The phylogeny of archaebacteria,including novel anaerobic thermoacidophiles in the light of RNA polymerase structure

DNA-dependent RNA polymerases of archaebacteria are distinct from those of eubacteria both in structure and in function. They show similarities to those of the eukaryotic cytoplasm. Extremely thermophilic anaerobic sulfur-respiring archaebacteria isolated from solfataric waters represent four different families, the Thermoproteaceae, the “stiff filaments”, the Desulfurococcaceae and the Thermococcaceae, of a novel order, Thermoproteales. Together with the Sulfolobales, they form the second branch of the urkingdom of the archaebacteria besides that of the methanogens and extreme halophiles. Thermoplasma appears isolated.     

Untersuchungen zur Nachhaltigkeit der Sanierung von Tributylzinnkontaminiertem Hafensediment durch Landablagerung

To allow ships to pass, most harbours have to be liberated from sedimented material. These sediments often contain high concentrations of tributyltin (TBT), which is used as a biocide in antifouling paints. Thus, the problem of a disposal which is acceptable with respect to a minimum risk for humans and the environment arises. The aim of our project was to assess land deposition as an alternative in dealing with TBT-contaminated harbour sediments. Therefore, we followed the biological degradation of TBT under aerobic and anaerobic conditions at different temperatures using defined laboratory experiments, and got important information about the land deposition, performing field measurements including biomonitoring. The biological degradation of TBT is faster under aerobic conditions and with increasing temperature. The half-lives found show the dependency of the degradation rates on the temperature between 5–55°C. The degradation rate determined for water under the same conditions (just biological degradation, without photolysis) is almost 4 times higher than in sediment. The field studies showed degradation rates of a maximum of 10–15% per year in untreated sediment and 30% per year in restacked sediments. We did not observe any interference of released TBT with ground water or surrounding areas. The TBT uptake in plants was low. Based on our results a multidimensional risk evaluation was performed, concerning the TBT and its degradation products dibutyltin (DBT) and monobutylin (MBT) released from the deposition areas. The land deposition appears to be a sustainable solution for dealing with TBT-contaminated harbour sediments.     

Polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in urban air and deposition in the United Kingdom

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been monitored in air and deposition at four UK urban sites (London, Cardiff, Manchester and Stevenage) since the beginning of 1991; data from the first 2 years are presented here. Median Σ2,3,7,8-substituted PCDD/F concentrations in air were 3.2, 4.0, 3.5 and 2.6 pg/m³ respectively for London, Cardiff, Manchester and Stevenage. Median Σ2,3,7,8-substituted PCDD/F deposition fluxes were 1.5 ng/m²/day in London, 1.4 ng/m²/day in Cardiff and Manchester and 0.79 ng/m²/day in Stevenage. Seasonal variations in the PCDD/F concentrations were observed at all sites for both air and deposition, with concentrations/fluxes generally elevated during the winter.