Description: Das Projekt "Transport and fate of contaminants (WP EXPO 2)" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasserbau durchgeführt. Transport processes: The behaviour of contaminants in the water and sediments in river basins cannot be studied without taking into account the relevant processes in the basins and the boundaries with the upstream river system and the coastal region. The rivers that flow into these coastal areas take a considerable amount of contaminated sediments which are stored for longer or shorter periods in these estuaries. Retention of sediments will take place in the low-energy areas such as the smaller tributaries in the river basin. Within this work package various empirical formulations and characteristics will be defined that typically determine the sediment retention (e.g. hydraulic load and specific runoff). The estuarine regions of a river basin represent a diverse and complex water system. The tidal motion and the density currents induced by the change from fresh to saltwater are of particular importance in describing the water quality of estuaries. In the estuary strong intrusion of saltwater landward and current reversal might occur. The coastal area is characterised by the typical oscillations of the tidal movement and has a complicated current structure resulting from the horizontal intrusion of saline water and vertical stratification due to density differences. It is obvious that the estimation of the time and spatial behaviour of the exposure of contaminants in estuaries is complicated by the effects of tidal motion and chemical behaviour. In order to have an accurate description of the fate and distribution of contaminants in estuarine regions, a carefully analysis of model concepts and implementation is needed in this work package to assess the degree of complexity and valid merging of process formulations. Bio-chemical fate processes: Besides transport processes compounds are subject to many distribution and transformation processes or reactions which determine the exposure of contaminants within a river basin. Physico-chemical processes such as sorption, partitioning and evaporation determine the distribution between the water, air and particulate phases. Most compounds are subjected to transformation or degradation reactions, such as hydrolysis, photo-degradation, redox reactions and degradation by micro-organisms. The significance of degradation processes may vary with depth. For several compounds degradation is most prominent in the upper water layers, due to photo-degradation. Biodegradation rates in the lower water column are assumed to be lower. In anoxic sediments, biodegradation rates usually are much slower than in the water column. Many trace metals and persistent organic compounds are strongly bound to particulate phases or dissolved organic material or in the case of trace metals bound to inorganic and organic ligands. Usually only a limited fraction of a specific compound is present in a truly free dissolved state and available for uptake by aquatic organisms. usw.
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Stuttgart ? Ästuar ? Flussmündung ? Gerinne ? Anaerobe Bedingungen ? Schadstoffbelastung ? Europäische Gemeinschaften ? Anaerober Abbau ? Adsorption ? Bodendegradation ? Brackwasser ? Hydraulik ? Limnisches Ökosystem ? Photolyse ? Schadstoffimmission ? Spurenelement ? Verdunstung ? Salzgehalt ? Photochemische Reaktion ? Organischer Schadstoff ? Schadstoffausbreitung ? Schadstoffremobilisierung ? Sorption ? Wasserbau ? Wasserqualität ? Gewässerorganismen ? Wassergefährdende Stoffe ? Sediment ? Küstenregion ? Modellierung ? Hydrolyse ? Chemische Stoffeigenschaft ? Biologischer Abbau ? Chemische Reaktion ? Empirische Untersuchung ? Schadstoffverhalten ? Strömung ? Gezeiten ? Physikalische Größe ? Persistenz ? Flut ? Biochemische Reaktion ? Retention [Wasserwirtschaft] ? Schadstoffaufnahme ? Inkorporation ?
Region: Baden-Württemberg
Bounding boxes: 9° .. 9° x 48.5° .. 48.5°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2005-01-01 - 2006-06-30
Accessed 1 times.