Showing papers by "Swiss Federal Institute of Aquatic Science and Technology published in 1993"
TL;DR: High concentrations of the compounds investigated have been found to occur in macrophytic algae, particularly Cladophora glomerata, and similar concentrations to those in the fish were determined in different tissues of a wild duck.
374 citations
TL;DR: Partition coefficients of octylphenol (OP), nonylphenol(NP), OP and NPnEO (NPnEO, n = 1-3) were determined for n-octanolwater and n-hexanewater systems.
277 citations
TL;DR: In this article, the authors used magnetic low field susceptibility to reconstruct the cyclic changes of Pleistocene palaeoclimates, although the origin of the signal is still poorly understood.
221 citations
TL;DR: Microorganisms can metabolize many aliphatic and aromatic organic contaminants, either to obtain carbon and/or energy for growth, or as co-substrates, thus converting them to products such as carbon dioxide, water, chloride and biomass.
207 citations
TL;DR: In this paper, a simulation of the redox cycle of dissolved iron compounds in atmospheric waters, and the related in-cloud transformations of photooxidants, using γ-radiation to produce HO2/O2−, is presented.
195 citations
TL;DR: Zinc was shown to be required for optimal growth as well as toxin production in Microcystis aeruginosa strains, in agreement with the hypothesis that production of microcystins may be a response to specific environmental stress conditions.
173 citations
TL;DR: In this paper, a mathematical model was developed to describe the dynamic behavior of the anaerobic mesophilic digestion, with special emphasis given to the acetate degradation kinetics.
159 citations
TL;DR: For the extension of the radiocarbon calibration curve beyond 10000 14C y BP, laminated sediment from Lake Soppensee (central Switzerland) was dated using accelerator mass spectrometry (AMS) as mentioned in this paper.
Abstract: For the extension of the radiocarbon calibration curve beyond 10000 14C y BP, laminated sediment from Lake Soppensee (central Switzerland) was dated. The radiocarbon time scale was obtained using accelerator mass spectrometry (AMS) dating of terrestrial macrofossils selected from the Soppensee sediment. Because of an unlaminated sediment section during the Younger Dryas (10000–11000 14C y BP), the absolute time scale, based on counting annual layers (varves), had to be corrected for missing varves. The Soppensee radiocarbon-verve chronology covers the time period from 6000 to 12000 14C y BP on the radiocarbon time scale and 7000 to 13000 calendar y BP on the absolute time scale. The good agreement with the tree ring curve in the interval from 7000 to 11450 cal y BP (cal y indicates calendar year) proves the annual character of the laminations. The ash layer of the Vasset/Killian Tephra (Massif Central, France) is dated at 8230±140 14C y BP and 9407±44 cal y BP. The boundaries of the Younger Dryas biozone are placed at 10986±69 cal y BP (Younger Dryas/Preboreal) and 1212±86 cal y BP (Allerod/Younger Dryas) on the absolute time scale. The absolute age of the Laacher See Tephra layer, dated with the radiocarbon method at 10 800 to 11200 14C y BP, is estimated at 12350 ± 135 cal y BP. The oldest radiocarbon age of 14190±120 14C y BP was obtained on macrofossils of pioneer vegetation which were found in the lowermost part of the sediment profile. For the late Glacial, the offset between the radiocarbon (10000–12000 14C y BP) and the absolute time scale (11400–13000 cal y BP) in the Soppensee chronology is not greater than 1000 years, which differs from the trend of the U/Th-radiocarbon curve derived from corals.
159 citations
TL;DR: In this paper, the aqueous solubilities of nonylphenol, octylphenol and their ethylene oxide adducts with 1-5 ethoxy groups were determined using a generator column technique followed by subsequent off-line HPLC analysis.
156 citations
TL;DR: In this article, an automobile motor exhaust gas from a non-catalyst engine, operated under stationary conditions with unleaded gasoline, was sampled with two different impinger bath methods and analyzed by gas chromatography/mass spectrometry for phenol, cresols and nitrated phenols.
