Showing papers by "Swiss Federal Institute of Aquatic Science and Technology published in 1988"

The Chemistry of Ozone in Water

Abstract: From lists of published rate constants for the direct reactions of aqueous ozone with substrates we can conclude: if, for example, 0.5 mg/l ozone is present, the following types of compounds react within less than 10 seconds: sulfite, nitrite, olefinic aliphatic hydrocarbons, phenols, polyaromatic hydrocarbons, organic amines and sulfides. Much slower to react are some chlorosubstituted olefins (chlorinated solvents). Benzene, saturated hydrocarbons, or tetrachloroethylene require days to be significantly oxidized by molecular ozone.

Factors controlling the biogeochemical cycles of trace elements in fresh and coastal marine waters as revealed by artificial radioisotopes

Abstract: Radionuclides in aquatic ecosystems can provide important insights into the way physical, chemical, biological, and sedimentological processes are coupled into networks to control the transfer of major and trace elements within the waterbody itselfand across its boundaries. Examples from artificial radionuclide studies in freshwater (Experimental Lakes Area in Northern Ontario, ELA) and coastal marine ecosystem enclosures (MERL tanks at Narragansett Bay, Rhode Island) show the cycling of selected trace elements across the sediment-water interface as these are influenced by various biogeochemical factors. The approach to meaningful studies using radiotracers should include the separate characterization of the physical transport processes, and preferably a comparison of the fate of radiotracers to those of stable elements in the same system, to allow for kinetic studies of chemical forms. The kinetics of transformation of different chemical species of Co, Hg, Ag, Se, and Cr ions, under variable pH (ELA) or redox (MERL) conditions appeared to be indirectly linked to the kinetics of organic carbon cycling. A better knowledge of the predominant chemical species of trace elements present in these systems will be important in understanding bioavailability, biomagnification, and toxicity of trace elements in aquatic ecosystems.

Purification and characterization of a bacterial nitrophenol oxygenase which converts ortho-nitrophenol to catechol and nitrite.

Abstract: A nitrophenol oxygenase which stoichiometrically converted ortho-nitrophenol (ONP) to catechol and nitrite was isolated from Pseudomonas putida B2 and purified. The substrate specificity of the enzyme was broad and included several halogen- and alkyl-substituted ONPs. The oxygenase consisted of a single polypeptide chain with a molecular weight of 58,000 (determined by gel filtration) or 65,000 (determined on a sodium dodecyl sulfate-polyacrylamide gel). The enzymatic reaction was NADPH dependent, and one molecule of oxygen was consumed per molecule of ONP converted. Enzymatic activity was stimulated by magnesium or manganese ions, whereas the addition of flavin adenine dinucleotide, flavin mononucleotide, or reducing agents had no effect. The apparent Kms for ONP and NADPH were 8 and 140 microM, respectively. 2,4-Dinitrophenol competitively (Ki = 0.5 microM) inhibited ONP turnover. The optimal pH for enzyme stability and activity was in the range of 7.5 to 8.0. At 40 degrees C, the enzyme was totally inactivated within 2 min; however, in the presence of 1 mM ONP, 40% of the activity was recovered, even after 10 min. Enzymatic activity was best preserved at -20 degrees C in the presence of 50% glycerol.

Tritium hydrologic studies in four closed‐basin lakes in the Great Basin, U.S.A.1

Abstract: Four closed-basin lakes in the Great Basin (Lake Abert, Oregon; Mono Lake, California; Pyramid Lake and Walker Lake, Nevada) were analyzed for tritium (3H) in water samples collected in 1969, 1976, 1980, and 1981. In each case the tritium concentration increased to a maximum in the mid-to late 1960s in response to fallout produced by nuclear weapons testing and then slowly decreased soon after the 1966 moratorium. The highest level attained was a function of the water residence time of the lake (i.e. shorter residence time corresponding to higher maximum tritium concentration), and the rate of decrease was slowest for lakes with longer water residence times. The residence time of tritium is less than the water residence time and depends strongly on the evaporative exchange of tritium with the atmosphere. A tritium hydrologic model was constructed in an attempt to constrain hydrologic properties such as evaporation rate, relative humidity, and the degree of homogeneity of the water column with respect to tritium. If evaporation rates determined from hydrologic balance are within 20% of the true rates, then the tritium input must be between 50 and 90% enriched over that calculated from data on tritium fallout in Portland rain. This enrichment is considerably reduced if the surface waters are on the average depleted by about 10% in tritium relative to the whole lake. Calculated mean relative humidities lie between 0.45 (Mono Lake) and 0.25 (Walker Lake). Calculated exchange velocities in the gas phase are between 17 and 27 m h−1, which corresponds to a mean wind speed of about 4 m s−1.

