Biomedical subjects

Adolf Eisentraeger

Publications and source records attributed to Adolf Eisentraeger.

7 recordsLinked to original sources

PubMed2006

Influence of laboratory storage on the organic contaminant content and water-extractable ecotoxicological potential of soil samples.

At present there is a high level of uncertainty about whether or not soil samples, which are required to be toxicologically characterized, could be preserved without affecting their toxicological characteristics. In the existing DIN/ISO standards for soil investigations, there is no documentation on the storage of soil samples after collection for (eco-)toxicological investigations. Furthermore, procedures for receiving justifiable and verifiable results from soil samples are quite vague. Therefore, the stability and changes in the biological effects of different soil contaminants were investigated by varying the storage conditions and the storage times of the soil. The limitations of storing soils could therefore be subsequently outlined. Recommendations for the optimization of storage conditions for back-up soil samples were made. These recommendations have the capability of finding entrance into DIN/ISO standards.

Environmental Monitoring↗

PubMed2006

Electrical discharge machining: occupational hygienic characterization using emission-based monitoring.

Hazardous potential in industrial environments is normally assessed by means of immission-based sampling and analyses. This approach is not adequate, if effects of specific technical adjustments at machine tools or working processes on hygienic parameters should be assessed. This work has focused on the optimization of a manufacturing process (electrical discharge machining, EDM), with regard to risk reduction assessment. It is based on emission analyses rather than immision analyses. Several technical EDM parameters have been examined for their influence on air-based emissions. Worktools and workpieces used have a strong influence on aliphatic compounds and metals but not on volatile organic compounds (benzene, toluene, ethylene-benzene and xylene (BTEX)) and polycyclic aromatic hydrocarbons (PAHs) in air emissions. Increasing the dielectric (mineral oil) level above processing location decreases BTEX, chromium, nickel and PAH emissions. Aliphatic compounds, in contrast, increase in air emissions. EDM current used has a positive relationship with all substances analyzed in air emissions. Indicative immission concentrations, as can be expected under EDM conditions, are estimated in a predictive scenario. The results of this characterization give rise to an important conclusion in that risk assessment so far has been using incorrect parameters: total aliphatic compounds. Maximum level of chromium is reached long before limit values of aliphatic compounds are exceeded. Because of the fact that metals, like chromium, also have a higher hazardous potential, metal analysis should be introduced in future risk assessment. This experimental approach, that captures total emission of the electrical discharge machine, and is not solely based on immission values, has lead to a better understanding of the production process. This information is used to extract recommendations regarding monitoring aspects and protection measures.

Air Pollutants, Occupational↗

PubMed2004

Light-emitting diodes for the illumination of algae in ecotoxicity testing.

Ecotoxic effects of chemicals, preparations, and environmental samples are routinely quantified in standardized algae growth inhibition tests using microalgae like Desmodesmus subspicatus. The intention of this investigation was to prove the suitability of light-emitting diodes (LEDs) as an alternative to tubular discharge lamps in algae growth inhibition tests. This was approached by demonstrating that growth of algae was similar with both illuminating devices. Growth factors of growth controls were determined using LEDs. Growth curves of different light intensities of LEDs were compared with those of tubular discharge lamps. By testing certain chemicals with both illumination methods comparable results for E(r)C50 values were obtained. It could be shown that small-scale construction of incubators using LEDs is possible and could be advantageous, especially for the illumination of algae in 96-well microplate growth inhibition assays.

Biological Assay↗

PubMed2003

Comparative studies on algal toxicity testing using fluorometric microplate and Erlenmeyer flask growth-inhibition assays.

