bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strukturchemische Eigenschaften und Spurenstoffverhalten in aquatischen Ökosystemen
Authors: Koch R. 
Published: February 2007

AbstractGrundlage der Modellierung von Stoffverteilungen organischer Stoffe in aquatischen Systemen sind die Verteilungskoeffizienten in n‐Octanol/Wasser, insbesondere im Hinblick auf die Bioakkumulation der Stoffe. Zugleich bestehen gute Korrelationen der Verteilungskoeffizienten zu Molekülparachor und Molrefraktion. Schließlich bestehen gesicherte Beziehungen dieser Parameter zu den für manche Stoffe bekannten Bioakkumulationsfaktoren und toxikologischen Daten, für letztere insbesondere zur Molrefraktion als Ausdruck der Elektronen‐beweglichkeit und damit für die Reaktivität der organischen Substanzen. Im weiteren müssen derartige Ansätze genutzt werden, um sowohl strukturchemische Parameter mit wesentlichen Ausbreitungsparametern in biogeochemischen Kreisläufen zu verknüpfen und die toxische Wirkung auf entsprechende strukturchemische Parameter zurückzuführen.
Beitrag zur quantitativen Analyse geringer Chloridgehalte mittels ionensensitiver Elektrode
Authors: Neupert L. 
Published: February 2007

AbstractIm Zusammenhang mit der Bestimmung des Gruppenparameters „Organisch gebundenes Chlor”︁ ist ein Verfahren zur quantitativen Chloridbestimmung erforderlich, welches auch in niedrigen Konzentrationsbereichen reproduzierbare und richtige Ergebnisse liefert. Unter diesem Aspekt wurde ein potentiometrisches Verfahren, welches auf die Anwendung einer chloridsensitiven Elektrode (Hersteller: VEB Keramische Werke Hermsdorf — DDR) zurückgreift, geprüft.Einzelheiten der Methode sowie theoretische und praktische Aspekte bei ihrer Anwendung werden beschrieben. Eigene Untersuchungsergebnisse werden vorgestellt und nach mathematisch statistischen Gesichtspunkten bewertet.
Zum dünnschichtchromatographischen Nachweis toxikologisch relevanter Stoffgruppen im Trinkwasser
Authors: Lawerenz A. 
Published: February 2007

AbstractChlorierte Kohlenwasserstoffe (ClKW), polycyclische aromatische Kohlenwasserstoffe (PAK) und Verbindungen aus der Gruppe der Alkane und Cycloalkane (KW) lassen sich simultan aus einer Wasserprobe mit Cyclohexan extrahieren und nach der Anreicherung dünnschichtchromatographisch auftrennen und nebeneinander nachweisen.Die Trennung erfolgt auf zwei verschiedenen Sorptionsschichten:

Silufol‐Fertigfolie
Acetylcellulose/Aluminiumoxidmischsorptionsschicht (silbernitratimprägniert).
Beide Trennmethoden ergänzen sich im Hinblick auf die Identifizierung einzelner Verbindungen der Stoffgruppen.Die Nachweisgrenzen der Detektion betragen für PAK 2 … 10 ng, für CIKW 30 … 100 ng und für KW 0,5 … 20 μg.Zur schnellen Analyse von Trinkwässern wird eine Routinemethode vorgeschlagen, die im niedrigen Konzentrationsbereich eine semiquantitative Bestimmung ermöglicht.
Gesichtspunkte zur hygienischen Beurteilung der in der Trinkwasserversorgung angewandten Kunststoffe
Authors: Salacz K. 
Published: February 2007

