Präzipitation von Aluminium und Phosphat in Gewässern unter dem Einfluss von Versauerung

Precipitation of Aluminium and Phosphate Affected by Acidification Acidified waters often show elevated concentrations of Al (with up to 6 mg L^–1 being not unusual). A pH increase resulting e.g. from mixing with non‐acidified water or from biological activities may be linked with Al precipitation. Up to now, this phenomenon was described for acid mine drainages. This investigation focuses on a whitish precipitate naturally formed in a brook of an atmospherically acidified catchment in the Ore Mountains, Germany. Based on infrared spectra the precipitate was identified as an Al‐hydroxosulfate with crystal water. A simulation of natural conditions in the laboratory showed that Al precipitated only if sulfate or phosphate ions were added to the solution. In the case of sulfate being added, the infrared spectrum of the precipitate was similar to the natural precipitate. ²⁷Al NMR spectroscopy revealed tetrahedrally coordinated Al in some precipitates which evidences the participation of the tridecameric [Al₁₃O₄(OH)₂₄(H₂O)₁₂]⁷⁺ cation beside other polymeric Al cations. Precipitation experiments subjected to the given conditions showed that the phosphate elimination from solution with Al was much higher than with Fe. With Al and Fe added together, the P elimination rate was likewise high, and phosphate was bound onto Al in the precipitate. This was demonstrated by SEM‐EDX spectroscopy. Based on these results we present a possible reaction mechanism. The precipitation of Al together with P allows a significant retention of both elements in sediments because in contrast to Fe, Al immobilizes phosphate even under anoxic conditions.     

Bioindikation zur Verminderung von Stickstoffdüngerverlusten und der Stickstoffbelastung von Gewässern

Prerequisite to the nitrogen leaching from agricultural soils in spring is the ecologically optimum control of the first nitrogen fertilizer application. On the basis of investigations having been carried out for some years, a method for determining the optimum time of fertilization with the aid of phenological data is presented. The blossoming data of Anemone nemorosa proved to be a suitable sensitive indicator, their onset of blossoming is the optimum time for the first nitrogen application. In dependence on the height and variation of weather, in the subdued mountains this time is 90 … 116 d after the beginning of the year and corresponds to a temperaturetotal ≥ 5°C of 80 … 120°C or > 0°C: 160 … 230°C. Possibly, the leaf development of Alchemilla vulgaris or the first development of Poa pratensis are suitable as other bioindicators. The boundary conditions and disturbance variables of the bioindication are discussed. By the phenological date-determination of the beginning of fertilization the nitrogen losses can be reduced by 10 … 20% and the nitrate leaching can be considerably reduced especially in drinking-water protection areas.     

Zur Analytik von Chlorphenoxyalkansäuren und Chlorphenolen. Teil 2: Nachweis von Chlorphenoxyalkansäuren und Chlorphenolen in der Fischgalle

The bile liquid is preserved with ethanol and the protein is precipitated. Prefractionating is done by liquid-liquid extraction by chloroform and ethyl acetate. The extracts are column-chromatographically separated on Florisil and subsequently detected by thin-layer chromatography. For determining the identity of substances, the penta fluorobenzyl derivatives are prepared and chromatographed under the same conditions. Detection is carried out with the aid of ammoniacal silver nitrate reagency and ultraviolet irradiation. The highly polar conjugates of chlorophenoxyalkane acids and chlorophenols which are present in the bile are cracked by acid hydrolysis and then cleaned by re-extraction. In this way, 2, 4-D, MCPA, MCPP, 2,4-dichlorophenol and 2-methyl-4-chlorophenol were detected from Salmo gairdneri. 6… 21 d after the application of the herbicides in the catchment area their concentration in the fish bile amounted to about 200 mg/l, 90% of them having been conjugates. Thus, the biliary excretion of xenobiotic substances offers an important new aspect of biomonitoring by means of fish tests, especially in the range of subacute and chronic toxicity.     

Bestimmung von Organochlorpestiziden in Schlämmen und Sedimenten

A method for the determination of organohalogens by gas chromatography using electron capture (EDC) and mass-spectrometric (MS) detection was developed for sediments from lakes and sludges of water treatment plants. The method was described and separate techniques for sample preparation were investigated to compare the retrieval rates and the best approach to the “real value”. With the help of solid-liquid-phase- and liquid-liquid-phase extraction sulphur, most of the organosulphur compounds and carbon acids were effectively removed. The compounds were identified by comparing temperature programmed retention indices with those of reference compounds and by high-resolution GC/MS.     

Konzepte zur Mobilitätsabschätzung von Schadstoffen in Boden- und Abfallmaterialien

Concepts for the Evaluation of Contaminant Mobility in Soil and Waste Materials Elution tests (S4, pH_stat, and SDS test) are presented, enabling the evaluation of the mobility of hydrophilic/hydrophobic and inorganic/organic contaminants in soil and waste materials. While elution tests for estimation of the mobilization potential of hydrophilic substances are performed following the pH_stat method, for hydrophobic species surfactant-containing eluents are used. The individual parameters of the elution process are selected assuming a "worst-case" scenario. In principle, because of economic reasons, detailed analytical investigations should be preceded by relevant screening tests.     

