Photometrische Bestimmung der Zytotoxizität von Chemikalien

Two test methods are presented to assess the cytotoxicity of chemicals. On one hand the protozoonTetrahymena pyriformis and on the other the bacteriumPseudomonas aeruginosa is cultured in defined media containing the test chemicals. Test parameter is the quantity of living cells surviving exposure. The conversion of the tetrazolium salt MTT into formazan is equivalent to cell viability. A mixture of detergent and isopropanol is used to dissolve the blue formazan which is not soluble in water, prior to photometric measurement. For cetyltrimethylammonium bromide, benzyldimethyldodecylammonium chloride, dodecylbenzenesulfonic acid sodium salt, potassium dichromate, 4-toluenesulfonic acid sodium salt, and 4-nitrophenol the EC50-values (mol/l) in theTetrahymena pyriformis- (Pseudomonas aeruginosa) test system were: 10^?5,81 (10^?5,08); 10^?4,68) (10^?3,80; 10^?4,50 (10^?4,14); 10^?3,97 (10^?5,11); 10^?2,71 (10^?2,50) and 10^?4,00 (10^?3,64). — With the assays described here it is possible to measure a large number of samples by quick and simple means.     

Occurrence and distribution of triclosan in the German Bight (North Sea)

The potential of triclosan (TCS) acting as an endocrine disruptor has led to growing concern about the presence of TCS in the environment. In this study, seawater samples were collected from the German Bight during sampling campaigns conducted with the German research ships Gauss and Ludwig Prandtl. TCS was determined both in the dissolved phase and in the suspended particulate matters with concentrations ranging 0.8-6870 pg L⁻¹ and <1-95 pg L⁻¹, respectively. High concentrations of TCS were present in the estuaries of the Elbe and the Weser, indicating significant input of TCS by the river discharge. The correlation coefficient (R²) between the dissolved concentration and salinity was 0.79 for the data obtained from the Gauss cruise, showing an obvious declining trend from the coast to the open sea.     

Investigations on the leaching behaviour of irrigated construction elements

Objective  

In this paper, results regarding the leaching of trace elements out of mineral building materials under irrigation are presented.     

Using the paired comparison methodology to assess environmental values in the coastal zone of Ghana

Like many developing countries, Ghana is grappling with environmental issues, such as the degradation of coastal natural resources. In an attempt to ameliorate the current state of affairs, broad institutional arrangements and policy interventions have been put in place. However coastal natural resources are still being overexploited and the effects of this are felt more strongly by certain groups (such as women and the rural poor) than others. This has led to the argument pointing to an urgent need to include local resource users as active participants in environmental decision making and to incorporate their environmental values in the management of coastal natural resources. Using empirical data from women in two Ghanaian coastal communities, this paper highlights the importance of exploring how the environmental attitudes and values of women might be considered in the management of local coastal natural resources. It assesses effectiveness of the paired comparison methodology in this respects and how this method can be also used to prioritise their environmental concerns. The results show that in both areas respondents place the greatest importance on the coastal natural resources as sources of wealth creation and of food, values which are often described as being “anthropocentric”. The paper thus argues that having discovered that the ecological value placed on natural resources is low, initiatives that could win the support of people would be those that link the livelihood and wellbeing to coastal NRM. It emphasizes the fact that conservation cannot exist outside of people and social systems; nor will it succeed unless they are linked to the welfare of resource users.     

Effects of a Population Bottleneck on Whooping Crane Mitochondrial DNA Variation

Abstract: The Whooping Crane ( Grus americana ) is an endangered bird that suffered a severe population bottleneck; only 14 adults survived in 1938. We assessed the genetic effect of this human-caused bottleneck by sequencing 314 base pairs ( bp) of the mitochondrial DNA control region from cranes that lived before, during, and after this bottleneck. The maximum length of DNA amplifiable from museum specimens was negatively correlated with age, and only 10 of 153 specimens yielded the entire 314 bp sequence. Six haplotypes were present among the prebottleneck individuals sequenced, and only one of these persists in the modern population. The most common modern haplotype was in low frequency in the prebottleneck population, which demonstrates the powerful effect of genetic drift in changing allele frequencies in very small populations. By combining all available data, we show that no more than one-third of the prebottleneck haplotypes survived the human-caused population bottleneck. High levels of variation of substitution rates among nucleotide sites prevented us from estimating the prebottleneck population size. Our data will be incorporated into the captive breeding program to allow better management decisions regarding the preservation of current genetic diversity. These data offer the first glimpse into the genetic toll this species has paid for human activities.     

Biodegradation of aromatic compounds by white rot and ectomycorrhizal fungal species and the accumulation of chlorinated benzoic acid in ectomycorrhizal pine seedlings

The capability of different white rot (WR, Heterobasidion annosum, Phanerochaete chrysosporium, Trametes versicolor) and ectomycorrhizal (ECM, Paxillus involutus, Suillus bovinus) fungal species to degrade different aromatic compounds and the absorption of 3-chlorobenzoic acid (3-CBA) by ECM pine seedlings was examined. The effect of aromatic compounds on the fungal biomass development varied considerably and depended on (a) the compound, (b) the external concentration, and (c) the fungal species. The highest effect on the fungal biomass development was observed for 3-CBA. Generally the tolerance of WR fungi against aromatic compounds was higher than that of the biotrophic fungal species. The capability of different fungi to degrade aromatic substances varied between the species but not generally between biotrophic and saprotrophic fungi. The highest degradation capability for aromatic compounds was detected for T. versicolor and H. annosum, whereas for Phanerochaete chrysosporium and the ECM fungi lower degradation rates were found. However, Paxillus involutus and S. bovinus showed comparable degradation rates at low concentrations of benzoic acid and 4-hydroxybenzoic acid. In contrast to liquid cultures, where no biodegradation of 3-CBA by S. bovinus was observed, mycorrhizal pines inoculated with S. bovinus showed a low capability to remove 3-CBA from soil substrates. Additional X-ray microanalytical investigations showed, that 3-CBA supplied to mycorrhizal plants was accumulated in the root cell cytoplasm and is translocated across the endodermis to the shoot of mycorrhizal pine seedlings.