Assessing and Managing Contaminated Sediments: Requirements on Data Quality – from Molecular to River Basin Scale*

Management of environmental risks in river basins needs to address quality aspects of sediment – both because of its storage capacity for contaminants and due to its potential function as a secondary source of pollution. Assessment of sediment quality, however, is still prone to a number of uncertainties and insufficient information with regard to regulation, analytical methods, risk assessment and risk management. The European Water Framework Directive (WFD), e.g., has not come up with environmental quality standards for sediments. Lack of harmonization, representativeness and traceability of sediment data, not fully understood processes governing bioavailability of sediment-bound contaminants, all add up to the uncertainty that needs to be quantified. This paper details uncertainties ranging from the molecular to the basin scale level with regard to sediment quality assessment and its integration into management approaches, and it suggests ways of how to cope with a lack of data and insecure data while still developing an overview of basin wide risks.