Contamination by hazardous substances is one of the main environmental problems in the eastern Gulf of Finland, Baltic Sea. A trilateral effort to sample and analyse heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), and organotins from bottom sediments in 2019–2020 were conducted along with harvesting historical data in Russian, Estonian and Finnish waters. We suggest that the input of organotins still occurs along the ship traffic routes. The tributyltin content exceeded the established quality criteria up to more than 300 times. High contamination by PAHs found near the ports, most likely originate from incomplete fuel incineration processes. The Neva River Estuary and Luga Bay might potentially suffer from severe cadmium contamination. The high ecological risk attributed to the HMs was detected at deep offshore areas. The simulated accumulation pattern qualitatively agrees with field observations of HMs in sediments, demonstrating the potential of numerical tools to tackle the hazardous substances problems.

Dioxins in the Gulf of Finland sediments, impact study during Nord Stream gas pipeline construction, data from 2010-2011

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.