PERSISTENT ORGANIC POLLUTANTS IN THE LIVERS OF MOOSE HARVESTED IN THE SOUTHERN NORTHWEST TERRITORIES, CANADA Nicholas C. Larter1, Derek Muir2, Xiaowa Wang2, Danny G. Allaire1, Allicia Kelly3, and Karl Cox3 1Department of Environment & Natural Resources, Government of the Northwest Territories, PO Box 240, Fort Simpson, Northwest Territories, Canada X0E 0N0; 2Aquatic Contaminants Research Division, Environment and Climate Change Canada, Burlington, Ontario, Canada L7S 1A1; 3Department of Environment & Natural Resources, Government of the Northwest Territories, PO Box 900, Fort Smith, Northwest Territories, Canada X0E 0P0. ABSTRACT: Moose (Alces alces) are an important traditional and spiritual resource for residents of the southern Northwest Territories and local residents are concerned about contaminants that may be present in the country foods they consume. As part of a larger program looking at contaminants in moose organs, we collected liver samples from moose harvested in two separate but adjoining regions within the Mackenzie River drainage area, the Dehcho and South Slave. We analyzed liver samples for a wide range of persistent organic pollutants (POPs) including polychlorinated biphenyls (PCBs), DDT related compounds, toxaphene, brominated diphenyl ethers (PBDEs) and perfluorinated alkyl sub- stances (PFASs). Overall concentrations of major groups of POPs (total (Σ) PCBs, ΣPBDEs, ΣPFASs were consistently low (generally < 2 ng/g wet weight) in all samples and comparable to the limited data available from moose in Scandinavia. PFASs were the most prominent group with geometric means (range) of 1.3 (0.81–2.5) ng/g ww in the Dehcho and 0.93 (0.63–1.2) ng/g ww in the South Slave region. Decabromodiphenyl ether (BDE-209) was the most prominent PBDE congener, similar to that found in other arctic/subarctic terrestrial herbivores. In general, BDE-209 and PFASs, which are particle-borne and relatively non-volatile, were the predominant organic contaminants. ALCES VOL. 53: 65–83 (2017) Key words: Dehcho region, POPs, polychlorinated biphenyls, perfluorooctane sulfonate, persistent organic pollutants, liver, moose, South Slave region, Northwest Territories INTRODUCTION Moose (Alces alces) are an important source of traditional food and of cultural sig- nificance for Canada’s northern First Nation communities, and is a frequently consumed food in the southwestern Northwest Territor- ies (NT) (Kuhnlein et al. 1995, Receveur et al. 1997, Berti et al. 1998). The long range trans- port and deposition of contaminants which often bio-magnify as they move through the food chain are of concern, especially as related to human exposure from consumed country foods (Van Oostdam et al. 2005, Donaldson et al. 2010). Recent studies have documented baseline levels of various heavy metals in the organs of moose from Northern Canada and Alaska (O’Hara et al. 2001, Gamberg et al. 2005a, Gamberg et al. 2005b, Arnold et al. 2006, Landers et al. 2008, Larter et al. 2016); however, informa- tion on levels of persistent organic pollutants (POPs) in the tissues of moose is scarce. Analyses conducted in the early 1970s indicated that moose in Idaho had very low Corresponding author: Nicholas C. Larter, Department of Environment & Natural Resources, Government of the Northwest Territories, PO Box 240, Fort Simpson NT X0E 0N0, Canada, nic_larter@gov.nt.ca 65 mailto:nic_larter@gov.nt.ca levels of organochlorine pesticides (OCPs) (Benson et al. 1973). Liver and muscle of moose from Denali National Park in central Alaska were analysed for a suite of POPs as part of the Western Airborne Contaminants Assessment Project (WACAP) (Landers et al. 2008). Low and variable con‐ centrations of PCBs and hexachlorobenzene (HCB), and OCPs were detected in 3 moose liver and muscle samples; DDT related com- pounds (p,p′- DDD + p,p′- DDT, ∼34–340 ng/g lipid weight (lw)) and HCB predomi- nated (∼0.1–0.72 ng/g lw). Moose muscle, fat, and liver from communities in the Mac- kenzie Valley of NT that had been cooked/ baked had total (Σ) PCB concentrations ran- ging from 3 to 23 ng/g (Berti et al. 1998), but raw muscle and liver were not analysed. Recent studies in Scandinavia report low con‐ centrations of a wide