Uranium in pore waters from North Atlantic (GME and Southern Nares Abyssal Plain) sediments

Abstract: A central question to be addressed by the international sub-seabed radioactive waste disposal program is the mobility of radionu-clides through sediments, which are the most important barrier to the transfer to the ocean and eventually to man. The major component of high-level radioactive waste is uranium. Here we report the measurement of low uranium concentrations in composite pore-water samples from the uppermost 20–30 m of deep-sea abyssal plain sediments from the Great Meteor East and Southern Nares Abyssal Plains Area. Many values are between 0.1 and 0.5 p.p.b. (parts per 109) which are the lowest uranium concentrations ever measured in the pore waters of deep-sea sediments. Our lowest value, 0.05±0.01 p.p.b., is orders of magnitude lower than the predicted solubility of UO2 or U4O9, probably indicating solubility control of U(IV) by an adsorbed phase. The uranium concentrations obtained from both sites correlate closely with measured redox potentials (Eh) in the sediments. The low mobility of uranium in pore waters from turbiditic deep-sea abyssal plain sediments, which can be deduced from these measurements, has important implications for the sub-seabed disposal of high-level radioactive waste, and for marine geochemistry of uranium.

Diagenetic Processes in Aquatic Mine Tailings Deposits in British Columbia

Abstract: Mine wastes have been deposited in coastal or terrestrial aquatic systems for at least two millenia, historically without regard for the biological, chemical or physical consequences of such disposal. The rise of industrialization and coincident exponential growth in the rates of metal consumption and exploitation have been associated with a profound increase in the annual volume of mine tailings requiring permanent storage on the earth’s surface. A parallel consequence has been the steady shift towards exploitation of lower grade, larger volume orebodies which has radically increased the volume of tailings produced by most contemporary milling operations. This phenomenon has increased the need to find or construct large-volume repositories for tailings storage near mine sites; when coupled with the growing awareness of the serious long-term environmental risks posed by terrestrial disposal, and typical attractive economics, submerged storage in both fresh and saline waters is becoming an increasingly appealing alternative.

Residues of detergent-derived organic pollutants and polychlorinated biphenyls in sludge-amended soil

Abstract: Concentrations des biphenyles polychlores et des agents de surface: alkyl benzene sulfonates et nonylphenol polyethoxylates dans le sol et dans les boues d'epandage

Isolation of cobamides from Methanothrix soehngenii: 5-methylbenzimidazole as the α-ligand of the predominant cobamide

Abstract: Methanothrix soehngenii was found to contain five different cobamides when grown on vitamin B12 supplemented as well as vitamin B12 free media. In both cases, it was shown by HPLC-chromatography and UV/VIS spectroscopy, that α-5-methylbenzimidazolyl-β-cyanocobamide was the predominant cobamide, accounting for 27% and 23%, respectively, of the total corrinoid content. Vitamin B12 and α-5-hydroxybenzimidazolyl-β-cyanocobamide could also be detected in both cell batches in varying amounts. Cells grown on vitamin B12 free medium contained significantly more baseless cobamides, indicating biosynthesis of cobamides.

Quelques aspects de l'alimentation de deux poissons planctonophages du Lac Léman: le corégone ( Coregonus schinzii palea Cuv. et Val.) et le gardon ( Rutilus rutilus (L.))

Abstract: Dans le but de comparer leur alimentation, des coregones et des gardons ont ete captures a l'aide de chaluts pelagiques (gardons seulement), de filets maillants pelagiques et de fond dans le lac Leman entre decembre 1983 et juillet 1985. En zone pelagique, les deux especes sont bien des planctonophages stricts. Ils y partagent les memes ressources trophiques entre juin et octobre. Les proies principales ingerees sont alors Daphnia sp. puis surtout Leptodora kindtii et Bythotrephes longimanus. Il est montre qu'il n'est pas possible de conclure a une competition alimentaire entre ces deux especes de poissons faute de donnees suffisantes sur la biologie de leurs proies.

The drift of zooplankton in a lake-outlet (Glatt) in a day-night-rhythm depending from the water level

Abstract: To give an indication on the influence of the dynamics and behavior of lake plankton on the seston composition in the outlet, four 24-hour sampling sessions were made in the Greifensee (situated near Zurich, Switzerland) and its outlet (River Glatt). The most important crustacean species studied wereEudiaptomus gracilis, Cyclops abyssorum, Cyclops vicinus, Mesocyclops leuckarti andDaphnia spp.Leptodora kindtii was found during one sampling only. No evidence of shore avoidance was found. The vertical migration in the lake especially in the upper layer (0–6 m) is believed to have an influence on the amount of plankton which is flushed into the outlet. Although the composition and concentration of the plankton at the deepest point of the lake have been known, no accurate predictions on the quality of the plankton close to shore or in the outlet were possible.

