Contrasting trophic transfer patterns of cadmium and mercury in the Arctic marine food web of east Hudson Bay, Canada

We investigated trophic transfer of cadmium (Cd) through an Arctic marine food web in Hudson Bay and compared it with mercury (Hg), a metal known to strongly biomagnify. We evaluated blue mussel, sea urchin, common eider, sculpin, Arctic cod, and ringed seal for the influence of dietary and biological variables on variation in Cd and Hg concentrations. Age and size influenced metal concentrations among individuals within a vertebrate species. Consumer carbon and sulfur isotope values were correlated with their Cd and Hg concentrations, indicating habitat-specific feeding influenced metal bioaccumulation. Trophic transfer patterns for Cd depended on the vertebrate tissue, with food web biodilution observed for the muscle but not the liver. Liver Cd concentrations were higher in ringed seal and some common eider relative to prey. In contrast, we observed mercury biomagnification for both tissues. Tissue- and species-specific physiology can explain discrepancies of Cd trophic transfer in this Arctic marine food web.

Sociocultural determinants of alcohol and cannabis use and misuse among Nunavimmiut

OBJECTIVE

Stemming from historical traumas and changes in the Inuit way of life, substance use and its intertwined problems are a major cause of concern for Nunavimmiut. This study's objective is to investigate sociocultural determinants of substance use and misuse to inform culturally appropriate public health programs.

METHODS

The 2017 Qanuilirpitaa? survey was conducted among a sample intended to be representative of Nunavimmiut aged 16 and over (total n = 1326). Sociocultural factors included cultural identity, land-based activities, involvement in community activities, social support, and family and community cohesion. The frequency of binge drinking (5 or more drinks on one occasion), cannabis use, and problematic substance use (CAGE and DAST-10) were documented. Data were analyzed using weighted multivariate logistic regressions. Inuit partners were involved from the planning of analyses to the co-interpretation of results.

RESULTS

Nearly a third of Nunavimmiut aged 16 and over reported binge drinking at least once a week (29.3%), and 68.6% of drinkers were at risk of potential drinking problems. Forty-five percent (45%) reported using cannabis at least once a week, and 30% of drug users were at risk of potential drug abuse problems. Volunteering and participation in community activities were associated with lower odds of cannabis use, as was frequently going on the land with weekly binge drinking, potential drinking problems, and weekly cannabis use. Social support and community cohesion were associated with higher odds of weekly binge drinking, as was cultural identity (centrality scale) with potential drinking problems.

CONCLUSION

Key determinants of substance use relevant to Inuit culture were identified. Results are in line with our Inuit partners' experience in their communities and are coherent with current land-based interventions implemented in Nunavik. A thorough understanding of substance use contexts and related stressors should guide the content and implementation of substance use programs in Nunavik.

Smoking cessation attempts and successes among Nunavimmiut

OBJECTIVES

The smoking rate in Canada has declined in past decades, yet smoking rates remain high in Nunavik (northern Québec), where an estimated 80% of adult respondents smoke. We investigated sociodemographic factors, smoking behaviours, harm perception, and social support as determinants of smoking cessation attempts and successes among Nunavimmiut.

METHODS

Past year smoking frequency, quantity smoked, and cessation attempts and aids were documented in a sample of 1326 Nunavimmiut aged 16 and over in the Qanuilirpitaa? 2017 survey. Sociodemographic indicators, social support, cessation aids, and smoking harm perception were investigated as potential determinants. All factors were modeled by logistic regressions and adjusted for age and sex.

RESULTS

Thirty-nine percent of smokers tried to quit smoking in the preceding year, and 6% of those were successful. Older Nunavimmiut (aOR = 0.84 [0.78, 0.90]) and those smoking 20 + cigarettes/day (aOR = 0.94 [0.90, 0.98]) were less likely to attempt to quit. Ungava coast residents (aOR = 1.87 [1.36, 2.57]), separated/widowed/divorced individuals (aOR = 2.43 [1.09, 5.38]), and occasional smokers (aOR = 2.77 [1.61, 4.76]) compared to those living on the Hudson coast, single individuals, and daily smokers, respectively, were more likely to report cessation attempts. Most used no particular cessation aid (58%), 28% relied on family/self-help/support programs, and 26% used medication. Women were more likely to rely on spirituality/traditional methods (aOR = 1.92 [1.00, 3.71]) and less likely to rely on electronic cigarettes (aOR = 0.33 [0.13, 0.84]), as were older participants (aOR = 0.67 [0.49, 0.94]). Those with more years of schooling were more likely to rely on electronic cigarettes (aOR = 1.47 [1.06, 2.02]). These estimates are prone to biases due to the relatively low participation rate in the survey (37%).