Two fluorometric microplate algae growth-inhibition assays with a liquid volume of 2 mL and 200 microL per well are presented, and comparative studies on the toxicity of chemicals are carried out with Erlenmeyer flask assays. The test procedures are in accordance with the standards ISO 8692 (DIN 38412 L9 and EN 28692), OECD 201 and DIN 38412 L33. By testing four toxicants several times laboratory internal repeatability is proven. Statistical evaluation demonstrates that the results obtained with both the 24-well and the 96-well microplates are nearly identical with the results of the Erlenmeyer flask assay. Therefore, the microplate growth-inhibition assays can be applied for the testing of a wide range of chemicals and environmental samples if some methodical aspects are taken into account. Apart from that, there is a strong need for harmonization if the dependency of the EC values on the toxicological endpoint is considered.

Eukaryota↗

PubMed2002

Biodegradability testing of synthetic ester lubricants--effects of additives and usage.

The optimised biodegradability test system "O2/CO2 Headspace Test with GC-TCD" is used for the assessment of synthetic ester lubricants. The effects of both additives and usage on biodegradability are examined and discussed. Ester based cutting fluids and hydraulic fluids with and without additives are used under defined conditions at machine tools and hydraulic and plain bearing test benches. The lubricants are characterised additionally with respect to kinematic viscosity, acidity and elemental composition. Furthermore, a formulated mineral oil is characterised before and after usage at an hydraulic test bench. The results clearly show that the mineral oil is far less biodegradable than the ester oils and that their biodegradability is not affected by usage. Biodegradability of the ester oils is mainly depending on the characteristics of the base fluids and not affected by the additives. Antioxidants are influencing stability respectively biodegradability indirectly, since they prevent oxopolymerisation effects. Other effects of usage on biodegradation are not detected. In this context, the antioxidants ensure ready biodegradability and have a positive effect on the environmental fate of synthetic ester lubricants.

Antioxidants↗

PubMed2002

Determination of urease activity in soils by carbon dioxide release for ecotoxicological evaluation of contaminated soils.

A method for the quantification of urease enzyme activity has been set up, which is based on the quantification of carbon dioxide set free into the head space of gastight vessels. The method can be applied for ecotoxicological characterisation of contaminated soil samples besides other methods like soil respiration measurements or nitrification inhibition tests. The sieved soil sample can be incubated under nearly natural conditions with an adjusted water content of about 50% of the water holding capacity. Ammonia or urea do not need to be extracted, since carbon dioxide release is correlated to urease activity. Thus carbon dioxide release is a direct result of urease activity which can be measured in the head space using gastight syringes and gaschromatographic equipment. The urease activity is determined by comparing the carbon dioxide release of incubation vessels with and without urea supply. The applicability of this method has been demonstrated by experiments with N-(n-butyl)phosphoric triamide (NBPT), copper ions and zinc ions as known inhibitors of urease activity.

Carbon Dioxide↗

PubMed2002

Assessment of the influence of use on ecotoxicological characteristics of synthetic ester lubricants.

Synthetic ester lubricants need optimisation about their technical and their ecotoxicological characteristics. To determine the ecotoxicological potential the required examinations can be based on the procedure for a risk assessment of chemicals. At present risk classification of lubricant oils is carried out with new oil fluids that are normally prepared before application in aqueous bioassays. In order to improve the ecotoxicological characteristics of some lubricant oils, the quality of the preparation method has been optimised. The resulting preparation protocol leads to aqueous extracts of the oil fluids that can be tested using biological assays. The extent of the changes of the chemical composition caused by the use as well as the ecotoxicological effects caused by additives have to be taken into consideration. For this reason various used lubricants are tested in addition to new oil fluids. In this work various lubricant samples were examined with standardised bacterial growth assays with Vibrio fischeri and Pseudomonas putida, luminescence inhibition assay with V. fischeri, survival assay with Daphnia magna and algal growth inhibition assay with Scenedesmus subspicatus. The chemical characterisation of the aqueous extracts included the determination of pH, conductivity, heavy metals, the content of dissolved organic carbon, inorganic anions and the content of phosphorus. The results emphasize the thesis that environmentally acceptable lubricants can undergo a change of their ecotoxicological potential during the use. Some of the substances that are normally added to base fluids in order to enhance the applicability of the oils may possess a high toxicological potential.

Animals↗