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Showing papers by "Swiss Federal Institute of Aquatic Science and Technology published in 1979"


Journal ArticleDOI
TL;DR: In this paper, perylene was abundant and was the only high molecular weight polycyclic aromatic hydrocarbon present in the Namibian seafloor sediments collected at two sites offshore of southwest Africa.

107 citations


Journal ArticleDOI
TL;DR: In this article, the spontaneous ozone requirement of surface and ground waters (0.1 to 1 mg/l) and the lifetime of the ozone (30 to 2,000 sec at pH 8) can easily be measured.
Abstract: In order to transfer experience from one waterwork to another, it is helpful to know (i) the spontaneous ozone requirement, (ii) the lifetime of the ozone, and (iii) the oxidation efficiency of the secondary oxidants derived from decomposed ozone (OH* radicals) in the different waters. The spontaneous ozone requirement of surface and ground waters (0.1 to 1 mg/l) and the lifetime of the ozone (30 to 2,000 sec at pH 8) can easily be measured. The effect of the secondary oxidants (OH* radicals) can best be characterized by following the elimination rate of the individual suitable referenced micropollutant as a function of the amount of ozone decomposed. This way the “Oxidation-Competition Value”, Ω, of the water can be determined. This Ω is a linear sum of the concentrations of all impurities which consume OH* radicals, multiplied by the individual “Oxidation-Competition Coefficient.” The Ω values have been determined for 40 different types of waters. For the elimination of benzene (reference solut...

98 citations


Journal ArticleDOI
01 Sep 1979
TL;DR: In this article, the chemical speciation of dissolved copper was investigated in waters from the limno-corrals of the MELIMEX project and compared with speciation data from other Swiss lakes.
Abstract: The chemical speciation of dissolved copper was investigated in waters from the limno-corrals of the MELIMEX project and compared with speciation data from other Swiss lakes. Copper is complexed primarily by organic ligands having molecular sizes between 104 and 103 daltons. The mean concentration of the ligands is approximately 5×10−7 mole/mg DOC. The conditional stability constants (pH=8.8) are about 1011. An increased metal load did not induce an increase of binding ligands. A comparison of calculated Cu2+ concentration with corresponding copper contents in the biomass leads to the conclusion that organic ligands and pH are the most important factors in deciding the biological availability of copper. However the sorption capacity of the biomass depends as well on the variety of plankton species.

44 citations


Journal ArticleDOI
01 Sep 1979
TL;DR: In this article, the long-term impacts of increased metal loading on phytoplankton communities of large limno-corrals (diameter 12 m, depth 10 m) were studied.
Abstract: Long-term impacts of increased metal loading (Hg, Cu, Cd, Zn and Pb) on phytoplankton communities of large limno-corrals (diameter 12 m, depth 10 m) were studied. Increased metal concentrations initially lowered phytoplankton biomass, as well as species number and photosynthetic activity of phytoplankton. They caused changes in metal speciation and shifts in phytoplankton community structure, favoring less susceptible species. Although adaptation was not sufficient to completely prevent the metal-induced depression of photosynthesis, due to depressed zooplankton grazing, at the end of the experiment even higher phytoplankton densities were observed in the metal-loaded corrals than in the control.

37 citations


Journal ArticleDOI
01 Sep 1979
TL;DR: A detailed description of the limno-corrals (diameter 12 m, depth 10 m water flow through rate 11.5 m3/day) used in this study is presented as discussed by the authors.
Abstract: It was the goal of the interdisciplinary research project MELIMEX to study ecological consequences of increased heavy metal loadings on limnic ecosystems. A detailed description of the limno-corrals (diameter 12 m, depth 10 m water flow through rate 11.5 m3/day) used in this study is presented. Since the physico-chemical environment must have a direct bearing on the results of such an experiment a brief description of Lake Baldegg, in which the experiments were conducted is given and conditions in which limno-corrals differ from natural systems are discussed. Furthermore the major findings of the various MELIMEX studies are briefly summarized.

33 citations


Journal ArticleDOI
01 Sep 1979
TL;DR: In this article, the results indicate that these metals are not accumulated through the food chain and suggest that increased metal concentrations in the environment favor the growth of phytoplankton organisms with a low metal sorption capacity.
Abstract: Phytoplankton, periphyton and zooplankton samples, chironomid andSialis sp. larvae, and fry of trout and bream collected from unpolluted and artificially metal-polluted limno-corrals were analyzed for mercury, copper, cadmium, zinc and lead. The results indicate that these metals are not accumulated through the food chain and suggest that increased metal concentrations in the environment favor the growth of phytoplankton organisms with a low metal sorption capacity.