CONCLUSION

Despite many attempts reported by participants, regional partners of this study underlined that successful smoking cessation remains a challenge for many Nunavimmiut. Key differences were identified in approaches and determinants of smoking cessation attempts, but most smokers did not use cessation aids. These results are in line with the experience of the Inuit partners of this study and can inform targeted public health interventions to support the many Nunavimmiut trying to quit smoking, notably increasing accessibility and acceptability of cessation aids. Inuit partners of this study highlighted the importance for interventions and communication efforts to reflect Nunavik's context.

Impacts of Proximity to Primary Source Areas on Concentrations of POPs at Global Sampling Stations Estimated from Land Cover Information

Given the considerable financial and logistical resources supporting long-term monitoring for air pollutants, and the use of these data for performance evaluation of mitigation measures, it is important to account for contributions from primary versus secondary sources. We demonstrate a simple approach for using open source Global land cover raster data from the National Mapping Organization from the Geospatial Information Authority of Japan to assess local source inputs for air measurements of legacy persistent organic pollutants (POPs)-polychlorinated biphenyls (PCBs) and organochlorine pesticides-reported under the Global atmospheric passive sampling (GAPS) Network at 119 locations for the time period 2005-2014. The land cover composition within a 10 km radius around the GAPS sites was identified to create source impact indicator (SII) vectors to quantify and rank the remoteness of the sites from human infrastructure. Using principal component analysis, three SII vectors were established to rank sites by impact of (i) general infrastructure/remoteness, (ii) urban infrastructure, and (iii) agricultural infrastructure. General infrastructure describes the combined effects of settlements and agricultural infrastructure. We found significant correlations (p < 0.05) between POP concentrations in air and specific SIIs. PCB levels in air had a statistically significant correlation to the SII ranking urban impacts around the sampling sites, while Endosulfan I, Endosulfan II, and Endosulfan sulfate had a statistically significant correlation with SII ranking agricultural impacts. The complete GAPS data set from 2004-2014 (1040 samples at 119 locations) was standardized based on the SII rankings to assess the global temporal trends of legacy POPs. SIIs were incorporated in the multiple regression analysis to determine global halving times. This includes short-term monitoring data from 79 locations that were previously excluded. Furthermore, the SII approach allows the integration of global monitoring data from different studies for broader global temporal trend analysis. This ability to link the results of independent and small-scale studies can enhance temporal trend analysis in support of the larger scale initiatives, such as inter alia, the Global Monitoring Plan and Effectiveness Evaluation of the Stockholm Convention in the case of POPs. This simple approach using open source data has a broad potential for application for other classes of air pollutants.

Changing environmental conditions have altered the feeding ecology of two keystone Arctic marine predators

Environmental change in the Arctic has impacted the composition and structure of marine food webs. Tracking feeding ecology changes of culturally-valued Arctic char (Salvelinus alpinus) and ringed seals (Pusa hispida) can provide an indication of the ecological significance of climate change in a vulnerable region. We characterized how changes in sea ice conditions, sea surface temperature (SST), and primary productivity affected the feeding ecology of these two keystone species over a 13- and 18-year period, respectively, in northern Labrador, Canada. Arctic char fed consistently on pelagic resources (δ13C) but shifted over time to feeding at a higher trophic level (δ15N) and on more marine/offshore resources (δ34S), which correlated with decreases in chlorophyll a concentration. A reduction in Arctic char condition factor and lipid content was associated with higher trophic position. Ringed seals also shifted to feeding at a higher trophic level, but on more pelagic resources, which was associated with lower SST and higher chlorophyll a concentrations. Years with abnormally high SSTs and reduced sea ice concentrations resulted in large isotopic niche sizes for both species, suggesting abrupt change can result in more variable feeding. Changes in abundance and distribution of species long valued by the Inuit of Labrador could diminish food security.