AbstractAuf dem Gebiet der Trinkwasserversorgung werden in zunehmendem Maße Kunststoffe verwendet, aus denen gewisse lösliche Komponente ins Wasser gelangen. Darunter befinden sich Stoffe, die sich im Menschen im Laufe des Lebens kumulieren und teilweise schädlich auswirken. Deshalb muß die Menge der aus den Kunststoffen über das Trinkwasser in den Organismus gelangenden Fremdstoffe gering gehalten werden.Im Interesse der Verminderung dieser Gefahr, hat das Ministerium für Gesundheitswesen der Ungarischen Volksrepublik in einer Verordnung die Genehmigung der Verwendung von Kunststoffen in der Trinkwasserversorgung geregelt.Grundlage dieser Genehmigung bildet die Untersuchung der Wasserextrahierbarkeit des Kunststoffes. Die Untersuchungen werden seitens der Abteilung für Wasserhygiene des Staatlichen Institutes für Hygiene, Budapest, durchgeführt. Im Interesse der sicheren Beurteilung der Kunststoffe (Schutzschichten, Rohrverbindungsprofile usw.) werden die Untersuchungen in verschiedenartigen Wässern bei einem Verhältnis von Oberfläche zu Wassermenge vorgenommen, das das in der Praxis übliche Maß um mehrere hundertmal übertrifft.Bei Rohren bietet diese Methode keine Sicherheit, deshalb wird hier ein Rohrstück mit 11 Rauminhalt zur Untersuchung verwendet.Bei der wasserhygienischen Bewertung werden die neue ungarische Trinkwasserbeschaffenheitsnorm Nr. MSz 450/1–78, die Vorschriften des Bundesgesundheitsamtes der Bundesrepublik Deutschland und die Grenzwerte des Wasserschadstoff‐Katalogs der Deutschen Demokratischen Republik berücksichtigt.Neben der chemischen Untersuchung der bei der Trinkwasseraufbereitung angewandten Polymere wird auch die Durchführung einer toxikologisch‐hygienischen Untersuchung für notwendig gehalten. Die toxikologischen Untersuchungen werden von der Abteilung für Biologie und Toxikologie des Instituts für Hygiene, Budapest, durchgeführt.Nach den Ergebnissen der Untersuchungen und sonstiger in der Verordnung Nr. 3/1971. Eü. M. vorgeschriebener technischer Angaben wurde die Anwendung einiger neuer Kunststoffe auf dem Gebiet der Trinkwasserversorgung vom Ministerium für Gesundheitswesen der UVR genehmigt und ins Stammbuch eingetragen. Das Register dieser Stoffe, bzw. die Stammbuchtexte werden in den Zeitschriften „Vizügyi Értesito”︁ (Mitteilungen vom Wasserwesen) und „Egészségügyi Közlöny”︁ (Anzeiger des Gesundheitswesens) veröffentlicht.
Zur Darstellung und Auswertung wassertoxikologischer Untersuchungsergebnisse am Beispiel der Tenside
Authors: Gottschaldt N. 
Published: February 2007

AbstractFünf anionische und drei kationische Detergentien werden in ihrer Wirkung auf Carassius, Daphnia und Paramecium getestet. Bestimmt wird die „Sterbehalbwertszeit”︁, jene Zeit, in der unter den gewählten Versuchsbedingungen bei der jeweiligen Konzentration des Giftstoffes 50% der Versuchsorganismen sterben. Zwischen der Konzentration D des Giftes und der „Sterbehalbwertszeit”︁ t gilt die Beziehung D = d + a · e−c·t. Für den Parameter c dieser Modellbeziehung wird der Begriff des Toxizitätskoeffizienten vorgeschlagen. Er stellt ein Maß für die Kinetik des Intoxikationsverlaufes dar, während d die Grenzkonzentration toxischer Wirkung im Langzeitversuch und a den Konzentrationsbereich toxischer Wirkung darstellen. Für alle untersuchten Substanzen besteht ein eindeutiger Zusammenhang zwischen Toxizität und Erniedrigung der Oberflächenspannung.
Population Dynamics, Biomass and Biomass Production of Eudiaptomus gracilis (G. O. SARS) in Two Water Areas of Differing Trophic State of Lake Balaton (Hungary)
Authors: Ponyi J. E. , Zánkai N. P. 
Published: February 2007

