Summary
The results of this study do not provide a basis for concluding on an increase in the content of pollutants in “hovedsundet” or in the Botnavågen during the last 10 years. In a long-term perspective however, an improvement in the environmental pollutant content of the surface sediments (0-10 cm) could occur if new inputs of pollutants are stopped. For Gaddevågen, it appears that there has been an increase in the environmental toxicity content, especially for TBT and PAH compounds. The reasons for this are not known, but works on a new seawater pipeline at the bottom of Gaddevågen in 2018 may have contributed to spreading contaminated particles from this area. Before any further action is taken, the contamination situation should be confirmed by repeated monitoring and causes of increased concentrations in the surface sediment should be clarified. If there are ongoing activities or discharges that can affect the concentrations of contaminants in the surface sediment, it is important that these are stopped before any actions against contaminated seabed are implemented, in order to prevent recontamination.