Chlorinated hydrocarbons in sediments of the Elbe River and the Elbe Estuary

Eight sediment samples collected between Hamburg and Cuxhaven were analysed for organic micropollutants. Using three different methods the following compounds were determined: α-HCH, γ-HCH, HCB, PCB, DDT-family, pentachlorobenzene and octachlorostyrene.     

Die Organisation der Früherkennung von Umweltproblemen im Rahmen der wissenschaftlichen Beratung der Umweltpolitik

This study is based on the theses that

1. early diagnosis is indispensable in the context of precautionary policy for the management of environmental problems, which have the character of a “creeping disaster”; and that
2. the public must play the active role that is adequate within a democratic society. In the context of the study, three existing advisory committees for environmental policy as well as two concepts which have not been put into effect are investigated.

In the first part presented here, the concept of the Picht commission from 1972, which has never been realized in this form is introduced. In part II, the concepts and the working method of the three existing advisory committees (SRU, WBGU, TAB) are presented. Part III deals with the critique of these committees and an alternative concept of early diagnosis which has not yet been put into effect. In part IV, the work of the oldest of the committees, the SRU, is examined with respect to the three most important environmental problems of the last 15 years.     

Factors affecting adolescents’ use of urban public spaces in their leisure time: an exploratory study from the city of Vienna

Urban public spaces are important areas for leisure, recreation and physical activity and therefore contribute to the quality of life in cities. In particular, for adolescents they provide important spaces to meet with their peers, away from parental or school control. In many cities worldwide, public spaces have undergone severe developmental processes, and often a withdrawal from public space is noted. With regard to the opportunities those spaces provide for adolescents, it is necessary to investigate their current meaning for adolescents in a leisure context. In this article, qualitative research methods were used to investigate factors affecting adolescents’ use of public spaces in Vienna, Austria. In total 45 adolescents were interviewed. Results show that public open spaces are not regarded as important leisure spaces, and data reveal a strong retreat to private areas for leisure purposes. Perceived insecurities and fears support these processes and often result in avoidance of public spaces but also the wish for more control by authorities.     

Modelling visitor groups' intentions to displace from an urban trail: a combined stated preference and video monitoring approach

Depending on gender and activity, overcrowding and safety concerns may detract from urban green space use. Differences in use displacement intentions from a recreational trail in a forest in Vienna were investigated for male and female walkers as well as male and female dog-walkers (N = 425) using an image-based stated preference model. The trail scenarios were depicted as digitally calibrated images that systematically displayed combinations of levels of crowding with different mixes of user types and visitor behaviour. Visitors were asked whether the presented recreation scenario was so unacceptable that they would shift their use away from the presented trail. Hours and days of stated non-use of the recreation trail by various user groups are estimated by integrating the results of the behavioural model with annual visitation data. Use displacement intentions differed by gender and activity. High use levels were a greater concern for all respondents than very low use levels, particularly for female dog-walkers. However, only a small proportion of the recorded hours were heavily used. Safety concerns about very low use levels reduced the potential times of forest use for female walkers without a dog.     

Die organisation der Früherkennung von Umweltproblemen im Rahmen der wissenschaftlichen Beratung der Umweltpolitik

This study is based on the theses that

1. early diagnosis is indispensable in the context of precautionary policy for the management of environmental problems which have the character of a “creeping disaster”, and that
2. the public must play the active role that is adequate within a democratic society.

In the context of the study, three existing advisory committees for environmental policy as well as two concepts which have not been put into effect are investigated. The third part deals with the critique of these committees and an alternative concept of early diagnosis “General Ecological Monitoring” which has not yet been put into effect. In part I, the concept of the Picht commission from 1972, which has never been realized in this form has been introduced. In part II, the concepts and the working method of the three existing advisory committees (SRU, WBGU, TAB) have been presented. In part IV, the work of the oldest of the committees, the SRU, is examined with respect to the three most important environmental problems of the last 15 years.     

The Effect of Nitrogen Enrichment on the Carbon Sink in Coniferous Forests: Uncertainty and Sensitivity Analyses of Three Ecosystem Models

Estimates of the global carbon sink induced by nitrogen enrichment range vary widely, from nearly zero to 2.3 Gt C year^-1. It is necessary to reduce this uncertainty if we are to make accurate predictions of the future magnitude of the terrestrial carbon sink. Here, we present a Monte Carlo approach to uncertainty and sensitivity analysis of three ecosystem models, Century,BGCand Hybrid. These models were applied to a coniferous forest ecosystem in Sweden. The best estimate of the change in total carbon content of the ecosystem with the cumulative change in nitrogen deposition over 100 years, C_total/N_deposition was 20.1 kg C (kg N)^-1 using the pooled mean, with a pooled standard deviation of 13.8 kg C (kg N)^-1. Variability in parameters accounted for 92% of the total uncertainty in C_total/N_deposition, and only 8% was attributable to differences between models. The most sensitive parameters were those which controlled the allocation of assimilate between leaves, roots and stem. In particular, an increase in allocation to fine roots led to a large reduction in C_total/N_deposition in all models, because the fine roots have a very high turnover rate, and extra carbon allocated there is soon lost through mortality and decomposition.     

Thorium and uranium contents in human urine: influence of age and residential area

Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of (232)Th and (238)U in urine of unexposed Jordanian subjects living in six cities. The range of (232)Th excretion in all subjects was found to be 1.4-640 microBq d(-1) with an average of 34.8 microBq d(-1) (geometric mean 15.8 microBq d(-1)). Results showed no statistically significant correlation with age and residential area. The average value obtained is in agreement with levels considered normal in some recent publications. The average value of (238)U in all samples was found to be 3955 microBq d(-1) (geometric mean 1107 microBq d(-1)), which is higher than reported figures from Germany and India, but in agreement with those figures given in ICRP publication, number 23. The mean values of the different groups were found to be proportional to age up to 60 years. A noticeable drop is observed for subjects greater than 60 years old.