Dredging and the dumping of dredge spoil
Dredging is carried out to maintain the depth of the navigation channels for shipping and to extract surface minerals. The government decides where, when and how much material may be dredged. It also decides where the dredged material can be dumped. The dumping of dredged material, or dredge spoil, at sea is covered by the Marine Pollution Act. Relatively clean dredge spoil is dumped at sea at sites near the ports of Rotterdam, Scheveningen and IJmuiden.
By the end of 2010 the Netherlands processed 250 million m³ of dredge spoil in total. This is dredged material removed from rivers, canals, ports, city canals, ditches, lakes and other water bodies in order to keep them free-flowing. Roughly one-fifth of the dredged-up beds is polluted with heavy metals, polycyclic aromatic hydrocarbon (PAHs) and mineral oil.