Zur Toxizität einfacher und komplexer Cyanide gegenüber Wasserorganismen

The toxic effects of alkali cyanide, complex cyanide-containing heavy metal salts—as of iron, cadmium, copper, nickel and mercury—were investigated according to standard methods with the aid of the test organisms Poecilia reticulata (guppy) as well as the green alga Ankistrodesmus falcatus (β- bis α-mesosaprobic). Since various complex compounds can be photolytically decomposed, also discontinuous light-dark phases were used. As discussed equilibrium calculations have shown, inter alia also the pH-value is important in the fish organisms used with different reactions to ions and molecularly dissolved compounds. The results are summarized in tables and graphic representations, the substances investigated being classified into groups with “strong” and “high” toxic actions.     

Kurzzeit-Toxizitätstests zur Messung der Toxizität von Chemikalien gegenüber Belebtschlamm

Short-term Toxicity Tests for the Measurement of Toxicity of Chemicals Towards Activated Sludge. To avoid severe damage to the activated sludge of a wastewater treatment plant it is necessary to control the sludge activity by means of biological test systems. Especially the short-term respiration assay and the dehydrogenase assay with resazurin as a redox-dye seem to be appropriate for this monitoring program. The practical performance of both test systems was optimized in some essential points. With the help of several reference substances both monitoring systems were tested for practical use as short-term toxicity tests. The results of the investigations showed that the inhibitory concentrations measured in both test systems were partially very different. In monitoring experiments with laboratory-scale wastewater treatment plants it could be shown that a positive correlation between respiration activity and dehydrogenase activity is not always given. Furthermore, a pH-dependent toxicity could be demonstrated for several substituted phenols.     

Vergleichende aquatoxikologische Ergebnisse mit ausgewählten Wasserschadstoff-Gruppen und repräsentativen Wasserorganismen

Salmo gairdneri, Cyprinus carpio, Poecilia reticulata, Leuciscus idus melanotus, Asellus aquaticus, Ankistrodesmus falcatus and Monoraphidium griffithii were exposed to four growth regulating herbicides, four photosynthesis toxicants, lindane, an anionactive tenside, KCN and Na₃[Cu(CN)₄] in standardized toxicity tests. The biochemical degradability of the substances was tested with activated sludge. In order to test the possible effects in waters there should be used Salmo for the oligosaprobic zone. Poecilia as well as Ankistrodesmus and Monoraphidium provide reliable estimations for β-mesosaprobic waters. With respect to the longer-term permission of plant protection products, besides Salmo there can be recommended also Leuciscus.     

Zur Toxizität von Butonat,Trichlorfon und Dichlorvos gegenüber Escherichia coli und Enterobacter aerogenes

Butonat, Trichlorfon und Dichlorvos sind für Escherichia coli und Enterobacter aerogenes erst in relativ hohen Konzentrationen akut toxisch. Eine negative Beeinflussung der Wachstunisrate tritt im Konzentrationsbereich ≧1000 mg 1⁻¹ (Butonat, Trichloifon) bzw. ≧250 mg 1⁻¹ (Dichlorvos) ein. Bis zu diesen Konzentrationsbereichen werden die Wirkstoffe durch die Bakterien inaktiviert bzw. metabolisiert. Die Bestimmung der Wachstunisrate erfolgt über den Sauerstoffverbrauch der Kultur im SAPROMAT AP 12. Die Wirkstoffkonzentrationen werden dünnschichtchromatographisch analysiert.     

Zur Aquatoxizität ausgewählter Harnstoffherbizide und zu ihrer Kategorisierung als Wasserschadstoffe

Eight urea herbicides, as are used for weed control, are investigated for their effect on the green alga Ankistrodesmus falcatus and the warm-water fish Poecilia reticulata and found to be highly toxic for the test alga or highly to moderately toxic for the fish. If other criteria (acute toxicity to warm-blooded animals, carcinogenicity and biochemical degradability) are taken into account too, the tested herbicides have to be classified as very dangerous water pollutants. Legal sanctions to be applied in cases of exceeded limiting values are discussed.     