30 citations


Book ChapterDOI
01 Jan 1979
TL;DR: In this paper, the authors calculated the amount of decomposed ozone required to achieve a desired degree of elimination of a specified solute by OH. radicals, which is proportional to the sum of the rates with which the total of solutes present in the wastewater consumed by the radicals.
Abstract: Summary Some solutes present in secondary effluents are oxidized by a direct reaction of molecular ozone during an ozonation process. These oxidations are very selective. Their rates can be calculated from the concentration of ozone and the 2nd order reaction rate constants measured for specified solutes in water. Part of the ozone decomposes in water, leading to the formation of secondary oxidants. Of these, the OH. radicals easily oxidize even inert types of organic solutes, but they are non-selective and become consumed by fast reactions. The amount of decomposed ozone required to achieve a desired degree of elimination of a specified solute by OH. radicals is therefore proportional to the sum of the rates with which the sum of solutes present in the wastewater consumes OH. radicals. At elevated pH values, even carbonate ions and free ammonia contribute to this OH. radical consumption. The yield of the oxidations and its dependence on water composition can be estimated from reaction-rate constants.

26 citations


Journal ArticleDOI
01 Sep 1979
TL;DR: In a limno-corral (diameter 12 m, depth to sediments 10 m) located in Baldeggersee (Switzerland), vertical mixing has been measured during more than one year and compared to the conditions in the open lake, the corral has a more shallow epilimnion.
Abstract: In a limno-corral (diameter 12 m, depth to sediments 10 m), located in Baldeggersee (Switzerland), vertical mixing has been measured during more than one year and compared to the conditions in the open lake (maximum depth 65 m, surface area 53 km2) The temperature method by McEwen and Hutchinson yields Kz values between 5×10−2 cm2s−1 at the upper boundary of the thermocline and 2×10−3 cm2s−1 at the bottom, a value near the molecular diffusion of heat at 4°C (136×10−3 cm2s−1) Kz calculated from profiles of excess radon-222 generally agree with those from the temperature data Compared to the open lake, the corral has a more shallow epilimnion However, during calm meteorological conditions, vertical mixing in the upper 10 m is similar outside and inside the corral

21 citations


Journal ArticleDOI
01 Mar 1979
TL;DR: In this primary production phase, the phosphate content of the water decreases within 10 days to 5%, of its original value, while large herbivorous populations reduce the sedimentation rate of the organic substance, while increasing the P:C ratio of the sediment.
Abstract: Size-selective enrichment or exclusion of planktonic crustaceans significantly alters the succession of phytoplankton and smaller zooplankton. The cell density of algae (particularly of smaller forms) and the rate of production (life expectancy) of zooplankton increase sharply in the test units poor in zooplankton. In this primary production phase, the phosphate content of the water decreases within 10 days to 5%, of its original value. Large herbivorous populations reduce the sedimentation rate of the organic substance, while increasing the P:C ratio of the sediment.

19 citations


Book ChapterDOI
01 Jan 1979
TL;DR: In this article, the influence of temperature on the stoichiometry and rate of microbial processes is reviewed and classified into more fundamental processes such as mass transfer, biomass production, biomass decay and substrate uptake.
Abstract: The influence of temperature on the stoichiometry and rate of microbial processes is reviewed. Microbial rate processes are segregated into more fundamental processes such as mass transfer, biomass production, biomass decay and substrate uptake to provide a more systematic basis for analysis. The application of the techniques to determine temperature dependence of several unit processes is demonstrated with case studies based on published data.

19 citations


Journal ArticleDOI
01 Sep 1979
TL;DR: The crustacea plankton of three artificial model lakes in Lake Baldegg was observed during 15 months as mentioned in this paper, and two were loaded continuously with low concentrations of five heavy metals (Hg, Cu, Cd, Zn, Pb).
Abstract: The crustacea plankton of three artificial model lakes in Lake Baldegg was observed during 15 months. Two were loaded continuously with low concentrations of five heavy metals (Hg, Cu, Cd, Zn, Pb).