AbstractPopulation dynamics and production of Eudiaptomus gracilis (G. O. Sars) were investigated in two basins of differing water quality of Lake Balaton from February through December, 1977. One of the basins (Keszthely) is considered to be hypertrophic. the other (Tihany) moderately eutrophic. Plankton samples were collected at weekly intervals.The fecundity was 9.61 ± 3.39 at Tihany, and 16.53 ± 3.60 at Keszthely. The difference between the two basins was significant (P<0.1%). At Tihany the average number of eggs per m3 was lower by 36% relative to Keszthety.The number of nauplii differed only a little between the two basins with the exception of April, when at Tihany the amount of individuals was nearly two times as great as at Keszthely.In the case of younger copepodites (Stages I … III) the difference in individual numbers between the two areas of water was marked from February to June, while in other periods it proved to be small. At Tihany, the number of young copepodites was greater by 8%, on the average, than at Keszthely. The amount of larger copepodites (IV … V) relative to the total number of younger individuals of the population was by 63% resp. 77% smaller at Tihany and Keszthely.In the whole period of these studies the number of adults was less by 44% at Keszthely than at Tihany. Their amount relative to that of nauplii was smaller by 6% at Tihany and by 45% at Keszthely.At Tihany, the population biomass was at a constant high level during winter and spring (40 to 50 mg/m3), in summer values being lower (15 … 35 mg/m3). In the Keszthely‐Basin biomass showed more extreme changes, reaching a peak as high as 40 … 43 mg/m3 in April and November, but hardly exceeding 6 mg during July–August.During the period of investigation, total biomass in the Tihany‐Basin was 342 mg/m3, at Keszthely 204 mg/m3.Net biomass production‐two methods for estimation having been used – was higher in the Tihany‐Basin (17.25 and 33.83 KJ/m2), while in the Keszthely‐Basin it was considerably lower (13.06 and 9.50 KJ/m2).
Zur Aufbereitung von Oberflächenwässern unter Einsatz von Kalkhydrat
Authors: Walther H.‐J. 
Published: February 2007

AbstractDie zunehmende Aufbereitung stark belasteter Oberflächenwässer und Uferfiltrate durch Flockung mit Aluminium‐ oder Eisen(III)‐salzen ist für nicht wenige Länder mit einem erhöhten Import dieser Chemikalien verbunden. Unter bestimmten Bedingungen kann der Einsatz von Kalkhydrat den Bedarf an Metallsalzen vermindern oder nicht mehr erforderlich machen. Es wird ein Überblick des Standes der hydrochemischen Grundlagenforschung zur Aufbereitung stark belasteter Oberflächenwässer und Uferfiltrate unter Verwendung von Kalkhydrat gegeben.
Abwasserbehandlung und Stoffrecycling bei der Lederproduktion
Authors: Kaeding J. , Walther H.‐J. , Werner E. 
Published: February 2007

AbstractBei der hohen Inanspruchnahme des Wasserdargebotes ist es vielfach not‐wendig, zu wassersparenden Technologien einschließlich der Gewinnung von Werkstoffen überzugehen. Am Beispiel der Lederproduktion erfolgt die Erläuterung derartiger Möglichkeiten. Diese hochbelasteten und schwer zu behandelnden Abwässer sind nach einer sinnvollen Teilstrombehandlung unter gleichzeitiger Rückgewinnung der Haupteinsatzchemikalien Natriumsulfid und Chromsulfat wieder nutzbar. Bei der hohen Belastung von Abwasserteilströmen mit organischen Stoffen sollte außerdem eine Proteingewinnung angestrebt werden.
Influence of Temperature on the Toxicity of Phenol and its Chloro‐ and Nitro‐derivatives to the Fish Notopterus notopterus (PALLAS)
Authors: Gupta S. , Dalela R. C. , Saxena P. K. 
Published: February 2007

AbstractThere is determined the LC50 for 24 … 96 h of phenol, 2,4‐dinitrophenol and pentachlorophenol as sodium salt by static assay at water temperatures of 16, 23 and 36°C. In addition, the combinations of the three substances were tested in the same way. With decreasing temperature, the toxicity of the individual substances decreased by 6.5 … 22%, that of the mixtures by 10 … 87%; with rising temperature, the toxicity increased by 38 … 747% and 75 … 744%, respectively. The safety limits at 23°C lie between 0.3 μg/l for a synergistically acting mixture and 0.9 mg/l for an antagonistically acting one; for the individual substances this range is 3.5 μg/l to 0.5 mg/l.
The Concentrations of Cadmium, Lead and Copper in Filtrated Baltic Sea Water Samples Collected at Two Seasons in 1969
Authors: Gustavsson I. 
Published: February 2007