Mass Fluxes of Linear Alkylbenzenesulphonates, Nonylphenol, Nonylphenol Mono- and Diethoxylate Through a Sewage Treatment Plant

Abstract: Dissolved and particulate LAS, NP, N1PEO and NP2EO were determined in raw sewage, primary effluent, secondary effluent, primary and secondary sludge of the sewage treatment plant Zurich-Glatt on two consecutive sampling days. The results were combined with sewage flow rate and dry matter load measurements in order to obtain the respective mass fluxes. The latter provided information on the major removal processes affecting these detergent derived chemicals, i. e. biodegradation during the activated sludge treatment and incorporation into sludge. The overall removals of LAS over the two sampling days were 99.3% and 98.7% (w/w), of which 13% and 16%, respectively, were found in raw sludge and 9% and 13%, respectively, in anaerobically digested sludge. Both NP1EO and NP2EO were poorly removed in the secondary effluent and were educts for NP in sludge. Nonylphenol loads in the anaerobically digested sludge were 4.7 and 6.4 times larger than in the raw sewage.

Behaviour and Modelling of NTA Degradation in Activated Sludge Systems

Abstract: The general model for single-sludge wastewater treatment systems of the IAWPRC task group (Henze et al., 1987) was extended to describe the biological degradation of NTA and adsorption of NTA onto activated sludge based on literature studies and experiments undertaken at the Glatt wastewater treatment plant (waste water discharge: Q = 55 − 60 000 m3/d, 110 000 inhabitants) for the city of Zurich. During two days, the behaviour and diurnal load variation of nitrilotriacetate (NTA), zinc, lead and copper were analyzed on one lane (volume = 1 812 m3, Q = 14 700 m3/d) of the four parallel lanes used in secondary treatment. The plant had a sludge age of about 3.6 days and was partly nitrifying (wastewater temperature = 10-11 °C). The average daily load of NTA for the investigated lane was 14 kg NTA/d, corresponding to 0.5 g NTA/person d. The influent concentration varied between 300 and 1 500 μg NTA/l. NTA was biologically degraded up to 97 %. Between 12 am and 2 pm of the second day 17 kg NTA (120 % of the daily load of one lane) had been added to the primary effluent. During 4 to 5 hours the biological NTA degradation was saturated and four times more than the daily average of NTA was degraded. Zinc and lead did increase in the secondary effluent during the NTA shock loading.

The Sandoz/Rhine Accident

Abstract: On 1 November 1986 a fire at a Sandoz warehouse resulted in a massive input of chemicals to the atmosphere, Rhine River and surrounding soils. The wave of chemicals in the river, predominately Disulfoton and Thiometon, was monitored as it traveled to the North Sea. This chemical wave resulted in the death of benthic organisms and fish, especially eels. From the measured and estimated concentrations, Etrimfos, Endosulfan and Formothion were probably the lethal chemicals. The measured water concentrations from the period directly following the accident suggest that some of the chemicals were lost from the main wave before it reached the North Sea. Based on the physical, chemical and biological properties of the pesticides and the hydraulic characteristics of the Rhine, the fate and transport of the chemicals have been modeled. It is predicted that most were quickly flushed from the river. The exceptions are the mercury compounds and possibly Endosulfan. Other than these there should be no residual of the chemicals in the water, sediment or biota.

Modelling of Anthropogenic Substances in Aquatic Systems: MASAS — A Personal Computer Approach

Abstract: Mathematical models for evaluating the dynamic behaviour of anthropogenic substances in aquatic systems (MASAS) are being developed and implemented on a personal computer. The MASAS system will allow the user to construct models of increasing complexity for lakes, rivers, and groundwater aquifers, and to build up compound and system libraries. In this paper, the general concept of the MASAS system is described and a summary of the present status of implementation is given.

Total organic carbon emissions from municipal incinerators

Abstract: Total carbon (TC), carbonate carbon (CC) and total organic carbon (TOC) were determined in bottom ash, filter dust and flue gas of Swiss municipal solid waste (MSW) incinerators. The highest TOC load was found in the bottom ash (2–3 g kg-1 MSW), followed by the filter dust (0.1–1.0 g kg-1 MSW) and the flue gas (0.05–0.3 g kg-1 MSW). The composition and behaviour of the bulk of TOC in these products is not yet known. In order to minimize the risk of leaching organic substances as well as metals due to biological, chemical and physical reactions of the products of incineration in a landfill, it is suggested the incineration process be optimized towards complete combustion.