Book ChapterDOI
01 Jan 1979
TL;DR: In this paper, the primary and pre-precipitation primary treatment in combination with simultaneous precipitation and conventional activated sludge processes have been operated in parallel in semi-technical scale.
Abstract: Conventional and pre-precipitation primary treatment in combination with simultaneous precipitation and conventional activated sludge processes have been operated in parallel in semi-technical scale. Experimental results are evaluated in order to yield design information for alternative chemical-biological wastewater treatment processes for organic carbon removal, nitrification and phosphorus removal. Data regarding nutrient mass flow, sludge production and sludge thickening characteristics, biological kinetics and phosphorus precipitaion is given for an integrated design of primary-secondary processes. Achievable residual concentrations of collective and specific water quality parameters are expressed in statistical terms.

Journal ArticleDOI
01 Sep 1979
TL;DR: In this article, the transport paths of the trace metals Cu, Zn, Cd, Hg and Pb were investigated in three limno-corrals of the MELIMEX project and the reaction of the systems on increased metal loads were investigated.
Abstract: In three limno-corrals of the MELIMEX project the transport paths of the trace metals Cu, Zn, Cd, Hg and Pb and the reaction of the systems on increased metal loads were investigated. The metal balances lead to the conclusion that the biomass is the main factor responsible for the regulation of trace metal concentration. The observed sequence of relative residence times of the trace metals can be described with a steady-state model. Additional metal load decreases the ability of the limnic system to lower the metal concentration. The production of phytoplankton and its assimilation capacity for metals are reduced leading to relatively higher metal concentrations in the lake.

Book ChapterDOI
01 Jan 1979
TL;DR: In this article, the influence of process flow scheme (one to twelve stage CSTR aeration tank), hydraulic residence time, recycle rate and sludge age is discussed in small and large treatment plants with high and low diurnal load variations respectively.
Abstract: Dynamic simulation of the activated sludge process is used to predict nitrification performance. The influence of process flow scheme (one to twelve stage CSTR aeration tank), hydraulic residence time, recycle rate and sludge age is discussed in small and large treatment plants with high and low diurnal load variations respectively. Ammonium load equilibration, recycle flow rate and variation of process configuration between contact stabilization, step feed and plug flow type processes are discussed as process control parameters. Results indicate trends for process preformance and should be applicable for a wide variety of process situations.

Journal ArticleDOI
01 Mar 1979
TL;DR: The occurrence of ciliates in "Aufwuchs" was studied at 439 sampling stations in 194 Swiss streams during the summers of 1974 and 1975 as discussed by the authors, at each station at least two water samples from each station were taken for chemical analysis; parameters measured were: total dissolved phosphate, total phosphate, particulate phosphorus, total nitrogen, Kjeldahl, nitrogen in unfiltered water, nitrate, dissolved organic carbon, calcium; electrical conductivity and water temperature were measured at the site.
Abstract: The occurrence of ciliates in ‘Aufwuchs’ was studied at 439 sampling stations in 194 Swiss streams during the summers of 1974 and 1975. At least two water samples from each station were taken for chemical analysis; parameters measured were: total dissolved phosphate, total phosphate, particulate phosphate, total nitrogen, Kjeldahl, nitrogen in unfiltered water, nitrate, dissolved organic carbon, calcium; electrical conductivity and water temperature were measured at the site.

Book ChapterDOI
01 Jan 1979
TL;DR: In this paper, a statistical analysis for ΣP versus Lp, the annual P-input per unit lake surface, based on 62 lakes from North America and Europe, reveals a tendency for the annual primary production to increase with decreasing mean depth.
Abstract: Physical processes such as the intensity of vertical mixing, influence the annual primary production (ΣP) which is chosen as trophic state index. Measured values of ΣP can be split into two components, a minimum productivity (ΣP0) calculated with a simple epilimnic one-box model, and an “internal productivity” (ΣP1) attributed to internal nutrient supply by vertical mixing. A statistical analysis for ΣP versus Lp, the annual P-input per unit lake surface, based on 62 lakes from North America and Europe, reveals a tendency for ΣP to increase with decreasing mean depth. For Lp>3 g P m-2yr-1, ΣP reaches a saturation value of about 400 gC m-2yr-1, while the influence of ΣP1 disappears due to light limitation. For an intermediate Lp, the large variation of ΣP among individual lakes with the same loading shows the importance of other factors such as morphometry, intensity of vertical mixing (reflecting exposure to wind), and the redox potential at the sediment-water interface. The later controls the redissolution of mineralized nutrients at the sediment surface.

