Current status and trend for POPs

Blood sampling in seabirds. Photo: Norwegian Polar Institute

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Atmospheric transport is believed to be the most important transport route for volatile and semi-volatile POPs (persistent organic pollutants) into the Arctic (AMAP 2004). Monitoring POPs in the air at Zeppelin observatory (close to Ny Ålesund, Svalbard) has revealed low concentrations with stabile or declining trends. One exception is HCB (hexachlorobenzene) that has increased significantly since 2003 (Nizzetto, 2014).

POPs in air

Increasing concentrations of HCB may be caused by evaporation of remobilized HCB from open-ocean surface waters along the western coast of Spitsbergen (Svalbard) which has been ice-free during the past decade (Hung et al., 2010; Ma et al., 2011). While pollutants such as HCB, HCH (hexachlorocyclohexane), PCB (polychlorinated biphenyl) and PBDE (polybrominated diphenyl ether) occur at higher levels at Zeppelin, compared to the levels found at Andøya in 2013, the highest concentrations of PFAS (polyfluorinated alkyl substances) and DDT (dichlorodiphenyl trichloroethane)  were found at Andøya in 2013 (Nizzetto, 2014).

Figure 4.4.9. Environmental pollutants such as HCB, HCH, PCB and PBDE occurred at higher levels at Zeppelin, compared to Andøya in 2013. The highest concentrations of PFAS and DDT were found at Andøya in 2013 (Nizzetto, 2014).Figure 4.4.9. Environmental pollutants such as HCB, HCH, PCB and PBDE occurred at higher levels at Zeppelin, compared to Andøya in 2013. The highest concentrations of PFAS and DDT were found at Andøya in 2013 (Nizzetto, 2014).

Concentrations of HCH during 2013 were in the same range at both observatories and followed the decreasing trends from previous years. Overall, HCHs are compounds which have shown the largest decrease since the beginning of the air monitoring at Zeppelin (a factor of 15). Annual mean concentrations of PCB are similar or slightly lower than in 2012 at Zeppelin and Andøya. Stable concentrations have been observed at Zeppelin during the last 3 years, but have decreased by a factor of 2-3 during the previous 5-10 years. Concentrations at Andøya follow a declining trend also in recent years, which results in larger differences compared to Zeppelin. PBDE levels were highest at Zeppelin and lowest at Andøya during 2013, and concentrations were higher than in 2012 at both stations (Figure 4.4.9). The concentration of sum PBDE at Zeppelin was the highest since 2007. No significant long-term trend of sum PBDE is measurable at any of the observatories. Concentrations of DDT at Andøya and Zeppelin were similar or slightly lower during 2013, compared to earlier years (Figure 4.4.9). This was also consistent for all congeners. The long-term monitoring at Zeppelin shows a significant reduction of the air concentrations of DDT. A strong seasonality was found at Zeppelin with 3-6 times higher concentrations in winter time (December-January) compared to warmer months (April-September). The levels of PFAS at Andøya were higher in 2013 compared to 2012 and 2011, while the concentrations at Zeppelin were the lowest since the monitoring was initiated in 2006. Monitoring results correspond to their anthropogenic applications and current use; and thereby with strong contributions of ongoing emission from primary sources. There is large variability in levels from year to year, and no strong evidence of decreasing trends. Monitoring shows no seasonal trends, and that concentrations of siloxanes at Zeppelin are 100 to 1,000 fold higher than levels of legacy POPs (Nizzetto, et al., 2014).

Riverine inputs of POPs to the Barents Sea


Concentrations of PCBs were found to be lower in river Pasvik, compared to rivers in the south-eastern parts of Norway (Kaste et al., 2012).

POPs in seafood

S. Boitsov (IMR)
For most monitored substances in the Barents Sea, levels of contamination in seafood are well below limit values for human consumption. There is one important exception for dioxins and dioxin-like polychlorinated biphenyls in cod liver. Comparison of POP measurements in Atlantic cod from 1991-93 in the Barents Sea to Atlantic cod from 2007 in Northern Norway showed no change in PCB levels, a slight decrease in DDT and HCB, and decreases in HCH and chlordans (Sange and Klungsoyr 1997, Bustnes at al. 2012). For dioxins and dl-PCBs the databases on levels in commercial fish has improved substantially since 2006. There is a decreasing trend of dioxins and dl-PCBs in the environment and therefore also in food. A decrease in exposure to dioxins and dl-PCBs from fish can be seen since 2006, as present exposure is estimated to be in the range of 40% of the exposure calculated in 2006. The decrease is likely due to a combination of more data on levels of dioxins and dl-PCBs in fish in 2014 than in 2006, and decreased levels of dioxins and dl-PCBs in the environment (VKM, 2014). Further, it is known that the levels of dioxins and dioxin-like (e.g. planar) PCBs are highest near the Norwegian coast and decreasing northward towards Svalbard.