Abstract: Motor exhaust gas from an automobile motor, operated under stationary conditions with unleaded gasoline, was sampled with two different impinger bath methods. The samples were analyzed by gas chromatography/mass spectrometry (GC/MS) for phenol, cresols and nitrated phenols. Phenol and cresols were measured in the range of 80–220 nmol/L of exhaust gas from a noncatalyst engine, and nitrated phenols were found in the range of 9–36 nmol/L. A large reduction of total phenols down to 7% and less was observed when the engine was operated with a regulated three-way catalytic converter. The result of this study shows that exhaust gas sampling of phenols with alkaline aqueous impinger solutions leads to an underestimation of phenol emissions, since phenols are not stable under high-pH conditions.
144 citations
TL;DR: In this article, a continuous flow-through sand reactor was used to study qualitatively and quantitatively the biogeochemical processes resulting from an input of an easily degradable organic substance (lactate) into a model aquifer.
TL;DR: Important biochemical effects of TBT in fish liver are indicated, and exposure to TBT may alter both cytochrome P450 dependent metabolism, and induction response to other environmental pollutants are suggested.
TL;DR: The data presented indicate that the extent of reduction of steady-state residual substrate concentration is dependent on the proportions of the substrates in the mixture, the nature of substrates mixed and the regulation pattern of enzymes involved in their breakdown.
Abstract: Several investigations have shown that during growth in carbon-limited chemostats the simultaneous utilisation of carbon substrates which usually provoke diauxie under batch conditions, i.e., ‘mixed substrate growth’, is probably the rule under ecologically relevant growth conditions. In contrast, the models presently available for the description of the kinetics of microbial growth are all based on the use of single substrates. Systematic studies in chemostat culture have shown that steady-state residual concentrations of individual compounds were consistently lower during mixed substrate growth than during growth with the single substrates. This effect is clearly demonstrated for the case ofEscherichia coli growing with mixtures of glucose plus galactose. The data presented indicate that the extent of reduction of steady-state residual substrate concentration is dependent on the proportions of the substrates in the mixture, the nature of substrates mixed and the regulation pattern of enzymes involved in their breakdown. If this behaviour can be shown to be typical for growth under environmental conditions, it may provide an explanation why microbes still grow relatively fast at the low substrate concentrations encountered in nature.
TL;DR: The results suggest that the reduction of 4-Cl-NB by the enrichment material was a surface-mediated reaction by dissimilatory formed Fe(II) associated with magnetite.
Abstract: 4-chloronitrobenzene (4-Cl-NB) was rapidly reduced to 4-chloroaniline with half-lives of minutes in a dissimilatory Fe(III)-reducing enrichment culture. The initial pseudo-first-order rate constants at 25 degrees C ranged from 0.11 to 0.19 per minute. The linear Arrhenius correlation in a temperature range of 6 to 85 degrees C and the unchanged reactivity after pasteurization indicated that the nitroreduction occurred abiotically. A fine-grained black solid which was identified as poorly crystalline magnetite (Fe(3)O(4)) by X-ray diffraction accumulated in the enrichments. Magnetite produced by the Fe(III)-reducing bacterium Geobacter metallireducens GS-15 and synthetic magnetite also reduced 4-Cl-NB. These results suggest that the reduction of 4-Cl-NB by the enrichment material was a surface-mediated reaction by dissimilatory formed Fe(II) associated with magnetite.
TL;DR: In this article, the authors addressed the design and operation of urban drainage systems in the context of the urban water system comprising drainage, sewage treatment plants and receiving waters, with reference to planning objectives, design objectives, flows and pollutant loads, sewer system structures and urban runoff control and treatment.
01 Jan 1993
TL;DR: This chapter will specifically deal with the physiological changes that take place during the transition phase from unlimited exponential growth to the early starvation phase.
Abstract: One of the most striking features of microbes is their ability to rapidly grow in the presence of abundant nutrients in both the natural and laboratory environments. It is therefore not surprising that a large amount of microbiological research has focused on this phenomenon. Although this book is concerned with starvation in bacteria, it is important that those events which occur during the antithesis of starvation, i.e., during bacterial growth prior to the stationary phase, are also examined. It is well known that the composition and physiology of a bacterial cell are a function of its growth rate and environment (Herbert, 1961; Harder and Dijkhuizen, 1983; Bremer and Dennis, 1987). Consequently, the response to starvation will depend on the conditions under which the cell was growing prior to the onset of exhaustion of a particular essential nutrient. Whereas other chapters in this book have emphasized the important genetic and physiological changes that occur after the onset of starvation and compare these events with those found during unlimited growth, this chapter will specifically deal with the physiological changes that take place during the transition phase from unlimited exponential growth to the early starvation phase.
