Trace metals and Persistent Organic Pollutants concentrations in Narwhals from the Eclipse Sound

-PRELIMINARY REPORT-

Compiled by: ArctiConnexion

Presented by: The Mittimatalik Hunters and Trappers Organization

Presented to: the Impact Review Board- 2021 Public Hearings on BaffinLand Iron Mines’ Phase 2 proposal

January 2021 Introduction

Tasiujaq (Eclipse Sound) is the summer gathering, breeding and feeding ground for narwhals (Monodon monoceros) of the population (Pers. comm. Oomik, 2018; Watt et al., 2013, 2017). Since 2015, Eclipse Sound is used by the BaffinLand Iron Mines company as a shipping corridor for the transportation of six million tonnes of iron ore annually from a port located at the end of (Qinnguat) and towards international waters (Neary, 2020). The mine is located at approximately 80 km upstream the Milne Inlet port, in the Mary River area. Tailings of open-pit iron mine are known to carry trace metals like mercury, cadmium, lead, arsenic, chromium, nickel, zinc and copper either through the air, the water or soils (Ferreira and Leite, 2015; Li et al., 2021). Trace metals can contaminate terrestrial, aquatic, and marine ecosystems and, through biomagnification and bioaccumulation, can impact various species like caribou, fish and marine mammals, raising concerns on wildlife health and people as these animals are part of traditional diets (Braune et al., 2015; Dietz et al., 2013; Sonne et al., 2018).

Despite its important contribution to the diet of Inuit from Mittimatalik (), the narwhal of the Eclipse sound has received very sparse (and sporadic) attention especially in years following the implementation of mining activities including ore extractions, terrestrial transport, and maritime transport. Elders and hunters from the community have observed the contamination by red dust of the terrestrial environment and the sea-ice near Milne Inlet Port and are concerned by the potential impacts on narwhal health and on people (Pers. comm. Kunnuk, 2018).

This study tested the concentration of a series of trace metals in the tissues of narwhals harvested in the Eclipse Sound, as well as the concentration of Persistent Organic Pollutants (POPs). The report presents some preliminary results of the study.

Methods

Samples of muscle, liver, muktuk (skin), and blubber were sampled from 11 narwhals (3 males, 8 females) harvested by Inuit hunters in the Eclipse Sound and in the Milne Inlet during the month of June and August 2019, respectively. Samples were stored frozen at - 20°C. Traces metals were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) at the Environment Canada, Water Science and Technology Directorate Laboratory in Burlington, Ontario. Blubber samples from four adults and two juveniles were sent for Persistent Organic Pollutants (POPs) analysis to ALS Global (Burlington, Ontario). Organic Chlorinated Pesticides (OCPs) were analyzed following the EPA 1699 (modified) protocol, PolyChlorinated Biphenyls (PCBs) were analyzed by EPA-680, and Brominated Flame Retardants (PBDEs and PBBs) were analyzed by EPA-1614. Both laboratories are accredited through the Canadian Association for Laboratory Accreditation (CALA). Aging results were not yet available and the total length of the animal was used to discriminate juveniles to adult whales (Sonne et al., 2018).

Results

1. Mercury and Trace Metals The concentrations of total mercury (THg) measured in 11 narwhals are presented in Figure 1a. The highest THg concentrations were found in the liver ranging 3.0 to 39.0 mg kg-1 and averaging 16.8 ± 11.5 mg kg-1. THg concentrations were 10 to 20 times lower in the muscle (1.28 ± 0.63 mg kg-1) and the Maktaaq (1.05 ± 0.44 mg kg-1). We have not detected any significant effect of gender on THg, but THg was significantly lower in the liver of juveniles (ID#2 and #8) than adults. The concentration of THg in the liver and muscle of adult narwhals sampled in 2019 were apparently higher than concentrations in narwhals sampled in Pond Inlet in the late 1970s and most of the narwhals sampled in Greenland (Figure 1b). The average concentration of THg in liver of adults from Pond Inlet are 3 to 4 times higher in 2019 than in the late 1970s, while the average concentration of THg in muscle were 1.6 time higher in 2019 than in the late 1970s.