Journal ArticleDOI
01 Sep 1979
TL;DR: The formula is derived from the substance concentration, times the volume of a truncated cone, which gives total content of the lake.
Abstract: Total content is used mostly for balances. In order to calculate the areas of different depths, the contours are cut out of a topographical map and weighed.

Journal ArticleDOI
01 Sep 1979
TL;DR: In this paper, the particle size distributions in three limno-corrals, located in Baldeggersee, Switzerland, have been determined by means of a Zeiss Micro-Videomat image analyzer as a function of depth and time.
Abstract: The particle size distributions in three limno-corrals, located in Baldeggersee, Switzerland, have been determined by means of a Zeiss Micro-Videomat image analyzer as a function of depth and time. The distributions were measured biweekly over a period of 1 year at depths of 0 m, 2.5 m, 5 m, 7.5 m and 10 m (=above bottom). Two of the limno-corrals were charged with heavy metals, whereas the third was uncharged and served as a reference. The shape of the distributions as well as the particle concentrations in the uncharged container did not differ from the ones in the charged limno-corrals. The distributions were found to be self-preserving and independent on heavy metal load, time, depth and particle concentrations. As an average, the dependence of the distributions on the particle diameter was found to be −1.5 to −2.5.

Book ChapterDOI
01 Jan 1979
TL;DR: In this article, the causes of eutrophication of rivers are studied in artificial outdoor rivers, where small amounts of domestic sewage added to groundwater stimulates the growth of algae, whereby each metal most likely has a different effect.
Abstract: The causes of eutrophication of rivers are being studied in artificial outdoor rivers. Small amounts of domestic sewage added to groundwater stimulates the growth of algae. This eutrophying effect cannot be duplicated by the supply of the same quantity of PO4-P and/or NO3-N as is found in the active sewage. The supply of a mixture of the 6 essential heavy metals Fe, Mn, Co, Cu, Mo and Zn on the other hand does affect the growth activity of the algae occurring naturally in the channels, whereby each metal most likely has a different effect. This results, depending on the season and the amount of mixture added, in changes of the sociological composition of the algal benthos and can considerably enhance the biomass accumulation. Due to the characteristic dose response of single algal species to individual metals the role of essential heavy metals in eutrophication is likely to be rather complex.

Journal ArticleDOI
01 Sep 1979
TL;DR: The degree of metal induced inhibition of glucose uptake varied from lake to lake and season to season, whereby the addition of legally tolerated concentrations of 10 μg Cu/l and 200 μg Zn/l inhibited glucose uptake in most samples significantly, as well as the simultaneous addition of all metals as discussed by the authors.
Abstract: Glucose uptake in lake water samples has been determined with short-time14C-experiments at different additions of the single heavy metals Cu++, Zn++, Cd++, Pb++, Hg++ and at different additions of a combination of all metals. The degree of a metal induced inhibition of glucose uptake varied from lake to lake and from season to season, whereby the addition of legally tolerated concentrations of 10 μg Cu/l and 200 μg Zn/l inhibited glucose uptake in most samples significantly, as well as the simultaneous addition of all metals. The legally tolerated limit of 1 μg Hg/l inhibited glucose uptake in Lake Lucerne samples almost completely, showed however no effect in samples of Lake Baldegg.


Journal ArticleDOI
01 Mar 1979
TL;DR: In this paper, liver and muscle tissue from fish from two Swiss lakes, namely the Lake of Biel and the Walensee, were analyzed for the heavy metals Hg, Cd, Cu, Pb and Zn.
Abstract: Liver and muscle tissue from fish caught between 1973 and 1975 in two Swiss lakes, namely the Lake of Biel and the Walensee, were analyzed for the heavy metals Hg, Cd, Cu, Pb and Zn. The research project was carried out within the framework of an international OECD programme. The mean of the heavy metal concentrations in mg/kg undried material lay within the following ranges: Open image in new window The comparison of metal concentrations in fish originating from the two lakes revealed for the Lake of Biel higher Hg values throughout and higher Cu and Zn values in the livers, whereas for the Walensee the Cd values were found to be higher in the livers. The Pb concentrations did not differ significantly. With regard to the examined organs (livers and muscles) the comparison showed higher Hg concentrations in the muscles than in the livers. The Cd, Cu, Pb and Zn concentrations, however, were found to be higher in the livers.