TL;DR: It is shown that NADH-dependent salicylate monooxygenase activity catalyzed the conversions of salicylic acid and 2,3-dihydroxybenzoic acid to catechol and pyrogallol, respectively and the cyclization products are not substrates to the meta-cleavage product hydrolase activity.
Abstract: Cells of Pseudomonas sp. strain HBP1 grown on 2-hydroxy- or 2,2'-dihydroxybiphenyl contain NADH-dependent monooxygenase activity that hydroxylates 2,2'-dihydroxybiphenyl. The product of this reaction was identified as 2,2',3-trihydroxybiphenyl by 1H nuclear magnetic resonance and mass spectrometry. Furthermore, the monooxygenase activity also hydroxylates 2,2',3-trihydroxybiphenyl at the C-3' position, yielding 2,2',3,3'-tetrahydroxybiphenyl as a product. An estradiol ring cleavage dioxygenase activity that acts on both 2,2',3-tri- and 2,2',3,3'-tetrahydroxybiphenyl was partially purified. Both substrates yielded yellow meta-cleavage compounds that were identified as 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienoic acid and 2-hydroxy-6-(2,3-dihydroxyphenyl)-6-oxo-2,4-hexadienoic acid, respectively, by gas chromatography-mass spectrometry analysis of their respective trimethylsilyl derivatives. The meta-cleavage products were not stable in aqueous incubation mixtures but gave rise to their cyclization products, 3-(chroman-4-on-2-yl)pyruvate and 3-(8-hydroxychroman-4-on-2-yl)pyruvate, respectively. In contrast to the meta-cleavage compounds, which were turned over to salicylic acid and 2,3-dihydroxybenzoic acid, the cyclization products are not substrates to the meta-cleavage product hydrolase activity. NADH-dependent salicylate monooxygenase activity catalyzed the conversions of salicylic acid and 2,3-dihydroxybenzoic acid to catechol and pyrogallol, respectively. The partially purified estradiol ring cleavage dioxygenase activity that acted on the hydroxybiphenyls also produced 2-hydroxymuconic semialdehyde and 2-hydroxymuconic acid from catechol and pyrogallol, respectively.
TL;DR: In this article, a flux balance has been established to determine and to quantify the removal processes in the epilimnion and hypolimnetion of Lake Sempach.
TL;DR: In this paper, the authors investigated the effect of intermittent flushing on the water and pollutant transport through the unsaturated media to be of a highly dynamic nature and found that when applying relatively large hydraulic loads and coarse filter grains, especially in the range above 1 mm, buried filters tend to larger breakthroughs of unoxidized matter due to short retention times and instantaneous lack of oxygen.
TL;DR: In this paper, the authors combine the Weibull wind-speed distribution with commonly employed trilinear and power-law expressions for the dependence of the gas transfer velocity on wind speed to obtain the mean value of the transfer velocity.
Abstract: The analytical representation of wind-speed probabilities by the Weibull distribution allows the empirical characterization of a scalar wind field on the basis of two Weibull parameters. Such a parameterization obviates the necessity of including wind data in time-series form explicitly in air-water interaction models when accounting for non-linear wind effects. By combining the Weibull wind-speed distribution with commonly employed trilinear and power-law expressions for the dependence of the gas transfer velocity on wind speed, analytical expressions for the mean value of the transfer velocity are obtained. These expressions predict the non-linearity of the dependence of gas transfer velocity on wind speed to be responsible for an increase in the mean transfer velocity which will normally not exceed 100% of the value obtained when non-linear wind effects are neglected. In the specific case of the winter oxygenation of a typical subalpine Swiss lake (Aegerisee), the commonly employed trilinear and power-law expressions are found to underestimate the mean O 2 transfer velocity considerably. It is evident that such expressions cannot be employed to determine gas transfer velocities in sheltered lakes without considerable modification at low wind speeds. The extent of the modification required, however, suggests that the role played by the instantaneous wind speed in determining the gas transfer velocity in such lakes may be much less significant than is usually assumed. DOI: 10.1034/j.1600-0889.1993.t01-2-00005.x
TL;DR: Kinetic investigations on cultures of micro-organisms are eminently suited for establishing relationships be-tween growth and environmental factors, especially the nature and amount of nutrients.
