PAHs, PCBs, heavy metals, TOC and grain size in the sediment of Belgian marine harbours.

The chemical status of five dredged spoil disposal sites in the Belgian Part of the North Sea, near the ports of Ostend and Nieuwpoort, is evaluated. A linear mixed-effect model was applied to PCB, PAH and heavy metal data from 2005-2014. No decrease in PCB concentrations was found, with even an increase at two disposal sites. Hg/AL ratios increased with 62% at one disposal site (BR&WS2) from 2005-2006 to 2013-2014. Cu and Zn concentrations increased at two disposal sites. Additional harbour sampling suggests that the latter is possibly linked to antifouling paints. Based on OSPAR environmental assessment criteria, the current chemical status of the sites suggests no chronic effect of dredged spoil disposal. However, increasing time trend data for PCB, Hg, Cu and Zn demonstrate the importance of monitoring to identify adverse trends.