Distribution Pattern of Benthic Invertebrate Communities in Traunsee (Austria) in Relation to Industrial Tailings and Trophy

Traunsee, an oligotrophic Alpine lake, has suffered from inputsof industrial tailings (soda- and salt-mining industries) forseveral decades. The effects of the industrial sludges on thespatial distribution of the littoral and profundal invertebratefauna was investigated along three transects at five dates. Inthe littoral zone, no negative impacts were found. A distinctgradient in faunal composition and diversity was, however,observed along a profundal transect relative to the distance fromthe waste emission. Near the industrial input, the enhanced pH,the substrate instability, and the poor sediment quality forsubstrate- and deposit-feeders were the main factors that loweror prohibit colonization of the industrial sludges. Along atransitional zone between the waste emission and the deepestbasin, recolonization was delayed, but did occur as soon aslayers of a few mm natural sediment seal the sludge. Mobile,epibenthic organisms are the first to settle these areas, whereasrecolonization by tube-building oligochaetes and chironomidsrequires thicker sealings of the industrial sludges. Differencesin the abundance of benthic invertebrates at different profundalsites were not only related to the waste emission, but also tothe influence of the main tributary, the River Traun. Theenhanced availability of allochthonous organic matter wasprobably responsible for high densities of tubificids near theinlet in the South of Traunsee. Moreover, a higher proportion oftolerant oligochaete and ostracod species in the lower profundaloutside the influence of the industrial tailings was interpretedas reflecting the increased trophy of Traunsee in the 1970s,which forced sensitive species to shift to the upper profundalwhen the oxygen climate deteriorated.     

Health Impact Evaluation of Boron in Drinking Water: A Geographical Risk Assessment in Northern France

Objective: To evaluate health impact of boron in drinking water. Methods: A regional scale geographical study in Northern France was conducted. Assessment of boron blood levels in a group of 180 healthy individuals and correlation with boron content in drinking water were followed by an assessment of health indicators such as birth rates, mortality rates, and sex ratios in zones of different boron content in drinking water. Results: After necessary adjustments, men living in municipalities with more than 0.30 mg/L of boron in drinking water had elevated but not significant boron blood levels compared with those living in municipalities with boron water levels of less than 0.30 mg/L (159.1 versus 123.0 ng/g; p > 0.05). The standardized birth ratio adjusted for the reference geographic zone and calendar time period was 1.07 and 1.28 in the low and high (>0.3 mg/L) boron content municipalities, respectively. The birth rate in municipalities with high boron content in drinking water was higher than that of the reference geographic zone and of the French general population (p < 10^-4). The standardized mortality ratio adjusted for the reference geographic zone and calendar time period was 0.94 and 0.92 in the low and high boron content municipalities, respectively. The mortality rate in municipalities with high boron content in drinking water was less than that of the reference geographic zone and of the French general population (p < 10^-3). No statistical difference was noted in the male–female sex ratios between the different municipality zones (p = 0.45). Conclusions: The results of this study do not support the idea of a deleterious effect of boron on human health, at the boron water level contents found in this specific region. In fact, there is a tendency toward a beneficial effect with low-dose environmental exposure (less than 1 mg/L of boron) in drinking water.     

DDT und Metaboliten in Sedimenten Berliner Gewässer

Sediment samples from rivers and lakes of Berlin (Germany) were analysed for their contamination with organic compounds by means of qualitative and quantitative GC/MS analysis. The principal compounds detected were PAH, organotin derivates, several classes of chlorinated, brominated and mixed halogenated compounds and some of their related metabolites. The DDT metabolites DDD, DDE, DDCN, DDMU and DDMS were the most abundant compounds of halogenated pesticides in a wide range of samples. The main metabolite determined was p,p′-DDD, with concentrations up to 1230 μg/kg dw. The parent DDT compound was detected in only a few samples. The acute cytotoxicity of selected DDT-metabolites was determined with the permanent cell line RTG-2 from the gonads of the rainbow trout (Oncorhynchus mykiss). The results indicate a high cytotoxic potential of these metabolites. The oestrogenic potential was determined by the Dot-Blot/RNase-Protection-Assay an the order from o,p′-DDT>p,p′-DDMS>p,p′-DDMU≥p,p′-DDCN. Risk assessments based on chemical analysis of DDT, DDD and DDE alone is not able to estimate the real toxic potential of DDT and its metabolites. The development of a method for bioassay directed assessment seems to be an effective strategy to solve this problem. Especially scarce or not available data of combinatory effects, differences between different trophic levels and their availability to biota and low knowledge about the metabolism in situ as well as the enantioselective characteristics of most chiral DDT metabolites warrant future analyses.     

Alternative Non-market Value-Elicitation Methods: Are the Underlying Preferences the Same?

We advocate a more formal structural approach for comparing WTP for non-market or pre-test-market goods conveyed by fundamentally different preference elicitation mechanisms. Seven independent samples of respondents were asked to value the identical good. Elicitation methods include one actual purchase and six widely used hypothetical choice formats. Using a common underlying indirect utility function (and stochastic structure) allows data for different elicitation methods to be used independently, compared pair-wise (as in much of the earlier literature) or pooled across all samples in one unified model with heteroscedasticity across elicitation methods. Our differences in estimated WTP for the individual models are typical of earlier findings. However, pooled-data models that allow for heteroscedasticity reveal that while there are substantial differences in the amount of noise in the different samples, a common underlying systematic component of the preference structure cannot be rejected for at least four (and possibly five) of these seven elicitation methods.     

Aktivierung,Aktivität und Inhibierung des Rindertrypsins

Trypsin is a prototype of a large group of enzymes belonging to serine proteinases. The X-ray crystal-structure analyses of its proenzyme trypsinogen, of the active trypsin and of their complexes formed with the pancreatic trypsin inhibitor (PTI) have considerably enhanced our understanding of the mechanisms of activitation, action and inhibition. The trypsinogen is an incompletely folded molecule. Its substrate-binding site becomes only completely fixed upon the enzymatic cleavage of an N-terminal peptide. The contact regions of trypsin and PTI are almost complementary. The complex formed is a (stable) intermediate in the normal tryptic substrate-cleavage reaction.