DOI: http://dx.doi.org/10.1065/jss2001.06.016
--- Management of contaminated sediments, i.e. linking risk assessment and problem solutions, needs both quality criteria respecting recent findings on bioavailability of pollutants and in-depth knowledge on processes controlling their particular hydrological and biogeochemical dynamics. - - -In the first part of our review, new insights into diagenetic mechanisms on particles including ageing and their effects on biological interactions were presented. These findings clearly indicate the need to refine bioavailability models including equilibrium partitioning. A set of bioassays is a powerful supplement to assess sediment quality. - - -In the second part, an interdisciplinary process approach relating to the release of DOC, nutrients and pollutants into the open water is described, which has been derived from the evaluation of the international state-of-the-technology with three major themes: experimental techniques, processes and properties and development and validation of models. Special study targets are the formation of aggregates in turbulent water, flocs and biofilms from organic reactions, and formation of new surfaces for readsorption of dissolved pollutants. Of greatest importance is the degradation of organic matter, which affects both hydrodynamic processes and geochemical redox cycles, thus providing driving forces, e.g. for metal mobilization.
Models for predicting pollutant transport in rivers are still dominated by hydromechanical parameters. A first step for extending these models could involve typical milieu factors such as competing ions, complexing agents, redox conditions and pH-values. The next steps would include binding constants and other factors describing solid/solution interactions of critical chemicals in a multicomponent system. - - - In the forthcoming issues of JSS-J Soils and Sediments, two practical fields of application will be discussed: in-situ sediment treatment – natural attenuation approach (Part III) and subaquous storage/capping of dredged material (Part IV). |