Fig. 1 – a) Concentration (mg/kg) of total mercury (THg) in muscle, liver and Maktaaq of 11 narwhals sampled in 2019 near Pond Inlet, Nunavut. Gender and life stages are indicated above the bars (F: female adult, M: male adult, and MJ: male juvenile (MJ). b) Comparison of Total mercury mean concentrations (mg/kg) in the muscle and liver of adult narwhals sampled in Pond Inlet in different years and throughout different Arctic locations. Error bars indicate the standard deviation except for NorthWest Greenland where it indicates the standard error. Data source : Pond Inlet 1977-1979 (Wagemann and Muir, 1984), Qikiqtarjuaq (Chan et al., 1995), SW Greenland (Dietz et al., 2004), NW Greenland (Dietz et al., 2004; Sonne et al., 2018), NE Greenland (Sonne et al., 2018).

The mean concentration of a series of trace metals measured in 9 adult narwhals are summarized in Table 1. As for THg, trace metals concentrations are generally higher in the liver than in muscle. Iron (Fe) concentrations were especially elevated (299 ± 49 mg kg-1 in muscle and 648 ± 291 mg kg-1 in liver) as well as the cadmium in liver (25.01± 39.90 mg kg-1) and the zinc (40.37 ± 13.27 mg kg-1 in liver and 24.67 ± 5.09 mg kg-1 in muscle).

Table 1 - Mean concentration (mg/kg) of trace metals in muscle, liver of adult narwhals (genders combined) sampled in 2019 near Pond Inlet, Nunavut. The trace metals presented here are typical of iron mine releases.

Comparing 2019 with the late 1970s, we found no difference between in the mean concentration of Cadmium and Zinc in the muscle and liver of narwhals near Pond Inlet (Figure 2a). In 2019 however, we noticed that the concentration of cadmium was very heterogenous among individuals (Figure 2b). The liver of individual #1 had a very high cadmium concentration (130 mg kg-1) relatively to others, suggesting that some narwhal can bioaccumulate high amount related to their habitat use and feeding choices. Comparison with other areas revealed no distinct trends in cadmium and zinc concentrations (Figure 2a).

Fig. 2 – a) Comparison of the mean concentration (mg/kg) of zinc (Zn) and cadmium (Cd) in the muscle (left panels) and liver (right panels) of adult narwhals sampled in Pond Inlet in different years and throughout different Arctic locations. b) Concentration (mg/kg) of cadmium in muscle (left panel) and liver (right panel) of 11 narwhals sampled in 2019 in Pond Inlet. Gender and life stages are indicated above the bars (F: female adult, M: male adult, and MJ: male juvenile (MJ). Data sources are for Qikiqtarjuaq (Chan et al., 1995), SW Greenland (Dietz et al., 2004), NW Greenland (Dietz et al., 2004; Sonne et al., 2018), Pond Inlet in 1977-1979 (Wagemann and Muir, 1984).

2. Persistent Organic Pollutants (POPs) The concentrations of Persistent Organic Pollutants (POPs) measured in 6 narwhals are presented in Figure 3. Overall, the concentrations of the four classes of POPs greatly vary among individuals with no apparent differences among gender. For example, individual #7 (male) and #13 (female) both exhibited high levels of POPs in all four classes. The concentration of total PCBs averaged 2340 ± 1849 ng g-1. Within OCPs, the DDT, the total chlordane-related compounds (CHLOR) and trans-Nonachlor show the highest concentrations and averaged 2466 ± 2321 ng g-1, 1835 ± 1401 ng g-1 and 1230 ± 994 ng g-1, respectively. The concentration of polybromodiphényléthers (PBDE) and Polybrominated biphenyls (PBB) averaged 17 ± 9 ng g-1and 0.32 ± 0.23 ng g-1, respectively.

Fig. 3 - Concentration (ng/g) of legacy (a) and new concern (b) Persistent Organic Pollutants (POPs) in the blubber of 6 narwhals sampled in 2019 near Pond Inlet. For the Legacy POPs are presented the Total PolyChlorinated Biphenyls (PCBs)(top-left panel) and some commons OrganoChlorine Pesticides (OCPs) (bottom-left panel). For the POPs of new concern, are presented the Total polybromodiphényléthers (PBDEs)(Top-right panel) and the Total Polybrominated biphenyls (PBB)(Bottom-right corner). Gender and life stages are indicated above the bars (F: female adult, M: male adult, and MJ: male juvenile (MJ).

