Toxic Metals and Other Elements in Svalbard Reindeer

Description

Using ICP-MS and DMA-80, we obtained the concentrations of Hg, Cd, Pb, and other elements of interest in various tissues from Svalbard reindeer (Rangifer tarandus platyrhynchus), including kidney, liver, muscle, brain, blood, fur, and faeces. All tissue samples were freeze-dried and homogenized into a fine powder before analysis. For ICP-MS, samples were digested in nitric acid using a high-pressure microwave system. The following elements were quantified: Li, Na, Mg, Al, Si, P, S, Cl, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Sr, Y, Mo, Ag, Cd, Sn, Ce, Yb, Pb and U. In addition to tissue elemental composition data, we include information on soft biometrics (e.g., age, weight) and other relevant sampling details. All reported concentrations are provided in µg/g dry weight (dw). Blank cells indicate that the sample was not analysed for the compound, while N/A means that the concentration could not be detected above the LOD. Sex is noted as F=female and M=male. Calf represents whether the culled female had a calf by her side (Y) or not (N). Weight is provided as live weight. All weights are given in kg.

Steps to reproduce

Svalbard reindeer (Rangifer tarandus platyrhynchus) were culled in Nordenskiöld Land, Svalbard (77°50’–78°20’N, 15°00’–15°60’E) in October 2021 and 2022 under permits from the Governor of Svalbard. Post-mortem, whole blood was collected from the jugular vein in EDTA-lined vacutainer tubes. Fur samples (n=33) were collected from the dorsal area with scissors, and milk (n=7) samples were taken from lactating females. Kidney (n=36), liver (n=35), muscle (n=36), brain (n=15), faeces (n=36), and blood (n=17) samples were collected with stainless-steel instruments to minimize contamination. All samples were frozen at -20°C until processing. Prior to analysis, fur samples were washed in cycles with ultrapure water and acetone (VWR BDH®, >99.5%) to remove external contamination. The fur was left to dry in a fume hood while covered with disposable wipes until dry. Brain, kidney, liver, muscle, and faecal samples were freeze-dried for 72h at -50ºC and 0.04 mbar (average moisture content in the kidneys were 78.9%, liver 70.0%, muscle 69.9%, brain: 75.9%, and faeces 78.0%). The dried samples were homogenised using a plastic hammer until the entire sample was turned into a fine powder. Subsamples of blood and milk (approximately 1 mL) were homogenised using an ultrasonic processor for 2×10 seconds. All collected samples were analysed for total mercury (THg). In addition, kidney, liver, muscle fur and faecal samples collected in 2021 (n=18) were analysed for a range of additional trace elements. Hg analysis: approximately 40 mg sample was analysed for THg using thermal decomposition and atomic absorption spectrophotometry (Direct Mercury Analyser (DMA-80 evo) Milestone). The DMA-80 was calibrated using a Hg standard (in 2% HCl) with either a five- or seven-point calibration curve. A daily calibration check was performed following US EPA method 7473. The precision of the analysis was confirmed daily using certified reference materials, with recoveries ranging from 94 to 117% (M-3 HerTis, INCT-OBTL-5 and GBW 09101b Human hair). All sample Hg concentrations were corrected for instrument drift and blank values. Element analysis: approximately 400 mg of sample was added to PTFE vials with 5 mL of 50% (v/v) ultrapure HNO3. The samples were digested using a high-pressure microwave system (Milestone Ultraclave, EMLS) for 2.5h. The digested samples were diluted with ultrapure water to a final volume of 40 mL. Blanks (400 mg of ultrapure water and 5 mL of 50% (v/v) HNO3) and CRMs (1577b Bovine Liver and GBW 09101b Human hair) were also digested for quality control (recovery rates ranged from 84-108%). An 8800 Triple Quadrupole inductively coupled plasma mass spectrometry (ICP-MS) system (Agilent) equipped with a prepFAST M5 autosampler (ESI) was used to identify and quantify the elements. All elements samples were detected above the LODs in all samples, with the exception of Pb in a majority of the muscle samples.

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