Nährstoffbelastung und Trophie von Talsperren der DDR Teil 1: Einzugsgebietsstruktur und Nährstoffsituation

Statistically secured relations between nutrient concentrations in the water and characteristics of the catchment areas can be proved for the storage reservoirs of the GDR. The o–PO₄ concentration during the full overturn in spring shows a close relation to the population density of the catchment area. Existing differences of concentration between drinking-water and industrial-water storage reservoirs can be attributed to different degrees of worthiness of protection of the catchment areas and to differences of the water morphology. The NO₃ concentration is closely correlated with the proportion of agriculturally used area in the catchment area. The mass ratio NO₃–N: o–PO₄–P mostly lies above the limiting range of the limitation of nitrogen (> 12: 1), so that phosphorus becomes the central quantity of a possible control of the trophic level. Especially for drinking-water storage reservoirs in the weakly eutrophic range the reduction of the P-load is necessary and it has a high trophy-improving effect here.     

Prognose von Acidität,Eisen- und Sulfatkonzentration im Grundwasser von Bergbaugebieten

The hydrochemical fundamentals of the origination of high concentrations of iron and sulphate at an acid reaction of ground waters of exhausted open-cast coal mines are explained, and a technique based on representative sampling and oxidative treatment of aqueous suspensions with atmospheric oxygen for predicting the average load over years and decades on the basis of the analytical values has been developed and tested in the Central German area. Experimentally obtained relationships (weatherable pyrite/reaction rate, pH-variation/buffering capacity of soil, total iron content/pH-value) are stated.     

Gewässergütebewertung und Bewertung von Abwasserfahnen in Rhein und Main auf der Basis mikrobieller Enzymaktivitäten

Quality Mapping of Surface Water and Assessment of Treated and Untreated Waste-water Inputs into the Rhine and Main River Based on Microbial Enzyme Activities Microbial enzyme activities are used for an extension of the traditional quality mapping of surface water. In the following study, the enzymatic parameters were proved and validated on samples from various creeks and rivers in Baden-Württemberg and on samples gathered from the Rhine and Main Rivers (Germany). The test parameters should also be used for the control and the preservation of the capacity of the biological self-purification, which is the only natural and essential process in drinking-water conditioning of surface water. Main subject of the surveys was the development of criteria for an assessment of the measured enzymatical inhibition effects. Therefore, classes of inhibition and indices of inhibition are defined.     

Zum Einfluß von Rückständen von Zink- und Bleiverbindungen im Wasser auf die Assimilation von Fontinalis antipyretica

The carbon-dioxide assimilation of Fontinalis antipyretica is inhibited by 100 mg/1Zn²⁺ or Pb²⁺, without a lethal effect being caused. With increasing time of exposure from one to six days the threshold value of toxicity is lowered and at the same time the net assimilation is reduced within the range of concentration of 0.1 mg/1. In the ecological optimum of the environmental conditions the toxicity is weaker than under other unfavourable environmental conditions at the same time. Therefore, the photoecologically optimum illumination of 1200 lx is an effective bioprotector against phytotoxic lead ion concentrations, so that at 1200 lx also at a comparatively high load a positive photosynthesis balance can be maintained. In the dark, in the first hour after the application of the lead ions dissimilation is a function of concentration, subsequently the respiration differences decrease very much in the range between 0 and 100 mg/1 lead(II)-ions. Stimulating effects could be demonstrated only by 0.01 mg/1 Pb²⁺ and only for the carbondioxide assimilation.     

Die Auswirkung von Tensiden und das Verhalten von Bakterien gegen-über grenzflächenaktiven Verbindungen

An investigation was made into the effects of seven anion-active tensides and one non-ionic tenside on the growth and respiration of 19 strains of the bacteria genera Proteus, Pseudomonas, Aerobacter and Sarcina. A nutrient broth with phosphate buffer and partly glucose addition was used as the culture medium. Tenside was added either at the beginning of tests in the lag-phase of cultures or during the logarithmic growth phase. In addition, the development of resistance or adaptation were tested by establishing subcultures. The inhibitory effect of tensides depends on the combination of tenside/species of bacteria, gram-positive bacteria being more sensitive and the inhibitory effect being lower in their logarithmic growth phase. The time course of the inhibition of respiration after the addition of tenside to the medium shows different types of inhibition and adaptation, considerably extended lag-phases occurring frequently.     

Zur statistischen Auswertung von mikroskopischen Plankton- und Partikelzählungen

The Poisson distribution is required for the evaluation of counting results. Its availability can be checked with the dispersion index and graphically with a probability sheet. It is shown by an example that with increasing particle density the deviation from the Poisson distribution increases and how these anomalies become visible in the dispersion index and the per-cent error of the count. For the calculation of confidence intervals, a simple approximation formula and the asymptotic behaviour with growing random sample size are represented. The phenomena of over- and under-distribution as well as of “contagion” (Neyman distribution) are mentioned, and the high-speed method of counting according to Tippett and the variance-analytical evaluation methods are referred to.     

Photochemischer und photokatalytischer Abbau von Carbamazepin,Clofibrinsäure,Iomeprol und Iopromid

Photochemical and Photocatalytic Degradation of Carbamazepine, Clofibric Acid, Iomeprol and Iopromide