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241.
New flavors have been detected in GC/MS chromatograms of surface and sewage waters and fish analyzed for nitro musk compounds. This article names the polycyclic musk flavors 1,3,4,6,7,8-hexahydro-4, 6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyrane (HHCB, known for instance under the trade names: Galaxolide® and Abbalide®), 7-acetyl-1,1,3,4,4,6-hexamethyltetralin (AHTN, known for instance under the trade names: Tonalide® and Fixolide®) and 4-Acetyl-1,1-dimethyl-6-tert.butylindane (ADBI, known for instance under the trade names: Celestolide® and Crysolide®). These substances, which are widely used in the cosmetics and flavor industries, here have been established for the first time in the aquatic environment. HHCB, AHTN and ADBI — as relatively non-polar lipophilic chemicals — like organochlorine pesticides and PCBs after extraction and consecutive purification by gel permeation and silicagel adsorption chromatography are accessible to analysis by gas chromatography/mass spectrometry. Mass spectra show typical mass fragments which allow an unambigous identification and quantification. First results for surface and sewage waters and fish underline the persistence and a relatively high bioconcentration potential of these substances and suggest their ubiqitious distribution in the aquatic environment.  相似文献   
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The toxicities of seleno-L-methionine, seleno-DL-methionine, and selenized yeast were compared. Ten pairs of mallards were fed a control diet and 15 pairs were fed diets containing 10 ppm selenium as seleno-DL-methionine, seleno-L-methionine, or selenized yeast. Hatching of fertile eggs was significantly lower for females fed 10 ppm selenium as seleno-DL-methionine (7.6%) and seleno-L-methionine (6.4%) than for controls (41.3%). Survival of ducklings was lower when their parents had been fed 10 ppm selenium as seleno-L-methionine (20.0%) than for controls (98.4%). The number of 6-day-old ducklings produced per female was significantly lower for mallards fed 10 ppm selenium as seleno-DL-methionine (0.47) or selenized yeast (2.67) than for controls (6.10), and was significantly lower for mallards fed seleno-L-methionine (0.13) than for mallards fed selenized yeast. The eighth eggs of females fed the DL or L forms of selenomethionine contained means of 9.2 and 8.9 ppm selenium, wet weight; these means were higher than the mean (6.6 ppm) for females fed selenized yeast. Among embryos that died at 7 days of age or older, the percentage of embryos that were deformed was 1.3% for controls, 24.6% for seleno-DL-methionine, 28.2% for seleno-L-methionine, and 11.0% for selenized yeast. The results suggested that seleno-DL-methionine and seleno-L-methionine were of similar toxicity and were both more toxic than selenium from selenized yeast.  相似文献   
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Betrieblicher Umweltschutz gilt heute als unverzichtbarer Bestandteil moderner Unternehmensführung. Im Gegensatz zu „end of pipe”-Technologien als kostentreibende Ma?nahmen wird der integrierte Umweltschutz, von der Technologie über das Managementsystem bis hin zum Mitarbeiter zunehmend zu einem betriebswirtschaftlichen Erfolgsfaktor. Notwendige Voraussetzung für diesen Erfolg ist ein gut strukturiertes Umweltmanagementsystem (UM-System). Das beschriebene UM-System orientiert sich an der EG-Verordnung über die „Freiwillige Beteiligung gewerblicher Unternehmen an einem Gemeinschaftssystem für das Umweltmanagement und die Umweltbetriebsprüfung”. Da sowohl auf nationaler als auch auf internationaler Ebene sehr intensiv an einer Normierung von Umweltmanagementsystemen gearbeitet wird, bringt diese Arbeit einen Vergleich zum ISO-Entwurf für UM-Systeme.  相似文献   
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Volatile iodinated organic compounds play an important role in the tropospheric photochemical system, but the current knowledge of the known sources and sinks of these alkyl iodides is still incomplete. This paper describes a new source of alkyl iodides from the pedosphere. Different organic-rich soils and humic acid were investigated for their release of volatile organoiodides. Six volatile organoiodides, iodomethane, iodoethane, 1-iodopropane, 2-iodopropane, 1-iodobutane and 2-iodobutane were identified and their release rates were determined. We assume an abiotic reaction mechanism induced by the oxidation of organic matter by iron(III). The influence of iron(III), iodide and pH on the formation of alkyl iodides was investigated. Additionally, different organic substances regarded as monomeric constituents of humus were examined for the production of alkyl iodides. Two possible reaction pathways for the chemical formation of alkyl iodides are discussed. As humic acids and iron(III) are widespread in the terrestrial environment, and the concentration of iodide in soil is strongly enriched (compared to seawater), this soil source of naturally occurring organoiodides is suggested to contribute significantly to the input of iodine into the troposphere.  相似文献   
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An aquatic microcosm study was designed to evaluate the direct and indirect effects of a 14 day, 100 μg atrazine/L exposure on periphyton community functional and structural parameters and to determine the recovery rates of these parameters after removing the atrazine input. Direct and indirect effects were evidenced by an immediate and continual decrease in net productivity and by significantly reduced algal densities, decreased diversity, altered species composition and reduced biomass accumulation. There were substantial differences in community recovery rates with net productivity returning to control values within 16 days while little recovery in community structural parameters occurred within the 21-day time period examined.  相似文献   
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ABSTRACT: Artificial aeration is used to prevent winter fish kills due to oxygen depletion in ice-covered lakes. Conventional aeration by air bubble plumes and other techniques usually mixes the water column and produces hazardous open water in the ice cover. A non-mixing winter lake aeration system which creates a fish refuge was designed and field tested to oxygenate the water and maintain water temperature stratification in a lake such that no open water is created. The system uses a cascade aerator and has a design discharge and dissolved oxygen input rate of 85 1/s and 70 kg/d, respectively. Aerated water is discharged near mid-depth with minimum disturbance of the ambient water through a specially designed diffuser. The system was tested in a shallow 3 m deep lake of 17 ha surface area during two winters and was found to perform as expected. Significant photosynthetic production of dissolved oxygen under the ice-cover was also observed during snow-free periods.  相似文献   
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