AbstractTwo research cruises on the Baltic Sea, in July and November of 1979, were made for investigating the Baltic Sea water for its contents of dissolved cadmium, lead and copper. Atomic absorption spectrophotometry and voltammetry were used as methods of investigation, the latter method having supplied slightly lower results. In the water layer of 0 … 50 m the cadmium concentrations were 0.03 … 0.05 μg/l and the lead concentrations were 0.1 … 0.2 μg/l, seasonal changes did not have any effect on them. The copper concentrations, on the other hand, were 0.4 … 1.2 μg/l in summer and 0.1 … 0.7 μg/l in autumn. Compared with ocean waters, the lead content is remarkably high. In anoxic deep waters of the Baltic Sea the concentrations of the three metals, especially that of cadmium, are very low (< 0.01 μg/l).
Zum Abbau von Formaldehyd durch adaptierte Bakterien
Authors: Behrens U. , Hannes J. 
Published: February 2007

AbstractMunicipal activated sludge was cultivated in a medium composed of formaldehyde, glucose and mineral salt. By passages with increasing formaldehyde content a bacterial culture was selected which remained active also at initial concentrations of 1 g/1 formaldehyde. With this culture, formaldehyde and glucose were oxidized simultaneously to formate and gluconate, which subsequently served simultaneously as substrate for the growth of bacteria. Glucose alone was also oxidized to gluconate, which then was used as substrate for growth. Formaldehyde alone was only oxidized. If the actual formaldehyde concentration was kept low, however, by fed‐batch cultivation, it was assimilated also through formate formation. The biochemical background and the importance of the findings for the purification of formaldehyde‐containing wastewaters are discussed.
Sedimentchemische Untersuchungen in Küstengewässern der Deutschen Demokratischen Republik Teil 17. Spezielle Untersuchungen zur Dynamik der Oberflächensedimente eines flachen Boddengewässers (Barther Bodden)
Authors: Nausch G. , Schlungbaum G. 
Published: February 2007

AbstractRepeated samples from the top 5cm of sediment in a homogeneous network of 100 sampling stations in the Barth bodden (mean depth—1.8 m) are analysed for dry weight, organic matter (loss on ignition), grain size distribution, total phosphorus and iron which is soluble in hydrochloric acid. The distribution of mineral and mud sediments (organic matter > 5%) follows the bottom topography: trays, closed basins and channels show the respective muddy concentrations; spits, ground waves and windexposed uplifts from depressions are mostly mineralic. The water depth has only a subordinate effect on distribution. After unquiet meteorological and hydrographic situations mainly the fine‐grained material is redistributed. As comparative investigations over four years show, due to this the distribution pattern is not changed fundamentally, so that the distribution of mainly mineralic, muddy and intermediate transition ranges can be mapped, unless this would be done according to surveys under extreme hydrographic and meteorological conditions. The individual parameters of the sediment quality show significant correlations between each other.
Biomass and Mineral Composition of Aquatic Macrophytes in the Hygam Wetland, Kashmir with Reference to Substrate Nutrients
Authors: Kaul S. 
Published: February 2007

AbstractThe wetland of 56 ha is situated at a height of 1565 m in the valley of the Jehlum river. Among macrophytes prevail Typha, Phragmites, Scirpus and Sparganium, and they are investigated at eight stations in the annual cycle. The mineral composition of the aboveground and belowground biomass and of the sediment was determined. The mean total biomass shows considerable variations, but also a pronounced annual variation with the summer maximum of 1445 g/m2 above‐ground and 1550 g/m2 below‐ground. The mineral constituents show clearly decreasing concentrations during the season of vegetation as far as potassium, calcium, magnesium and nitrogen are concerned, the nutrient contents lying between 0.041 and 1.9% P or 0.57 and 1.65 % N. In a regression analysis the biomasses show significant multiple regressions to concentrations of chloride‐ions, nitrogen and partly TPP and oxygen in the water and sediment.
Molmasseverteilung der organischen Stoffe im Prager Trinkwasser
Authors: Lischke P. , Chudoba J. 
Published: February 2007