range of POPs in moose muscle and liver including PCBs, OCPs, poly- brominated diphenyl ethers (PBDEs), and polychlorinated dibenzo-p-dioxins/dibenzo- furans (PCDD/Fs) (Danielsson et al. 2008, Mariussen et al. 2008, Suutari et al. 2009, Holma-Suutari et al. 2016). A recent assess- ment of data for POPs in Canadian arctic food webs concluded that PBDEs, particular- ly decabromodiphenyl ether (BDE-209) and perfluorinated alkyl substances (PFASs), were the predominant halogenated contami- nants in caribou (Rangifer tarandus) with concentrations typically higher than PCBs or OCPs (Muir et al. 2013); no results for moose were included. As part of a study assessing baseline con- centrations of various contaminants in the organs of moose harvested for consumption by local residents, we analyzed livers to in- vestigate the baseline levels of a wide range of POPs and emerging contaminants of con- cern including PCBs, OCPs, PFASs, PBDEs, and non-PBDE brominated flame retardants (BFRs). Knowledge of baseline levels of these contaminants in moose is important be- cause comparable data are limited and moose consumption by local residents may increase in future due to the declining availability of caribou as an alternate country food resource. METHODS Supporting information regarding more specific description of analytical methods, quality assurance, and raw data is pro‐ vided in “Supporting Information” at http:// alcesjournal.org/index.php/alces. Reference to “Supporting Information” follows through‐ out, and nomenclature in tables beginning in “S” refers to tables in “Supporting Infor- mation.” Study Area The Dehcho (ca. 154,000 km2) and South Slave (214,000 km2) are administrative regions of the southern NT located substan- tially in the northern boreal forest where moose, boreal woodland caribou (R. t. caribou), and wood bison (Bison bison athabascae) are the dominant ungulates. The samples for this study were collected by local harvesters from Jean Marie River, Hay River, Fort Smith and Fort Resolution (Fig. 1). Moose samples First Nation harvesters were requested to provide biological samples and general infor- mation from harvested moose. For the pur- pose of this study, we requested a minimum 5 cm x 5 cm piece of liver, an incisor tooth, and the following information: name of hunter, date and location of harvest, sex, esti- mated age (calf, yearling, adult), general body condition (excellent, good, fair, poor), and whether pregnant (yes, no) (Table S1). Liver samples (n = 7) from moose harvested in 2006 in the Dehcho and in 2010 in the South Slave (n = 7) were analyzed for 202 individual organohalogen compounds. A first incisor from each moose was forwarded to Matson’s Laboratory (Manhattan, Montana, USA) for aging by counting cementum 66 POPS IN MOOSE LIVERS – LARTER ET AL. ALCES VOL. 53, 2017 http://alcesjournal.org/index.php/alces http://alcesjournal.org/index.php/alces annuli from the root of the first incisor; 1 June was used as the birthdate (Matson 1981). Liver tissue analysis Liver samples were analyzed for PCBs, organochlorine pesticides (OCPs), and other chlorinated organics (OCOs) following US EPA Method 1699 (US EPA 2007) by ALS Global Laboratories (Burlington, Ontario, Canada), except for 4 samples from the Dehcho which were analysed by Environ- ment Canada (National Laboratory for Envir- onmental Testing [NELT]); both labs are accredited by the Canadian Association for Laboratory Accreditation and ISO 17025 cer- tified. The NLET used previously established methods (Hoekstra et al. 2002, Muir et al. 2006), and 3 samples from the Dehcho were analyzed by both labs (see Quality Assurance section). For both methods, sample prepar- ation was done in a clean room laboratory (positively pressurized with carbon and high-efficiency particulate arresting filters) at the Canada Centre for Inland Waters (CCIW, Burlington, Ontario, Canada). Sample preparation, extraction, and cleanup/isolation of the OCPs, OCOs, and BFRs is described in detail in Supporting Information. Clean extracts were concentrated to a final volume of 40 to 100 L in isooctane prior to analysis by gas chromatography (GC) using either elec‐ tron capture detection (GC-ECD), GC high- resolution