In the western Barents Sea, IMR has conducted a monitoring program of organochlorine pesticides (OCs) such as HCHs, HCB, DDTs, and chlordanes in fish liver (various species). A relatively new group of emerging pollutants, brominated flame retardants of the type PBDE (polybrominated diphenyl ethers) has been monitored since 2009. Results over the last 12 years of cod and haddock monitoring are presented in Table 4.4.5.

Table 4.4.5. Range in average concentrations of selected POPs in fish liver per year, in µg/kg ww. (Data from IMR measurements 2000-2012).

# Species HCHs DDTs PCB7 PBDEs
1 Atlantic cod 1-10 70-200 80-190 6*
2 Haddock 2-10 10-60 30-120 3-5

Most compounds studied are found at background levels. For DDT in Atlantic cod (Gadus morhua) liver, the highest levels found fall into Class II of the classification system established for this group of contaminants by the Norwegian Environment Agency. This corresponds to “good condition” (the green line in Figure 4.4.10 below), i.e. concentrations above the background level but below any thresholds for possible effects. For PCB7, even highest levels in cod fall into Class I, “background” (the blue line in Figure 4.4.10). The classification system has only been established for cod liver.

Figure 4.4.10 also shows trends observed over time. Both for PCB7 and DDTs, both average and maximum concentrations seem to be decreasing since 2004, although PCB7 concentrations seem to have reached a minimum in 2009 and were slightly higher in 2012.

Figure 4.4.10 also shows trends observed over time. Both for PCB7 and DDTs, both average and maximum concentrations seem to be decreasing since 2004, although PCB7 concentrations seem to have reached a minimum in 2009 and were slightly higher in 2012.Figure 4.4.10 also shows trends observed over time. Both for PCB7 and DDTs, both average and maximum concentrations seem to be decreasing since 2004, although PCB7 concentrations seem to have reached a minimum in 2009 and were slightly higher in 2012.

POPs in sediments

Generally investigations of bottom sediments in the Barents Sea reveal low levels of POPs. Sum7 PCB — the sum of seven individual indicator PCB isomers (congeners) — ranged from 0.7 to 3.5 ng/g dry weight (d.w.), and HCB ranged from 0.3 to 2.0 ng/g d.w in samples from 2003 to 2005 (Zaborska et al. 2011). A gradient from southern to northern Barents Sea had increasing levels of Sum7 PCB and quite similar levels of HCB. Sediment cores had relatively uniform concentrations of both Sum7 PCB and HCB throughout the core, which indicates strong vertical mixing of sediments in the Barents Sea (Zaborska et al 2011).

Levels of PBDE brominated flame retardants, have been measured by IMR in surface sediments from South-Western Barents Sea and off Lofoten and Vesterålen Islands since 2009 as part of the national MAREANO (Marine AREA database for Norwegian coastal and sea areas) program of seabed mapping. Levels for the group of 28 congeners are quite low, close to or below detection limits for most compounds, and not exceeding 20 µg/kg dry weight for the sum of compounds at any locations. Results are illustrated in Figure 4.4.11.

Figure 4.4.11. The concentrations of PBDE (sum of 28 congeners) in surface sediments from South-Western Barents Sea (IMR data), in µg/kg dry weight.Figure 4.4.11. The concentrations of PBDE (sum of 28 congeners) in surface sediments from South-Western Barents Sea (IMR data), in µg/kg dry weight.

POPs in marine mammals and seabirds

POPs in organisms at the top of the food web are of major concern because of the accumulating properties of POPs. Levels of POPs in polar bears at Svalbard and Franz Josef Land are above the limits which effect hormone and immune systems. PCB has been found in especially high concentrations (Gabrielsen 2007, Letcher et al. 2010). The trend across the Barents Sea shows increased levels of PCB from western populations to eastern populations, probably due to greater long-range transport of PCB substances from Europe to Svalbard and the Barents Sea area. Levels of PCB have decreased from 1990 to 2002, with a levelling out at the end of this period (Henriksen et al. 2001). Recent studies have also found newer contaminants like BFH and PFC in polar bears in the Svalbard region (Smithwick et al. 2005; Muir et al. 2006).

In herring gulls, puffins, kittiwakes, and common guillemots from northern Norway and Svalbard declining concentrations of HCB, HCH, DDT and PCBs were observed in eggs from 1983 to 2003 (Helgason et al. 2008, Helgason et al. 2012). In glaucous gulls declining plasma levels of PCB and HCB were observed from 1997 to 2006 on Bjørnøya (Bustnes et al. 2011). In contrast, increasing levels of HCBD and were observed during the same time period, 1983 to 2003, in herring gulls, puffins, and kittiwakes (Helgason et al 2009). For PBDE, levels increased from 1983 to 1993 and decreased from 1993 to 2003, with a net increase from 1983 to 2003 for the same species (Helgason et al. 2009).

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