| 1. |
|
|
| 2. |
|
|
| 3. |
- Larsson, Per, et al.
(författare)
-
Contaminated sediment as a source of PCBs in a river system
- 1990
-
Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 47:4, s. 746-754
-
Tidskriftsartikel (refereegranskat)abstract
- The transport of PCBs (Aroclor 1242) in a river system in southern Sweden was governed by outflow from sediment in a 26-ha contaminated lake. Experiments in the lake revealed that 14 g PCBs/d escaped from the sediment, while sedimentation was 3 g PCB/d. Volatilization of PCBs from the lake surface was 0.02 g/d, which was considerably higher than the atmospheric fallout . The majority of the sediment-desorbed compounds (80%) remained at the river mouth, 60 km downstream, and entered the Baltic Sea. Desorption increased the ratio of tetrachlorobiphenyls to pentachlorobiphenyls in the water. Transport across the water/air interface was higher for trichlorobiphenyls, while atmospheric deposition was dominated by penta- and hexachlorobiphenyls. Therefore, the sediment of the lake acted as a source of PCBs entering the river system as well as the atmosphere.
|
|
| 4. |
- Ryding, Mauritz Johan, 1981, et al.
(författare)
-
X-ray induced fragmentation of size-selected salt cluster-ions stored in an ion trap
- 2014
-
Ingår i: RSC Advances. - 2046-2069. ; 4:88, s. 47743-47751
-
Tidskriftsartikel (refereegranskat)abstract
- A method for spectroscopic characterization of free ionic clusters and nanoparticles utilizing X-ray synchrotron radiation is presented. We demonstrate that size-selected ammonium bisulphate cluster ions, NH 4+(NH 4HSO4) n, captured in a linear ion trap, exhibit well-defined core-level absorption edges in the reconstructed fragment-ion abundance spectra. In addition to the specific photo-fragmentation pathways observed at the N1s-, O1s- and S2p-edges, dissociation also occurs as a consequence of clusters colliding with helium present as buffer gas in the ion trap. Separate off-beam experiments were conducted to establish the activation kinetics of these collision induced dissociation processes. Furthermore, it is demonstrated that the electrons released upon photoionization of background helium are too few in number to produce multiply charged cluster ions, and thereby induce fragmentation of the salt clusters, to any significant degree. The mechanisms for photon absorption and subsequent cluster fragmentation are analysed and discussed. In addition to its inherent element specificity, the method holds promise for cluster structure elucidation resulting from the sensitivity of the near edge absorption structure to the local chemical environment of the excited atom.
|
|
