correlation between the sorption of a novel poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVAC) material and the theoretical logarithmic dissociation partition coefficient (Log D) for seven POCs was observed. The PEVAC material showed an enhanced sorption of the POCs compared to the silicone material. Study II, demonstrated that the PEVAC sampler assess the freely dissolved concentration of POCs in aquatic environments. The results showed that the PEVAC polymer is an attractive alternative to silicone for mimicing the biological uptake of POCs in aquatic environments. Additionally, Study II showed that total extraction is appropriate for determination of the freely dissolved concentration of uncharged POCs with Log KOW < 2.67 in natural water. In study III, a novel bag-solid phase extraction (bag-SPE) technique was compared to a conventional SPE-technique. Despite that the extraction efficiencies for POCs in wastewater were lower using the bag-SPE method, the two methods showed similar detection limits due to the lower ion-suppression experienced with the bag-SPE. In study IV the bag-SPE method was further developed with the aim of lowering the detection limits for POCs. Detection limits (LOD) below 13 ng/L showed that the bag-SPE method was suitable for determination of POCs in surface sea water.
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| 3. |
- Reth, Margot, et al.
(författare)
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Water-to-air transfer of perfluorinated carboxylates and sulfonates in a sea spray simulator
- 2011
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Ingår i: Environmental Chemistry. - 1448-2517 .- 1449-8979. ; 8:4, s. 381-388
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Tidskriftsartikel (refereegranskat)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).
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