Die ökologische Bewertung von Seeufern in Deutschland

Goal and Scope

Details about the ecological function of lake shores as ecotones between land and lakes are not well-known. These ecotones are also heavily exploited and, in part, considerably changed. Whereas anthropogenic nutrient loading is decreasing, structural changes are increasing. Unfortunately, there is a deficit in methods of evaluation and decision processes.

Main Focus

Even the EU-water framework directive was no remedy for this deficit, as lake shores were included only implicitly. In this article several evaluation methods and their conceptual groundwork are presented. However, these methods were not developed for lake shore research. Therefore, criteria are proposed which could fulfill the specific demands of lake shore assessments. The management of lakes shores should consider structural and biological parameters, and be agreeable to local residents.

Results and Conclusions

In addition to conventional biodiversity methods, the ecology of lake shores could also be represented by a functional food net, for example in benthic invertebrates. But even quantification of biodiversity alone creates many problems. A simple biodiversity index cannot meet all the demands placed on a method of evaluation in complex situations, especially when coupled with additional information on structure, practicability, costs, etc. For these reasons, assessments for future management cannot be based on such an index.

Outlook

A possible approach to include this complexity in assessments is to apply mathematical models and theoretical order concepts.     

Analytik von Umwandlungsprodukten des Schwefellosts (S-LOST)

The results of investigations of the aquatic ecotoxicity of sternutators and their metabolites (phenyl arsenic compounds) are presented. The standardized luminescence inhibition test (LumisTox, Dr. Lange) with the marine bacteriaVibrio fischeri was applied according to the German norm DIN 38412, part 34. All investigated organic AS(III) compounds exhibit EC₅₀-values (50 % inhibition of the luminescence) of less than 1 mg/l, whereas all investigated organic As(V) compounds and inorganic arsenic show EC₅₀-values exceeding 100 mg/l     

Uran in Wässern

The study presents 172 measurements of the uranium²³⁸U and²³⁴U isotopes in ground water and 21 measurements of these substances in the rivers of Eastern Germany. The uranium concentration in the ground water ranged from under 0.1 mBq/l to over 1000 mBg/l with a mean of 12 mBq/l. The respective activity relationships of²³⁴U/²³⁸U ranged from 0.85 to 12.6 with a mean of 1.66. A comparison of these values with those in the literature demonstrates an agreement with more recent measurements obtained from water in Thuringia and Saxony which were seen to have a mean value of 19 mBq/l. The activity relationships of²³⁴U/²³⁸U which were seen to be substantially over the equilibrial value of 1.0 and which were found in a quite high proportion of the samples must be taken into consideration when evaluating these. The measurements of river water demonstrated values for the Elbe river which are related to the periods of extensive uranium mining in Saxony and Thuringia. Measurements performed in the catchment regions going into the Baltic Sea revealed substantially higher values than would be expected from the distribution of uranium in these areas. A number of reasons are discussed here in an attempt to explain these findings.     

Abschätzung der Belastung des Menschen durch bodenbürtige Stoffe

Different concepts for hazard assessment of 2,3,7,8-TCDD in soil are presented and a comparison of the approaches is made. Both approaches clearly show that hazard assessment should be site and use specific.