Thirty years of monitoring Arctic coastal contaminants

For over 30 years, NIVA and Akvaplan-niva have collaborated on monitoring contaminants along the Norwegian Arctic coastline. In areas where trends could be detected, the levels and negative effects of most contaminants decreased over time. In cod, however, levels of some contaminants have risen.

The Norwegian Institute for Water Research (NIVA) and Akvaplan-niva annually monitor levels, time trends and effects of contaminants in cod, blue mussel, snails, and common eider, on behalf of the Norwegian Environment Agency. NILU Tromsø is also commissioned to perform some chemical analyses. The longest time series for cod and blue mussel in the Arctic run from the starting point in 1991.

The monitoring programme includes analyses of legacy contaminants, such as metals (e.g. mercury, lead, cadmium), tributyltin (TBT), organochlorines (e.g. PCBs, DDTs and HCB), tar substances (PAHs) and brominated flame retardants (PBDEs), as well as contaminants of more emerging concern, such as PFAS (“forever chemicals”) like PFOS, chlorinated paraffins and siloxanes.

Time trends and reference concentrations

Downward time trends for contaminants were prevalent in areas where trends could be detected. The programme has developed new reference concentrations for biota, and results from pristine areas, like Svalbard, are valuable in this regard.

Females with pseudopenis

When exposed to TBT, female snails can develop male sex characteristics, a phenomenon called imposex. TBT was used as an antifouling agent on boats until it was banned in 2008. We have detected no imposex at sampling sites in Svolvær and the Varangerfjord in recent years. These results from the Arctic, and the Norwegian coast in general, show that the TBT bans have been effective.

Some worrisome trends in cod

All cod analysed for PCBs, PBDEs and mercury in 2023 had concentrations that exceeded environmental quality standards. The only exception was cod sampled near Longyearbyen, which had acceptable mercury levels. The cod in the Arctic stations showed low overall load of contaminants, compared to more urbanised and/or industrialised locations further south along the Norwegian coast. Some metals showed increasing concentrations, for example silver in cod from the Varangerfjord and Tromsø harbour. Increasing concentrations of PBDEs were found in cod outside the Lofoten islands. Most surprisingly, PFOS concentrations were increasing in cod from Isfjorden in Svalbard.

Metals in Arctic blue mussel

In blue mussels north of the Arctic circle, the levels of contamination are generally low, but not substantially lower than in remote areas in southern Norway. The exceptions are nickel and cadmium, which were present at relatively high concentrations in mussels from the Varangerfjord. The metal smelter in Nikel, Russia (closed in 2020), has been the cause of high concentrations of nickel in the Pasvik river. Nickel in blue mussels has decreased at one station in the Varangerfjord, but not at the other one. Blue mussels from Svolvær have relatively high cadmium concentrations, which correspond with known high concentrations in crab from the area north of Bodø.

Common eider at Svalbard

Common eider females brood for 3-4 weeks, and during incubation they fast and lose much of their body weight. Stored lipid reserves are mobilised during fasting, and since many environmental pollutants are associated with lipids, this makes the eider an interesting species in which to study environmental contaminants. Blood and eggs of the common eider have been monitored since 2017 in Kongsfjorden, Svalbard. In the period 2017–2023 “no change” dominated for common eider, followed by downward trends. No upward trends were observed in 2023.

Stable isotopes as dietary markers

Stable isotopes of carbon and nitrogen are useful indicators of food origin and trophic levels. δ¹³C gives an indication of carbon source while δ¹⁵N increases in organisms with higher trophic level because of a greater retention of the heavier isotope (¹⁵N). Stable isotopes have been monitored since 2012 and have shown a geographical difference consistently over time. For instance, δ¹⁵N is highest in the Oslofjord, lowest on the West Coast, and intermediate along the coast of northern Norway. The isotopic signatures in mussels from the monitoring thus provide valuable information about the isotopic baselines along the Norwegian coast, including the Arctic coast.

Reporting

The data are reported to the Norwegian Environment Agency’s water environment database (https://vannmiljo.miljodirektoratet.no/), and the results are used by several organisations tasked with studying or protecting the natural environment, e.g. the Oslo–Paris Convention (OSPAR), the International Council for the Exploration of the Sea (ICES), the European Environment Agency (EEA), the Arctic Monitoring and Assessment Programme (AMAP) and the Norwegian Food Safety Authority.

 * Also affiliated with the University of Oslo