Dredging activities can lead to the resuspension of contaminated sediments, resulting in a potential hazard for the whole ecosystem and also for human health. A six-months active biomonitoring was performed in order to monitor the trends of different classes of both legacy (organochlorine -OCPs -and organophosphate (OPs) compounds and polychlorinated biphenyls -PCBs) and emerging (polybromodiphenyl ethers -PBDE -and per-and polyfluoroalkyl substances -PFASs) organohalogen compounds, as well as polycyclic aromatic hydrocarbons (PAHs), in blue mussel (Mytilus edulis spp.) specimens transplanted at different depths in the Flekkefjord fjord. Such biomonitoring was performed to evaluate the efficacy of sediment restoration activities and to check for the potential environmental risk for the biota and food safety for human seafood. A negligible contamination by OCPs, OPs, PBDEs and PFASs was noted in mussels over the six-months biomonitoring, while a notable increase of the concentrations of PCBs and PAHs occurred in mussels transplanted at 15 m depth in three sampling sites within the fjord, as a consequence of an undersea landslide occurred during restoration activities. Levels of PCBs and PAHs suggested a potential risk for mussel predators and also for the human health, as they exceeded the limit set by European Commission for the consumption of bivalve mollusks. These results confirm the reliability of active biomonitoring to flank dredging activities aimed at ecosystem restoration in order to monitor the trend of contaminants and to estimate the potential risk for the aquatic communities and human health.

The present study aimed at measuring the levels of legacy and emerging contaminants in fillet samples from four demersal fish caught in two fishing sites from Southern Norway, in order to assess possible implications for food safety. Levels of organochlorine compounds (OCs), organophosphate pesticides (OPs), polychlorinated biphenyls (PCBs), polybromodiphenyl ethers (PBDE), per- and polyfluoroalkyl substances (PFASs), and polycyclic aromatic hydrocarbons (PAHs) were measured in fillet from Atlantic cod (Gadus morhua), European plaice (Pleuronectes platessa), lemon sole (Microstomus kitt), and European flounder (Platichthys flesus) specimens. A negligible contamination by all the investigated chemicals was noted in both the fishing sites, as very low levels of OCs, PCBs, and PFASs were noted in a limited number of individuals for each species. Considering the levels of contaminants measured in fillets of the four demersal fish species, negligible risk for human health for Norwegian consumers can be supposed.

The monitoring of contaminants represents a priority to preserve the integrity of marine ecosystems, as well as to plan and to manage restoration activities in order to protect environmental and human health. In the present study, a 6-months active biomonitoring was performed to explore the levels of eighteen trace and toxic elements, including heavy metals (TEs; i.e. Al, As, Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Sr, Ti, and Zn), accumulated in soft tissues of blue mussel (Mytilus edulis Linnaeus, 1758) individuals transplanted at different depths (5- and 15-m depth) in five locations within the Flekkefjord fjord (Southern Norway). As this area suffered a long-lasting contamination due to both organic and inorganic contaminants, a series of restoration activities were activated to tackle and to prevent potential risks for ecosystem and local population. Our results demonstrated that the levels of TEs accumulated in edible tissues of transplanted mussels in the Flekkefjord fjord were generally low before the beginning of the restoration activities. However, location- and time-specific differences in the accumulation of TEs were noted after the implementation of such activities. Interestingly, the levels of Fe and Mn significantly increased after the beginning of the restoration activities, likely because the release of these TEs from the slag used in such operations and/or resuspension of contaminated sediments. However, assuming that native mussels can accumulate the same TEs at levels measured in transplanted individuals, our results suggest a substantial safety for human consumption of native mussels from the Flekkefjord fjord, regardless of restoration activities.