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Background Exposure to ambient particulate matter (PM) is known to be associated with increased morbidity and mortality in human populations. During the winter months in Fairbanks, Alaska, severe temperature inversions lead to elevated concentrations of ambient PM smaller than 2.5 microns (PM2.5). Sled dogs represent an easily accessible environmentally exposed population that may yield findings informative for human health risk assessment. Objectives In this pilot study, we evaluated whether ambient PM was associated with markers of global methylation in sled dogs. Methods Kennels were strategically recruited to provide a wide PM2.5 exposure gradient for the Fairbanks area. Continuous monitoring of ambient PM2.5 was conducted at each kennel during the winter of 2012/13 using a DustTrak 8530. Dogs received a physical examination and assessment of standard hematology and clinical chemistries. Global methylation was determined using the LUminometric Methylation Assay (LUMA) and 5-Methycytosine (5-mC) Quantification. Results Three sled dog kennels (n ~30 dogs/kennel) were evaluated and sampled. The average PM2.5 concentrations measured for kennels A, B, and C were 90 μg/m3, 48 μg/m3, 16 μg/m3 (p< 0.0001), respectively. The average (standard deviation) global methylation percentage for each kennel measured by LUMA was 76.22 (1.85), 76.52 (1.82), and 76.72 (2.26), respectively. The average (standard deviation) global methylation percentage for each kennel measured by 5-mC was 0.16 (0.04), 0.15 (0.04), and 0.15 (0.05), respectively. There was no statistically significant difference between the three kennels and their average global methylation percentage either by LUMA or 5-mC. Conclusions In this study we evaluated global methylation using LUMA and 5-mC and found no differences between kennels, though exposure to ambient PM2.5 was significantly different between kennels. As more information becomes available regarding immunologically-related canine genes and functionally active promoter subunits, the utility of this surrogate could increase.

The aim of the study was to evaluate the dynamic of cadmium, lead, copper, zinc, and iron among lower trophic levels, sea urchins and macroalgae. Diets and isotopic values were used in combination to explore trophic positions and potential transference of metals from primary producers to consumers. Concentrations of trace elements were measured in two species of sea urchin (Tripneustes depressus and Eucidaris thouarsii) and nine macroalgae that are usually used as food in four Sargassum beds, one of which is close to a phosphorite mine. Specimens were collected when Sargassum fronds were at their greatest (winter) and lowest (summer) abundance. Highest concentrations of Cd, and Cu in both urchin species were recorded in winter at the site near the phosphorite mine. Concentrations of Pb in T. depressus were below the detectable limit, whereas E. thouarsii, which in addition to a high concentration of Pb, had high amounts of Cu and Zn. Gut content analysis, indicates that the diet of both sea urchins at the four sites and two collection dates is mainly macroalgae. The δ15N isotopic values in sea urchins in a typical Sargassum bed were in good agreement with a diet dominated by macroalgae, with T. depressus having herbivorous habits and E. thouarsii having omnivorous habits in this environment. We found macroalgae important in the dynamics of metals in food webs, potentially contributing to transferring Cd, Cu, and Zn to key invertebrate species, such as sea urchins, indicating connectivity of food webs and ecological structuring of marine environments.

The use of sentinel species for population and ecosystem health assessments has been advocated as part of a One Health perspective. The Arctic is experiencing rapid change, including climate and environmental shifts, as well as increased resource development, which will alter exposure of biota to environmental agents of disease. Arctic canid species have wide geographic ranges and feeding ecologies and are often exposed to high concentrations of both terrestrial and marine-based contaminants. The domestic dog (Canis lupus familiaris) has been used in biomedical research for a number of years and has been advocated as a sentinel for human health due to its proximity to humans and, in some instances, similar diet. Exploiting the potential of molecular tools for describing the toxicogenomics of Arctic canids is critical for their development as biomedical models as well as environmental sentinels. Here, we present three approaches analyzing toxicogenomics of Arctic contaminants in both domestic and free-ranging canids (Arctic fox, Vulpes lagopus). We describe a number of confounding variables that must be addressed when conducting toxicogenomics studies in canid and other mammalian models. The ability for canids to act as models for Arctic molecular toxicology research is unique and significant for advancing our understanding and expanding the tool box for assessing the changing landscape of environmental agents of disease in the Arctic.

Fish skeletal muscle is often used to monitor mercury concentrations and is used by regulatory agencies to develop fish consumption advisories. However, the distribution of mercury species (MeHg+ and THg) in muscle tissue and other organs is not well understood in a number of fish species. Here we evaluate the spatial distribution of THg and MeHg+ in skeletal muscle and internal organs (heart, liver, and kidney) of 19 sculpin representing three species: Myoxocephalus scorpius (shorthorn sculpin n = 13), Myoxocephalus jaok (plain sculpin, n = 4), and Megalocottus platycephalus (belligerent sculpin, n = 2). Four subsamples of muscle were taken along the lateral aspect of each fish, from muscle A (cranial) to muscle D (caudal). Using Games–Howell post hoc procedure to compare mean concentrations of all tissues, muscle samples were significantly different from internal organs, although there was no difference between muscle-sampling locations. THg concentrations (ww) were higher in muscle (muscle A through D mean ± SD, 0.30 ± 0.19 mg/kg) than that in heart (0.06 ± 0.05 mg/kg), kidney (0.08 ± 0.06 mg/kg), and liver (0.09 ± 0.08 mg/kg). Percent MeHg+ decreased with age in both skeletal muscle and organs (p < 0.05). In contrast to some previous reports for other fish species, this study found significantly higher THg concentrations in muscle than in the liver. This study highlights the importance of using muscle samples when evaluating potential Hg exposure in risk assessments for piscivorous wildlife and human populations, and assumptions related to organ mercury concentrations should be examined with care.