mass spectrometry (GC-HRMS), or GC-low resolution MS (GC-LRMS). A list of individual PCB/OCO/OCP analytes is pro- vided in Supporting Information (Table S2). The GC-ECD analysis was conducted on 7 Dehcho samples. Final extracts of all samples from South Slave and 3 of 7 from Dehcho were analyzed by GC-HRMS for 31 OCP related compounds (Table S2) using GC-HRMS at ≥10,000 resolution, and for 87 individual + co-eluting PCB congeners using GC-LRMS. Analyses of all PBDEs and other brominated flame retardants (BFRs) toxaphene-related compounds including Fig. 1. Locations of moose collected from the eastern Dehcho and South Slave regions of the Northwest Territories showing roads and communities. Moose were harvested in 2016 in Dehcho (▲) and in 2010 in South Slave (■). ALCES VOL. 53, 2017 LARTER ET AL. – POPS IN MOOSE LIVERS 67 22 polychlorinated bornane congeners as well as α- and β-endosulfan and endosulfan sulfate, were measured by GC- electron capture-negative ion mode (ECNI) low reso- lution mass spectrometry. PFASs were mea- sured in liver samples (0.25–0.30 g) as described by Lescord et al. (2015). Further details of analytical methods for all POPs are provided in Supporting Information. Quality assurance and data analysis GC-MS and GC-ECD analysis of the 3 Dehcho samples analysed by both methods indicated that GC-MS yielded 28–75% higher values for PCBs, HCB, and chlor- dane-related compounds (ΣCHL) and 49% lower values for ΣHCH (Table S3); the discrepancies may reflect the low sample concentrations. Recovery studies for OCPs, PCBs, and BFRs spiked into moose tissue prior to extraction were very good and pro- vided in Tables S4 and S5. Low levels of PCBs and PBDEs were present in lab blanks and therefore all results were blank sub- tracted. Method detection limits (MDLs) for PCBs, OCP/OCOs, and PBDE/BFRs were calculated for all analytes based on results from 6 laboratory blanks that were analyzed in the same laboratory at approximately the same time, where MDL = 3x standard devi- ation of the blanks. For analytes with non- detectable blank values, the instrument detection limit (IDL) based on a signal to noise ratio of approximately 10:1 was used for statistical calculations. Further details on quality assurance are provided in Supporting Information. Preliminary statistical analyses indicated that results for most individual analytes and total (Σ) groups were not normally distribu- ted based on the Shapiro-Wilk statistic <0.05 and coefficients of skewness and kurtosis > 2. Log transformed data generally were normally distributed. Correlations and comparison of means using the Student’s t-test were conducted with log transformed wet weight data using Systat Version 13 (Systat Software Inc., San Jose, California, USA). Results for males and females were pooled because preliminary analysis showed no significant differences in mean concentra- tions by sex. Also, mean concentrations of all major analytes were compared between adult moose (n = 8) and calves (≤ 1 yr; n = 6) and no significant differences were found; there- fore, only correlations with age were exam- ined. Significance were set at P ≤ 0.05 for all tests. RESULTS AND DISCUSSION Sample and Data Characteristics The 14 animals sampled were harvested over a wide area and based upon harvester reports, 13 of 14 were considered as excellent or good condition; one calf was rated as fair condition (Table S1). All moose from the Dehcho (n = 7) were harvested near the com- munity of Jean Marie River and likely came from one localized population. South Slave moose were harvested both east and west of the Slave River and were possibly from two localized populations (Fig. 1). Concentrations of major groups of POPs in moose liver are summarized in Table 1, and results for 202 individual analytes are provided in Tables S6, S7, and S8. A primary indication that low concentrations were com- mon overall is that only 95 of the 202 individ- ual target compounds were detectable (Table S6). Of these, 73 (Dehcho) and 67 (South Slave) were > MDL which is the 99% level of confidence that a given analyte is present (Gomez-Taylor et al. 2003). We report all results in order not to censor the data, but for those analytes