AbstractThe water supply of Prague is based upon three different water resources: artesian groundwater and infiltrate of the Jizera river, water of the Vltava and Zelivka rivers. The processing techniques are different; consequently for the purpose of increasing capacity one has to search for the suitable raw water quality as well as for the optimum treatment process. An essential parameter for this is the contents of organic substances whose molar mass distribution is investigated by gel chromatography with the aid of Sephadex G‐10, G‐25 and G‐50. With respect to the total load of organic matter the Jizera shows the lowest values, in the Vltava the C.O.D. values are the highest, in the Zelivka the organic carbon shows the highest values. 80% of the organic substances in water have molar masses below 700. By flocculation 60… 70% of the C.O.D.‐Cr can be eliminated, the optimum removal of the high‐molecular substances occurring at pH = 6 and with 50… 60 g/m3 aluminium sulphate.
Eliminierung und Rückgewinnung von Metallionen aus Abwässern — eine Übersicht
Authors: Kümmel R. , Winkler F. , Beck R. 
Published: February 2007

AbstractThe present state and the trends of the recovery of heavy metals from wastewaters are presented. The classical precipitation techniques are insatisfactory due to increases of solubility in the presence of impurity ions and/or complexing agents. At present, ion‐exchange processes constitute the most frequently used method of metal recycling with an effective enrichment of metal ions. For the effective separation of metals from solutions of a low concentration the electrolytic reduction demands large electrode surface areas. In cells with fixed‐bed or fluidized cathodes one can obtain specific electrode surface areas of some 103 m2/mm3. For the future, processes of extraction and especially membrane separation will gain in importance. In the past few years, a large number of highly selective metal extracting agents as well as the liquid membrane permeation with suitable carriers were developed. Combinations of membrane separation processes with chemical reactions may attain the same importance, as e.g. ultrafiltration in connection with the fixation of metal ions to watersoluble polymers. In the long run, especially techniques will prevail which will not only result in metal enrichment but also in the recovery of the raw material water.
Bestimmung von Sulfid in Wasser mit einer ionenselektiven Elektrode
Authors: Neidhardt H.‐J. , Steinleitner H.‐D. 
Published: February 2007

AbstractFor the direct potentiometric measurement by means of a sulphidselective solidstate membrane electrode (as the reference electrode a calomel electrode with a salt bridge filled with 1M KNO3‐solution) there were mixed 25 ml sample with 25 ml sulphide‐antioxidant buffer (0.2 M ascorbic acid in 2 M NaOH, Ag2S‐saturated). Calibration is done with thioacet‐amide in the same buffer. This measuring arrangement determines sulphide concentrations of 1.5.10−6… 10−3 M. If the buffer is added to the samples in the ratio of 1 +1 immediately during sampling, the sulphide content will be stabilized by this for at least 24 h. The measuring method and its calibration are compared with other methods of calibration with Na2S and the potentiometric titration, the iodometric titration and the photometric determination. The method having been developed proves to be very selective and requires a minimum expenditure of time.
Efficaciousness of Certain Chemicals to Control Dracunculiasis — A Field Trial
Authors: Mehta S. , Srivastava R. C. 
Published: February 2007

AbstractTo prevent infection with Dracunculus medinensis, a carrier host, the copepod Cyclops, has to be controlled. After preceding laboratory investigations a field trial with well water and different additions of chlorine and sodium permanganate is carried out. The exposure is performed at an ambient temperature of 25… 40 °C and in bright and dark samples (5… 11 h of sunshine/d) as well as in the well. The residual concentrations of the two chemicals are an exponential function of the time of exposure with half‐times between 6 and 23 h for chlorine and 11… 30 h for sodium permanganate. The depletion of the two oxidizing agents under light is faster than in darkness. Dosage should be done in such a way that the LC90,24h after 24 h of exposure will not be fallen below; in a specific case, this guarantees at the same time that the permissible concentrations for drinking water will not be reached 96 h after addition. For this, initial concentrations of 30 mg 1 Cl2 or 50 mg/l KMnOr are necessary. Under these conditions, the Cyclops population had died on the seventh day after the application of chemicals, but after seven weeks it reached the original density again. With one application of chloride or sodium permanganate a week Dracunculiasis can be completely controlled.
Chemical Signals in Fishes: Theory and Application
Authors: Pandey A. K. 
Published: February 2007

