| 1. |
- Balmer, Marianne E, et al.
(författare)
-
Occurrence of Methyl Triclosan, a Transformation Product of the Bactericide Triclosan, in Fish from Various Lakes in Switzerland
- 2004
-
Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 38:2, s. 390-5
-
Tidskriftsartikel (refereegranskat)abstract
- The bactericide triclosan and methyl triclosan, an environmental transformation product thereof, have been previously detected in lakes and a river in Switzerland. Both compounds are emitted via wastewater treatment plants (WWTPs), with methyl triclosan probably being formed by biological methylation. Passive sampling with semipermeable membrane devices (SPMDs) showed the presence of methyl triclosan in some lakes, suggesting some potential for bioaccumulation of the compound. In this study, we report the presence of methyl triclosan in fish (white fish, coregonus sp.; roach, rutilus rutilus) from various lakes in Switzerland receiving inputs from WWTPs. Identification of the compound was based on mass spectral (MS) evidence including MS/MS data. The concentrations of methyl triclosan in the fish were up to 35 ng g-1 on a wet weight basis and up to 365 ng g-1 on a lipid basis with concentrations in a relatively narrow range for fish from the same lake (Thunersee, 4-6 ng g-1; Zürichsee, 32-62 ng g-1; Pfäffikersee, 43-56 ng g-1; Greifensee, 165-365 ng g-1, lipid basis). No methyl triclosan (<1 ng g-1, lipid basis) was detected in fish (lake trout, salmo trutta) from a remote lake in Sweden (Häbberstjärnen) and in fish (roach) from a small lake in Switzerland with no input from WWTPs (Hüttnersee, <2-<5 ng g-1, lipid basis). The concentrations of methyl triclosan in fish correlated (r2 = 0.85) with the ratio of population in the watershed to water throughflow of the lakes (P/Q ratio), which is considered to be a measure for the domestic burden from WWTPs to a lake. Passive sampling with SPMDs confirmed the presence of methyl triclosan in lakes and a river (Zürichsee and Greifensee; Limmat) but not in a remote mountain lake (Jörisee) and in Hüttnersee. The bioconcentration factor (BCF) of methyl triclosan estimated from the fish data and SPMD-derived water concentrations was in the order of 1-2.6 × 105 (lipid basis) and thus in the range of other persistent organic pollutants. SPMDs were found to be reliable for monitoring low concentrations of methyl triclosan in surface water. Methyl triclosan appears to be a suitable marker for WWTP-derived lipophilic contaminants in the aquatic environment and fish.
|
|
| 2. |
|
|
| 3. |
- Santos, Olga, et al.
(författare)
-
Modified stainless steel surfaces targeted to reduce fouling - surface characterization
- 2004
-
Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774. ; 64:1, s. 63-79
-
Tidskriftsartikel (refereegranskat)abstract
- The surface properties of several modified stainless steel samples were characterized according to their chemical composition, roughness, topography and wettability. The modifications tested were SiF3+ and MoS22+ ion implantation; diamond-like carbon (DLC) sputtering: DLC. DLC-Si-O and SiOx, plasma enhanced chemical vapor deposition (PECVD); autocatalytic Ni-P-PTFE and silica coating. X-ray photoelectron spectroscopy (XPS) and X-ray microanalysis were applied to determine the surface chemical composition. Atomic force microscopy (AFM) and stylus-type instruments were used for roughness determination, and the surface topography was imaged with AFM and scanning electron microscopy (SEM). The contact angle and surface tension were measured with the Wilhelmy plate method and the sessile drop method. For thick modified layers, only the elements of the coating were detected at the surface, whereas for thin layers the surface composition determined was that of the stainless steel substrate. The roughness of the 2R (cold rolled and annealed in a protective atmosphere) Surfaces was not altered by the modification techniques (except for the Ni-P-PTFE coating), while for the 2B (cold rolled. heat treated, pickled and skinpassed) surfaces an increase in roughness was observed. The silica coating produced surfaces with consistent roughness, independent of which steel substrate was used. DLC sputtering and Ni-P-PTFE coating produced surfaces with the highest roughness. All modified surfaces revealed a similar surface topography with the exception of the Ni-P-PTFE coating, for which the coating masked the underlying steel topography. In terms of wettability, the SiOx-plasmaCVD and NiP-PTFE coating, techniques produced the most hydrophilic and hydrophobic surfaces, respectively. (C) 2003 Elsevier Ltd. All rights reserved.
|
|
