The use of potentially toxic substances (e.g., DDT, PCBs) has been either restricted or banned in several European countries during the last 30 years. As a result, there has been a marked reduction in their levels in rivers. However, other organic micropollutants suspected of having detrimental environmental effects, as well as many with so far unknown effects, are still being discharged into freshwater bodies.
Sediments are an essential, integral and dynamic part of European river basins. It is an important habitat as well as a major nutrient source for aquatic organisms. Sediments are also used for farmlanding and as a source of minerals and materials. Prompted by the WFD, views on sediments are changing and now recognize the key role they play in the preservation of river systems. Sediment management should fit into the holistic view of the role of sediments in river basin systems. This means that transboundary management is needed for river systems that cross national borders.
Sediments have an impact on ecological quality because of their inherent characteristics. Therefore, sediment monitoring programmes should be set up and address also their basic physical-chemical properties as well as the geomorphological processes within each river system, including those operating in oodplains, wetlands and coastal zones.