Discussion

1. Mercury and Trace Metals The level of THg found in the liver of narwhals is the result of bioaccumulation over years and is typically higher in adults than juveniles (Loseto et al., 2008), as reported here (Figure 1). Total Hg, as a measure, does not allow for the discrimination of the toxic (Me-Hg) to the nontoxic (HgSe) forms of the mercury in the liver, which require further analyses. High mercury concentration in the liver can lead to hepatic lesions (Sonne et al., 2018) which can affect the metabolism and the neuroendocrine system of marine mammals (Lavery et al., 2009; Rawson et al., 1993; Sonne et al., 2007, 2018) as well as humans (Dietz et al., 2018; Merrill et al., 2001; Sonne et al., 2018). Toothed whales like narwhals are more inclined to bioaccumulate mercury as they cannot excrete this compound through shedding hairs like seals and polar bears can do (Dietz et al., 2013; Sonne et al., 2018). High cadmium concentration in narwhal liver and kidneys can also cause organ damages (Wagemann et al., 1996). Establishing the actual origin of the trace metals measured in the Pond Inlet narwhal tissues is challenging given the many potential sources including mining industry release, but also air and marine transports from southernmost latitudes and/or local release through the melting of permafrost (Braune et al., 2015). Interestingly, the relatively high THg, Cadmium, and Zinc concentrations observed in the Pond Inlet narwhals in 2019 (Table 1, Figure 2) are comparable to the NorthWest Greenland narwhals where the mining industry has been related to important punctual contamination (Søndergaard et al., 2014). For example, the Black Angel lead-zinc mine located in Maarmorilik (West Greenland) was in operation between the years 1973 to 1990 during which a total of 8 million tons of tailings was disposed in a nearby fjord (Søndergaard et al., 2019). Even two decades later, high concentrations of trace metals were found in seawater, sediment and numerous marine species such as mussels and fish (Larsen et al., 2001; Søndergaard et al., 2011, 2019; Sonne et al., 2014) which are prey species of the narwhal (Watt et al., 2017). Elders and hunters from the community of Pond Inlet have raised concerns about the red dust releases from the BaffinLand mining activities since its inception. This dust can carry trace metals and impact the marine ecosystem of Milne Inlet (Qinnguat), the main feeding and breeding ground of the narwhals. Elsewhere in South America, a life-cycle assessment of an iron mine has revealed the emission of chrome, zinc, and lead in the air, as well as the release of cadmium, arsenic, nickel, copper in the water with important ecotoxic impacts on the ecosystem and carcinogenic impacts on people (Ferreira and Leite, 2015). In addition, chemists have revealed that iron mines are particularly concerning when it comes to production, as trace metals can be transported over long distance through its adsorption onto sedimentary particles enriched in iron oxides and can be released far from the origin site (Cagnin et al., 2017; Michel et al., 1998; Pierce and Moore, 1982).

2. Persistent Organic Pollutants The legacy POPs were massively released in the environment by southern industries until their use became prohibited by decree of the Stockholm Convention (Braune et al., 2005). Their concentrations in wildlife have been shown to stabilize in several Arctic marine mammals (Braune et al., 2005). The mean PCBs concentration in the 2019 narwhals (2340 ± 1949 ng g-1) is lower than the concentration measured in 1982-83 (3937 ± 1865 ng g-1) near Pond Inlet (Muir et al., 1992). Concerning the OCPs, the concentration of DDT is twice lower in 2019 than in 1982-83, while the CHLOR concentration is similar between the two sampling periods. The trans-Nonachlor concentrations increased from 731 ± 383 ng g-1 in 1982-83 to 1230 ± 1994 ng g-1 in 2019.

The POPs of newer concern such as the PBDEs have been more recently added to the Stockholm Convention because of their exponential increase in recent decades (Ikonomou et al., 2002). This trend is of great concern for Arctic residents because it has also been observed to increase in ringed seals and beluga whales (Hoguet et al., 2013; Rotander et al., 2012). The concentration of PBDE in the 2019 narwhals (17 ± 9 ng g-1) is similar to concentration in beluga (15.5 ng g-1) from the western Canadian Arctic (Stern and Ikonomou, 2001).

Conclusion

The high contaminants load in narwhals of the Eclipse Sound, both trace metals and POPs, adds up to other industrial-based treats such as risks collision with vessels, noise pollution, and oil spill hazards. Closely linked to Inuit subsistence for centuries, the thriving of narwhals near Pond Inlet is vital for the community, and the monitoring of contaminants in this species and in the whole marine ecosystem of the Milne Inlet area should be regarded as a priority. Further addressing the linkages between trace metals release by the iron ore extractions and transport and its consequences on the marine fauna is critical.

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