Vergleich ausgewählter Elutionsverfahren zur Beurteilung der Mobilität von Metallen

Comparison of Selected Elution Procedures for the Valuation of the Mobility of Metals from Sediment and Sewage Sludge Several methods of extraction are generally used to evaluate environmental or ecological toxicity and deposition of waste material. In this paper, the application of the German standard methods DIN 38414-S7, DIN 38414-S4, pH_stat method, “Schweizer method” (elution test, Switzerland), and some variants of the pH_stat method on two very different samples are described. A rudimental sediment and a municipal sewage sludge are chosen as sample materials. The metal contents of extract solutions are determined by ICP-OES. The results of the DIN-S4 extractions depend definitely on the mechanic way of movement, i.e. the amount of heavy metals which are mobilized out of the samples differs considerably. In fact, DIN-S7 in combination with DIN-S4 is not sufficient to estimate the mobility of heavy metals. Solid samples should only be evaluated by applying a combination of several methods of extraction. The usefulness of the pH_stat method for an evaluation is discussed.     

On the Toxicity and Biodegradation of Cationic Surfactants Über die Toxizität und den biologischen Abbau kationischer Tenside

Three ammonium halide type surfactants were tested under standard laboratory condition for biodegradability and acute toxicity to Daphnia magna and in the Microtox test with the luminescent bacterium Photobacterium phosphoreum. The tested compounds are dimethyldistearylammonium chloride (DSDMAC), cetyltrimethylammonium bromide (HTMAB) and cetylbenzyldimethylammonium chloride (HBDMAC). The results indicate DSDMAC is less toxic than the other two surfactants and that it biodegrades rapidly at both lower (2.5 mg/L) and higher (10 mg/L) concentrations.     

Bestimmung der Aktivität von Belebtschlamm über die Geschwindigkeit der Biosynthese von Aminopeptidasen

The authors describe a possibility of a fast determination of the metabolic activity of various activated sludge samples. There is not used the sludge property of digestion, but the biosynthesis of aminopeptidases. Egg albumin has been found to be the optimum standard indicator. The activity of the investigated activated sludge is derived from the rate of the biosynthesis of aminopeptidases. The technique proposed can be used also for determining the toxic effects of different substances on activated sludge.     

Vergleichende Untersuchungen über das Phosphataufnahmevermögen ausgewählter Bakterienarten

The P-uptake by Acinetobacter calcoaceticus, Pseudomonas aeruginosa and Escherichia coli is determined in batch culture with peptone/glucose/sodium chloride or peptone/acetate/sodium chloride as substrate at 60 to 120 mg/1 orthophosphate for 20 h with cell densities of 2 · 10⁷/ml (Acinetobacter) or 1.2 · 10⁹. The measurements were carried out by means of an Na₂HPO₄ (³²P) addition of 95 to 420 kBq. During the stationary phase the bacteria achieved the following P-contents in the biomass in fg/g bacterium: Acinetobacter 6 to 13, Pseudomonas 0.2 to 0.6, Escherichia 0.04 to 0.09; during the phase of growth Acinetobacter achieved 40 to 100 fg/bacterium. Acetate as the substrate did not result in any increase of the P-uptake. The maximum accumulation with Acinetobacter was 13 % P in the dry substance.     

Immersionskalorimetrische Einschätzung der Adsorptionsfähigkeit von Aktivkohlen gegenüber organischen Stoffen aus wäßrigen Lösungen

In comparison with the conventional methods for testing the adsorptive capacity of active charcoals, the author presents a new technique. The measuring possibilities of the immersion calorimetry are used. This measuring technique is based on the determination of the interaction of active charcoal with liquid adsorptives. The immersion heat referred to one mol adsorptive is used as the measure. Due to simplifying assumptions and a micropore volume of active charcoal measured with water vapour, immersion-calorimetrically relative equilibrium constants can be determined. By the example of phenol and indol, the adsorptive capacity of several domestic and foreign samples of active charcoal is assessed on the basis of the difference of the immersion heats in benzene and water.