The initial risk assessment and emission control from contaminated sediments

Discharged persistent organic pollutants and heavy metals into the rivers are often assumed to adsorb on sediments without re-suspension, thus sediments may function as a sink for contaminants. Sediments, however, may also function as a (secondary) source of contaminants, depending on the hydrodynamic characteristics of a river. To assess whether the sediments function as a sink or a source of contaminants, a preliminary risk assessment using the so-called SEDINA tool (SEDiment INitial Assessment) is recommended. By comparison of the total concentrations of pollutants in sediments upstream, at, and downstream of the site area, the role of sediments can be determined. When the sediments functions as a sink, no specific sediments-related measures are required, although monitoring of the surface water and sediments quality is recommended. If the output of the SEDINA tool reflects that the sediments may function or function as a source of contaminants, the risk-reduction measures are necessary that may include emission control at the source(s), pathway(s) and/or receptor(s).