AbstractIn this paper, a comprehensive survey is presented of the state of knowledge of the occurrence, chemical structure elucidation and biological importance of pheromones in fishes: fright and alarm substances, male and female sexual pheromones, intrasexual stimulants, school formation, social structure and individual recognition, pheromones and fish migration. Especially treated are the problems connected with the chemoreception under changed environmental conditions as well as the possibilities of utilizing pheromones or substances with a similar effect in fishery.
Studies on Primary Productivity and some Hydrochemical Aspects of a Polluted Water‐body of the Himalayan Jhelum Valley
Authors: Khan M. A. 
Published: February 2007

AbstractThe lake without any outlet (11 ha, 55000 m3, zmax 2,25 m) has a weak thermal stratification with maximum surface temperatures of 32.5 °C. The annual variation of temperature and depth of visibility is unimodal, with the maxima or minima in August. Phytoplankton consists mainly of Cyanophyceae. The primary production determined by the light‐dark bottle technique (oxygen method) varies in the annual variation between 0.3… 0.5 g m−2 d−1 C (winter) and 3.4… 4.6 g m−2 d−1 C (summer); as the annual means of 1975 and 1976 there were found 1.9 and 2.4 g m−2 d−1 C, resp., gross production at a utilization of 0.42… 2.85% of the radiation energy. The chemism is a well‐buffered hydrogen‐carbonate water (pH 8.1… 9.0) with 74… 90 mg/1 Na and 20.5… 31.5 mg/1 K and with a good nutrient supply (20… 40 μg/1 PO4—P and 100… 240 μg/1 NO3—N) at the same time.
Model of a Bacterial Culture Utilizing a Toxic Substrate in Continuous Flow Conditions
Authors: Teodorova S. E. , Sivriev I. K. 
Published: February 2007

AbstractA model is designed and discussed for the popular growth of a bacterial culture which grows by using a single toxic substrate. The model is based upon an enzymatic reaction with irreversible inhibition by the substrate. The stationary state of the system is represented and the range of its stability against the parameters of the model is defined.
Methode zur Bestimmung des Ammoniakstickstoffes in Gewässern
Authors: Hoffmann I. , Nagy B. , Schneider J. 
Published: February 2007

AbstractFor the spectrophotometrical determination of ammonia in surface water the reaction with hypochlorite and thymol in alkaline solution is used. Compared with other techniques, expenditure is low, the reagents are stable for a long period of time and the reaction is little dependent on external conditions. In 2 cm cuvettes there can be determined 0.05… 0.5 mg/l ammonia nitrogen. Comparative investigations carried out at nine sites in the area of the lake Balaton have revealed concentrations of 0.2… 0.7 mg/l ammonia nitrogen.
Ein Beitrag zur Anwendung der Regressionsanalyse im Zusammenhang mit der Schätzung der Primärproduktion im Großen Müggelsee (Berlin) für den Zeitraum 1979… 1982
Authors: Stellmacher R. , Nixdorf B. 
Published: February 2007

AbstractThe lake Müggelsee, which is important for the drinking water supply of Berlin, has been thoroughly investigated for some years with respect to its quality state and conversion of substances. To reduce working time and material expense for measuring of the primary production, with the aid of the results of series of investigations having been performed for years there are checked various mathematical‐statistical possibilities. Of the calculating methods studied the linear regression through the origin and the exponential approach provided the best approximation of measured and calculated results of the surface integral of the primary production as estimated from the production value of the optimum horizon for the type of the lake Müggelsee.