Abstract: Growth is the expression par excellence of the dynamic nature of living organisms. Among the general methodsavailable for the scientific investigation of dynamic phenomena, the most useful ones are those that deal withkinetic aspects.Kinetic investigations on cultures of micro-organisms are eminently suited for establishing relationships be-tween growth and environmental factors, especially the nature and amount of nutrients. C. B. van Niel (1949)The study of the growth of bacterial cultures does not constitute a specialised subject of branch of research: it is thebasic method of Microbiology. Monod (1949)
TL;DR: In this paper, a mass balance of a full scale construction waste sorting plant yielded the following results: the separation produced an organic fraction (25%), which is best treated in a municipal solid waste (MSW) incinerator, a metal fraction (3%), well suited for iron recycling, and two inorganic fractions (45 and 27% respectively) of a composition similar to the average earth crust.
01 Jun 1993
TL;DR: In this article, the catalytic decay of O2− radicals due to Cu+ and Cu2+ ions in O2 saturated solutions of low ionic strength was studied by pulse radiolysis and computer simulation of the entire reaction mechanism.
Abstract: The catalytic decay of O2− radicals due to Cu+ and Cu2+ ions in O2 saturated solutions of low ionic strength was studied by pulse radiolysis and computer simulation of the entire reaction mechanism. Phosphate was used as buffer and formate was used to convert OH radicals into O2−. At pH ≈ 6, the very low solubility products of Cu2+ with OH− and PO43- limited the copper concentration to the order of μM. In experiments with [Cu2+] > [O2−], the rate constant k (Cu2++O2−) = (8.0±0.5)·109 M−1 s−1 was determined. In systems with [O2−]>[Cu]tot, steady state for the copper ions is attained with apparent first-order kinetics, which correlates k (Cu2++O2−) with k (Cu++O2−). The O2− decay rate decreased with increasing pH due to Cu2+ complexation with HPO42-. Correspondingly the pK(CuHPO4) was found to be -4.0±0.2 under the assumption that k (CuHPO4+O2−)≤0.01·k (Cu2++O2−. With this value, k (Cu++O2−) could be determined as (9.4±0.8)·109 M−1 s−1 by an iterative procedure. The consequences for the chemistry of atmospheric waters are discussed.
TL;DR: A simple modification of the model accounts well for the effects of ice cover as mentioned in this paper, which predicts that, all else being equal, the oxygen regimes of eutrophic lakes will tend to be affected more by ice cover than those of oligotrophic lakes.
Abstract: A one-box exponential model with constant coefficients is capable of giving a good description of the winter oxygen uptake of a lake not subject to freezing over A simple modification of the model accounts well for the effects of ice cover The modified model predicts that, all else being equal, the oxygen regimes of eutrophic lakes will tend to be affected more by ice cover than those of oligotrophic lakes; that a short period of ice cover is of no great consequence for the oxygen regime of the lake, whereas a long period of ice cover results in a disproportionately large decrease in the mean lake oxygen concentration; and that the later break-up occurs, the greater will be the effect of the ice cover on the oxygen regime of the lake
TL;DR: Aerosol photoemission (APE) has been found to be an excellent surrogate measure of particulate PAH concentration in combustion aerosols under a variety of laboratory and field conditions.
Abstract: Aerosol photoemission (APE) has been found to be an excellent surrogate measure of particulate PAH concentration in combustion aerosols under a variety of laboratory and field conditions. Samples of oil stove, automobile exhaust, and urban air particulate matter were concurrently analyzed for aerosol photoemission intensity and particulate PAH concentration. In-situ, real-time analysis of the particulate matter was performed by UV-induced electron photoemission. Two photon energies, 4.9 and 6.7 eV, were chosen for irradiation. The latter energy was more sensitive and less selective. Particulate PAH concentrations were determined by collecting the particulate matter on a filter, solvent extracting the filter, and analyses of the extracts by gas chromatography / mass spectroscopy. Linear correlations (0.84≤r2≤1.00) were observed between aerosol photoemission intensities and the sum of particulate PAH concentrations for laboratory and field studies under a wide variety of conditions. The studies performed to date cover a dynamic range of three orders of magnitude (1 to 1000 ng / m3). The time resolution is in the order of a few seconds.
