Stability of tetracycline in water and liquid manure.

The objective of this study was to establish a suitable model for the prediction of the environmental stability of antibiotics in water and liquid manure. The model consists of incubation systems for solutions with installations for stirring ventilation. It was used to examine the stability of tetracycline in ventilated and unventilated Ringer's solution and liquid pig manure for a period of 8 days. Tetracycline concentrations decreased significantly during the experiment. The fastest degradation was observed in ventilated liquid manure. The test might be used as a screening test for the determination of the degradation half-life of antibiotics in the first phase of an environmental safety study according to directive 92/18/EEC.

[Preliminary results of microbiologic studies of the processing of contaminated plastics (recycling)]. / Erste Ergebnisse zu mikrobioloischen Untersuchungen bei der Verarbeitung kontaminierter Kunststoffe (Recycling).

Spores of Bacillus subtilis were mixed with 200 g of polyethylene-granulate. The result was an initial concentration of about 10(5) colony-forming-units per g polyethylene. This mixture passed an injection-moulding machine. The formed material was collected under sterile conditions, cut into pieces of about 1 cm and analysed for bacteria. In 4 of 23 cases Bacillus subtilis was present after passing the injection-moulding machine. A quantitative determination had the result, that about 3% of the spores could be found after the process of passing the injection-moulding machine.

The determination of diethylstilbestrol (DES) in the faeces and tissues of chickens treated with DES and in the faeces and tissue samples of calves, lambs and chickens collected from various areas of Turkey.

Diethylstilbestrol (DES) analyses were carried out on muscle, liver, kidney and faeces samples of 20 control and 20 experimental broilers to which 5 mg DES/day had been given orally for a period of 7 days. The treated samples were analysed using the Radioimmunoassay method. The removal time of DES from the tissues was determined. Five days following the final administration of DES, its faecal concentration was 151 ppb. However, 7 days after the final administration faecal DES concentrations increased again. On the first day after the final DES administration, DES concentrations in the liver, muscle and kidney were 0.78, 0.74 and 1.33 ppb, respectively. While these values measured on the final day were within the range of the control values. There was an increase of DES in plasma at the end of the experimental period. A total of 1811 muscle, liver, kidney and faeces samples of calves, lambs and chickens and feed samples collected from various areas in Turkey were analysed for the presence of DES. Positive samples for chicken feed was 36.9%. Also 1.9% of the chicken faeces samples were DES positive. All other samples were negative for DES.