TL;DR: The results indicate that metal-induced CaM activation is primarily mediated in the case of cadmium and zinc by resulting calcium/CaM complexes and in the cases of lead by lead/ CaM complexes.
Abstract: The potential of cadmium, zinc, and lead to interact with calmodulin (CaM) was investigated by examiningin vitro CaM-dependent protein phosphorylation in tissues from rainbow trout (Oncorhynchus mykiss) and sea mussel (Mytilus sp.) and CaM-dependent phosphodiesterase (PDE) activation by algal (Chlamydomonas reinhardtii) extracts. Cadmium, zinc, and lead proved effective in sustaining CaM-dependent protein phosphorylation in systems containing calcium, whereas only lead was capable of CaM activation in systems depleted of calcium. Cadmium lead to a small activation of CaM-dependent PDE activity by algal extracts, corresponding to ∼25% of that induced by calcium. Cadmium-induced PDE-activation could be attributed to the residual calcium present in the extract. The results indicate that metal-induced CaM activation is primarily mediated in the case of cadmium and zinc by resulting calcium/CaM complexes and in the case of lead by lead/CaM complexes.
TL;DR: The dynamics of the Ceratium hirundinella population and the abundance of dinocysts in the plankton and sediments were studied in Lake Sempach in 1988 and the rate of survival of theCeratium cysts appears to be lower than that of Peridinium Cysts, which have an impact on the ecosystem as carriers of nutrients.
Abstract: The dynamics of theCeratium hirundinella population and the abundance of dinocysts in the plankton and sediments were studied in Lake Sempach in 1988. In 1987, a rich population ofCeratium (380 cells ml−1) accompanied byPeridinium spp. developed in the lake. The dinocysts were found entrapped in a kind of flocs, in the deepest part of the lake, in the upper flocculent layer. The number of viable cysts ofCeratium in the sediments decreased gradually from April to July 1988. TheCeratium population increased slowly starting in April, and reached a maximum number in August (31 cells ml−1).Peridinium willei reached 100 cells ml−1. Newly formed cysts ofCeratium were recorded in the plankton and sediments at the end of July — beginning of August. They appear in the sediments as separate cells. Their number increased gradually, reaching a maximum of 600 cysts l−1 at the end of October.Ceratium formed more cysts than didPeridinium, but the rate of survival of theCeratium cysts appears to be lower than that ofPeridinium cysts. In addition to their biological functions, the cysts also have an impact on the ecosystem as carriers of nutrients from down to up and from up to down.
TL;DR: Pre-ozonation has been shown to have an adverse effect on physical removal of organic matter at ozone doses above about 0.7 mg O3/mg TOC, while enhanced removal may occur if relatively high concentrations of volatile organic matter are present as discussed by the authors.
TL;DR: In this article, the effect of flocculants on paniculate and dissolved organics removal in wastewater treatment is illustrated when Fe-salts are dosed to raw sewage, to the biological stage or to tertiary filters.
TL;DR: In this paper, the authors show that the FST hemispheres have about the same limitations as has a conventional (i.e. propeller-type) anemometer.
Abstract: SUMMARY
1
FST hemispheres have been proposed as a method for assessing flow characteristics near the river bottom. We suspected that the hemispheres were too big for this goai and that the ground plate would significantly affect near-bottom microhydraulics.
2
The results we present have confirmed our assumption about the limitations of this method: the correlation between FST results and current velocity (measured by an anemometer, φ= 1.2cm) was best at 40% of depth (‘mean current velocity’, coefficient of determination r2= 0,58) and decreased to r2= 0.24 at 0.6 cm above the bottom; the correlation with (calculated) shear stress was only r2= 0.23. A correlation between FST results and macroinvertebrate abundance was found for only four of eight investigated taxa and was similar to the correlation between abundance and ‘mean current velocity’.
3
We conclude that for fieldwork the FST hemispheres have about the same limitations as has a conventional (i.e. propeller-type) anemometer. With the hemispheres we could not obtain better data than with other methods.